Displays

Aiming to explore and exchange ideas about the ecosystem services of organic wine production, this presentation will address two questions. First, what is the potential for improving ecosystem services? This is explored at the continental scale, looking at the spatial distribution of the effect of organic management practices in permanent crops. Second, how can the targets be reached based on public and private solution? This is explored based on local policy targets and contract based solutions including the private sector and the value chain. A case study of organic wine production in the Spanish Denomination of Origin Rueda is presented as a practical example. The content of the study is based on the results of the iSQAPER (http://www.isqaper-project.eu/) and CONSOLE (https://console-project.eu/) H2020 projects.

How to cite: Iglesias, A., Garrote, L., Sotes, V., and Bardaji, I.: Ecosystem services of organic wine production – Linking different views, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5694, https://doi.org/10.5194/egusphere-egu2020-5694, 2020.

Arbuscular mycorrhizal fungi (AM fungi) and soil organic matter (SOM) can be important factors in soil fertility, cycling of nutrients, and plant productivity. It is still unclear whether greater AM fungi abundance is advantageous for plant productivity under nutrient-poor tropical soils despite the relatively common lack of phosphorus (P) and the purported benefit of AM fungi in obtaining and exchanging P with plants for carbon. We explored whether AM fungi and/or SOM augmented plant productivity in different field soils to test the hypotheses that AM fungi were important contributors to plant productivity and that the contribution by AM fungi is higher on soils with lower organic matter and presumably lower nutrient availability compared to soils with higher organic matter. We conducted a factorial experiment in the greenhouse with potted soils of either high or low organic matter (SOM) collected from each of three different land uses, grazed by wildlife in a protected area (Serengeti National Park, Tanzania), grazed by livestock, and cropland. Half the soils were sterilized to remove soil microbes, including AM fungi. Two grass species, Zea mays and Themeda triandra, were grown for 12 weeks in 8 replicates of each soil type and sterilization treatment. About 52.4% and 62.6% of Z. mays roots grown in non-sterilized soils were colonized by AM fungi in low and high SOM, respectively, and 38.1% and 46.7% of T. triandra roots grown in non-sterilized soils were colonized by AM fungi in low and high SOM respectively. Overall, the production of both plant species was significantly higher on control soils than sterilized soils, indicating that AM fungi likely contributed to productivity, and on soils with higher SOM. However, the separate contribution to the productivity of SOM and soil microbes varied significantly among plant species and soils from different land uses. Zea mays productivity increased most strongly to higher SOM, and declined with sterilization in agricultural, but not livestock or wildlife grazed soils. In contrast, T. triandra production was largely insensitive to SOM or sterilization except on wildlife-grazed soils, where it increased most strongly in unsterilized soils. Soil microbe impacts on productivity, therefore, may be driven more by host plant species than by lower nutrient supply, as associated with lower SOM. Furthermore, the results suggest that efforts to enhance productivity in uncultivated lands should perhaps focus on altering plant species composition, while efforts to enhance productivity in agriculture soils might not depend on beneficial soil microbes or additional fertilizer but instead on effective crop rotations to reduce soil pathogens.

How to cite: Soka, G. and Ritchie, M.: Contributions of soil microbes and soil organic matter to plant productivity in tropical savanna soils under different land uses, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-644, https://doi.org/10.5194/egusphere-egu2020-644, 2020.

Vermicomposting is a natural process that utilizes earthworms and associated microbiome to transform organic wastes into vermicompost by-products that are rich in beneficial microorganisms and nutrients such as carbon, phosphorus, nitrogen, magnesium, and calcium. Liquid vermicompost extract (LVE), a derivative of the vermicomposting process, has recently gained interest among scientists and organic farmers due to their potential ability to enhance tripartite plant-microbe-soil interactions that would lead to improved plant and root growth, soil health and overall crop yield productivity. To investigate the short-term effect of LVE on soil mycorrhizal inoculum potential (MIP) and plant-mycobiome interactions, a field trial was carried out at CiRAA E. Avanzi, San Piero a Grado, Pisa, Italy.

The effect of LVE and its associated microbial and chemical components on soil MIP and AMF root colonization was evaluated on five summer crops, i.e. chickpea (Cicer arietinum L.), berseem clover (Trifolium alexandrinum L.), lentil (Lens culinaris L.), soybean (Glycine max L. Merrill), and sunflower (Helianthus annuus L.). The test plants were grown with or without the application of LVE in a split-plot trial with five replicates. Freshly made LVE from vermicomposting of wheat straws mixed with horse manure was screened for microbial properties using the Illumina Miseq sequencing platform. Seed inoculation with LVE was done before planting while field inoculation was done at the stem-elongation stage. Un-inoculated seeds and plots were used as controls. Soil MIP was assessed before planting and after harvesting, while AMF root colonization was evaluated at the mid-flowering stage of each crop.

The bacterial 16S and fungal ITS sequence analyses showed a high bacteria and fungal abundance and taxonomic alpha diversity present in the LVE. The most dominant taxa included Mucor, Citrobacter, Pseudomonas, Arcobacter, Azomonas and Clostridium. These microbes are commonly found in agricultural soil and are linked to the hydrolysis of complex organic matter, nutrient recycling, production of growth-promoting factors and siderophores, while others are known to produce peptide antimycotics and antibiotics that protect plants against pathogenic soil microorganisms.

The soil MIP significantly (p < 0.0001) differed between the two soil sampling times (before planting and after harvesting). It was evident that both seed and field inoculation with LVE significantly enhanced the soil MIP and this could benefit the next crop under rotation. AMF root colonization varied significantly across the crop species (p < 0.0001) and LVE treatment (p = 0.006). Highly nodulated lentils and berseem clover roots recorded significantly higher AMF root colonization than all the other crops. LVE inoculation had an overall positive effect on AMF root colonization with an average increase of 6.2% compared to the un-inoculated crops. These short-term results indicate that there could be a positive effect of the LVE inoculation on the soil MIP and AMF root colonization of our test crops, which could be attributed to the beneficial additive effects of the LVE that enhanced the tripartite plant-microbe-soil interactions.  

Keywords: Vermicomposting, Liquid vermicompost extract, Soil MIP, AMF root colonization, Legumes

How to cite: Koskey, G., Avio, L., Lazzaro, M., Pellegrini, F., Sbrana, C., Turrini, A., and Bàrberi, P.: Smart use of microbial-rich vermicomposting to enhance tripartite plant-microbe-soil interactions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3345, https://doi.org/10.5194/egusphere-egu2020-3345, 2020.

Cover crop mixtures of legumes and non-legumes have multiple advantages compared to bare soil like reducing erosion by covering the soil, fixing nitrogen from the air and reducing nitrate leaching, adding organic matter to the soil, increasing soil biological activity and improving soil structure. The advantages and disadvantages of a winter-hardy vs. a freeze-killed cover crop (CC) mixture were studied on an organic farm in Raipoltenbach in Lower Austria (10.5 °C, 760 mm) with non-inverting soil cultivation since 2008. Effects on soil inorganic nitrogen contents and the yield of a following maize crop were assessed. On an orthic Luvisol with a silty clay to silty loam texture, two field experiments (FE1 and FE2) were laid out in a randomized complete block design in four replicates in two consecutive years. The winter-hardy CC mixture was “Landsberger Gemenge” consisting of winter vetch, crimson clover and Italian ryegrass. The freeze-killed CC mixture consisted of fodder pea, common vetch, chickling vetch, buckwheat, phacelia and fodder radish. The winter-hardy catch crop mixture was terminated with a rotary cultivator and the freeze-killed CC was worked into the soil with a chisel on 4 April 2017 / 19 April 2018. After chiseling the soil (only in FE1), maize, cv “Connexxion RZ 340”, was sown on 4 May 2017 / 7 May 2018. In both treatments, soil was harrowed once in May and hoed twice in June. Soil inorganic nitrogen (N_in) was analysed in 0.0125 M CaCl₂ extracts. The winter-hardy CC had a biomass of 2.8 t ha^-1 on average when terminated in April, the freeze-killed CC reached on average 3.1 t ha^-1 in November. The N_in values in 0-90 cm soil depth in spring (2017 FE1 / 2018 FE2) were almost doubled in the freeze-killed CC treatment compared to the winter-hardy CC treatment. The winter-hardy CC mixture in took up soil nitrogen until termination in April, thus reducing N_in contents after winter and the risk of nitrate leaching during winter, saving nitrogen for the following main crop. An assessment in June (FE1) and May (FE2) showed no differences in the number of maize plants per m². Maize grain dry matter yield was 7.8 t ha^-1 in FE1 and 7.0 t ha^-1 in FE2 on average and did not differ between treatments. Also maize nitrogen yield did not differ. Sowing maize without inverting soil cultivation was more difficult in the winter-hardy CC treatment than in the treatment where the CC mixture was freeze-killed. But mainly due to the effective CC termination with the rotary cultivator, weed density was not higher in this treatment (except for one assessment date in July 2018 in FE2). In our study, both freeze-killed and winter-hardy CC mixtures consisted of a legume-dominated legume-non-legume mixture. This resulted in a narrow C-to-N ratio (10 to 13) in the CC biomass as a basis for a swift N mineralization from the CC residues in both treatments. Accordingly, maize grain DM yield and maize grain N yield did not differ between the CC treatments.

How to cite: Friedel, J. K., Fohrafellner, J., Wohlmuth, M.-L., and Gollner, G.: Soil inorganic N contents and maize yield following winter-hardy vs. freeze-killed cover crop mixtures on an organic farm in Eastern Austria, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13611, https://doi.org/10.5194/egusphere-egu2020-13611, 2020.

Conservative Agriculture (CA) practices are recognized to enhance soil organic carbon stock and in turn to mitigate the effect of climate change. One of the CA principles is to integrate cover crops (CC) into the cropping systems. The termination of CC before the cash crop sowing and the weeds control are the most critical aspects to manage in the CA. The technique currently adopted by farmers for the termination of CC implies the use of Glyphosate. However, the European Commission is currently discussing the possibility of banning the use of this herbicide due to the negative effects on human health and the agro-environment. The disk harrow (DH) or the roller-crimper (RC) can be adopted in CA as an alternative to the use of Glyphosate for the devitalization of CC, their incorporation into the soil (in the case of the disk harrow), and the reduction of weed pressure on the subsequent cash crop.

From November 2017 to October 2019, soil organic carbon (SOC, g kg^-1) and crop biomass production were observed in a 2-year field experiment located in Lodi (northern Italy), in which minimum tillage (MT) has been applied for the last 5 years. The soil was loamy and SOC was 16.2 g kg^-1 at the beginning of the experiment. The winter CC was barley (from November to May) and the cash crop was soybean (from June to October). The experiment consisted in three treatments replied for two consecutive years in a randomized block design: Glyphosate spray + DH + sowing + hoeing (MT-GLY); DH + sowing + hoeing (MT-ORG); RC + sod seeding (NT-ORG).

At the end of 2019, SOC resulted in a higher increase in MT-GLY (+15%) and in MT-ORG (+14%) than in NT-ORG (+6%; p<0.01). This was due to the fact that CC litter in NT-ORG was not in direct contact with soil particles and the process of immobilization was lower than in the other treatments.

Moreover, the increase in SOC resulted positively correlated to the CC biomass (2018+2019), which was significantly lower in NT-ORG. In particular, no differences of soybean and CC between the three treatments were observed at the end of 2018, but MT-GLY resulted in significantly higher CC and soybean biomass at the end of the second year (+32%, p<0.01). MT-GLY allows to stock more carbon via photosynthesis that in turn results in higher SOC content.

However, if we consider the tractor fuel consumption (for Glyphosate spray, DH, RC, hoeing), along with the biomass production, the carbon sequestration did not vary between the three treatments.

Further studies are needed for the definition of optimized field management practices to reduce the passage of machinery while increasing crop production and SOC.

How to cite: perego, A., acutis, M., and schillaci, C.: Alternatives to Glyphosate in conservation agriculture: effects on carbon sequestration in a field experiment in northern Italy , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13792, https://doi.org/10.5194/egusphere-egu2020-13792, 2020.

The compost from the wine industry as a source of nitrogen in vulnerable areas

Raquel Villena1, M. Teresa Castellanos1, M. Carmen Cartagena^1,2*, Ana M. Tarquis2 and. Augusto Arce^1,2.

¹ Departamento de Química y Tecnología de Alimentos. ETSIAAB-UPM. Avda. Puerta de Hierro 4. 28040 Madrid

² CEIGRAM-UPM. Senda del Rey 13. 28040 Madrid

*mariacarmen.cartagena@upm.es

Abstract

            The use of organic waste in agriculture, from the agri-food industry, is one of the most important outlets for this type of waste. Once that it is stabilized, it plays an important role in the context of circular economy. The application of this in vulnerable areas, where it is produced, is a possible substitute for traditional fertilization (fertirrigation) avoiding continuous contamination of aquifers.

            Spain is the third world producer of wine. This industry generates between two and three million tons of organic waste annually being more than half generated in Castilla - La Mancha. The residues of the wine industry, can be valued in many ways. One of them could be the agricultural application as a source of organic matter and nutrients, given its chemical characteristics. These residues aerobically treated can be used in horticultural crops in the same area, as a source of nitrogen substituting traditional inorganic fertilization.

            In this work, a three years’ field experiment was carried out in a drip-irrigated melon crop, traditionally grown in the area where also, these wastes are generated in Mediterranean climatic conditions in Castilla – La Mancha. The area is designated as “vulnerable zone” by the Nitrates Directive (91/676/CEE). The objective was to compare the behavior environmental and nutritional of organic fertilization versus fertirrigation. Due to the slow rate of mineralization of these residues in the soil, it is essential to know their residual effect on it. This effect was studied using wheat as a capture crop.

How to cite: Villena Gordo, R.: The compost from the wine industry as a source of nitrogen in vulnerable areas, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8961, https://doi.org/10.5194/egusphere-egu2020-8961, 2020.

The world’s agricultural and food systems vary by climate, geographic region, and local economic development conditions, but trade is making food products global in many cases, which is then followed by global interest in the efficiencies of production, water consumption, energy use, and emissions. Consumers want to know and consider in their decisions the environmental implications of the food they eat, and want to see profound reductions. Farmers and agricultural and food companies want to react positively and make changes, which is a challenge in the face of changing economic, climatic, labor, water, dietary, energy, labor, and emissions considerations and conditions.

Food, energy, and water systems are individually complex and inherently interdependent. Their joint study is both a necessity and a challenge. We have developed an integrated model of food, energy, and water systems to employ all three models simultaneously to tackle complex questions that span all three systems, but also problems that one would only see once the components and parameters of the three systems are in the same framework.

Our model accounts for the various inputs of agricultural production, food processing, and food distribution, from farm to consumer, including water, energy, biocides, labor, capital equipment, productivity, supply chains, transportation, retail and distribution, cooling, food processing, and food and packaging waste. The methodological basis for our model includes life-cycle assessment, life-cycle cost analysis, and a dynamic Bayesian network that allows us to propose optimal solutions in the face of changing conditions.

Through case studies we show what environmental and economic costs are expected to be when evolving water treatment technologies and sources (especially wastewater recycling, stormwater capture, and desalination) and water-saving technologies are deployed in most agricultural production areas of the world to maintain production in the face of climate change and disruptions. Packaging of products holds a key to reducing the environmental impacts of fruits and vegetables. Changing the electricity and energy supply has become an economically feasible opportunity. We incorporate into our model the enormous inefficiencies food waste represents.

The target audience for our model and results includes farmers and agricultural planners in the private and public sectors, individual consumers, water and wastewater agencies and companies, energy companies, food processors, and retail and distribution companies. Our model is globally applicable and scalable.

How to cite: Horvath, A. and Qin, Y.: An Integrated Food-Energy-Water Systems Model for Tackling Questions Related to Agricultural Produce and Food Supply Chains, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9890, https://doi.org/10.5194/egusphere-egu2020-9890, 2020.

Over the past decades, excessive use of fertilizers in cropland monocultures in combination with a decrease in fertilizer use efficiency, have led to an increase in nutrient leaching losses, especially for nitrate. Consequently, ground water pollution is widespread and starting to be recognized and potentially sanctioned by the European Union. Unfertilized tree rows alternating with crop rows (e.g. alley-cropping agroforestry) are hypothesized to act as a safety net by taking up excess nutrients below the crop-rooting zone. Here, we measured leaching losses of nitrogen (N), phosphorus (P) and potassium (K) during two growing seasons in agroforestry systems and adjacent monocultures at three sites in Germany, representing a wide range of soil characteristics. Leaching losses of N, P and K were generally lower under agroforestry tree rows at all sites compared to agroforestry crop rows or crop monocultures. Overall, agroforestry reduced nitrate leaching losses by up to 82% compared to monocultures, but showed comparable losses of P and K. Nutrient leaching losses were high in the agroforestry crop rows close to the tree rows where crop productivity is lowest due to resource competition with trees. An adjusted management, e.g. reduced fertilizer inputs close to the tree rows, may counteract these losses. Our results suggest that agroforestry has the potential to reduce nutrient leaching losses through the trees and the application of fertilizer should be reduced in the agroforestry crop row close to the trees. The reduction in nutrient leaching losses in agroforestry indicates an increase in the soil function of water filtration. In order to achieve large-scale implementation of temperate agroforestry, its environmental benefits need to be financially valued for farmers to adapt this widely applicable land use alternative. The presented project, SIGNAL (Sustainable intensification of agriculture through agroforestry) is part of the German research initiative BonaRes (Soil as a sustainable resource).

How to cite: Schmidt, M., Corre, M. D., Duan, X., Heinlein, F., and Veldkamp, E.: Does temperate agroforestry reduce nutrient leaching losses compared to cropland monocultures?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8528, https://doi.org/10.5194/egusphere-egu2020-8528, 2020.

Grassland management practices, such as grazing with varying animal density and mowing may impact the processes leading to soil organic carbon (SOC) accumulation. Although, they serve similar agricultural purposes, they differ in their effect on plant physiology and their influence on SOC remains uncertain. We hypothesised that both practices affect SOC storage differently due to an altered plant C input and changed growth and physiological response leading consequently to contrasting soil microbial activity.

Based on this, our experiment included the investigation of three grassland treatments: grazing at two intensities and mowing which are located at the experimental station of SOERE ACBB (Clermont-Ferrand, France). Additionally, we included bare soil and unmanaged abandoned site considering as negative and positive controls, accordingly. The aim of the study was to estimate how grazing and mowing affect SOC chemical characteristics and its link with microbial activity.

Our results show highest SOC contents under low grazing intensity, whereas SOC content under high grazing intensity was lower and did not differ from abandoned grassland. SOC content under mowing was lowest among all treatments but still higher compared to bare soil. Microbial biomass C (MBC) followed a similar pattern under high grazing intensity and positive control whereas it was similar under mowing and low grazing intensity and lowest under bare soil. Absolute enzyme activities showed a similar tendency as SOC content. However, enzyme activities per MBC resulted in highest values under low grazing intensity and similarly lower values under all other treatments.

These results demonstrate that microbial parameters responded to management in various ways most probably related to the differences in dung and litter inputs. We suggest that dung input under high grazing intensity increased MBC and consequently compensated for plant removal thus keeping SOC contents increasing. Consequently, grazing at both intensities allows to maintain SOC at similar levels as in absence of management. While on unmanaged land high SOC may be related to absence of harvest, on grazed land it may be related to stimulation of microbial activity due to animal activity. Mowing treatment on the other hand did not allow to increase SOC.

We conclude that the presence of animals in the system is essential to improve soil heath, biogeochemical cycling, and SOC storage.

How to cite: Gilmullina, A., Rumpel, C., Blagodatskaya, E., Dippold, M., Louault, F., Klumpp, K., and Chabbi, A.: Grazing and mowing impact on soil organic carbon and microbial activity in grassland soil, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9098, https://doi.org/10.5194/egusphere-egu2020-9098, 2020.

EPIC calibration and validation to predict crop yields and soil organic carbon dynamics among different management practices

Authors:

F. Briffaut^a, M. Longo^a. N. Dal Ferro^a, Furlan L^b, F. Morari^a

^aDAFNAE Dept., University of Padova, Viale Dell’Università 16, 35020, Legnaro (PD), Italy

^b Veneto Agricoltura, Settore Ricerca Agraria, Viale Dell'Università 14, 35020 Legnaro, PD, Italy;

Mathematical models are valuable tools to estimate agronomic and environmental effects of different management practices. Their use could be of interest for the evaluation of long term benefits associated with agri-environmental measures financed by European Common Agricultural Policy (CAP) through the regional Rural Development Programmes (RDP). In this study we focus on the simulation performances of the widely used agri-environmental model EPIC (Environmental Policy Integrated Climate Model). We tested the model ability in simulating crop yields, soil organic carbon (SOC) levels, soil volumetric water content (VWC) and water table depth in 44 plots from three farms located in the low-lying Veneto plain (North Eastern Italy). In each farm, three different management practices were used: conventional agriculture (CV), conservation agriculture (CA) and conventional agriculture with the use of cover crops (CC). The model was tested in the 2010-2017 period, with the first four years used as calibration period and the last as validation period.  We also compared the performance of two subroutines for simulating SOC: PHOENIX and CENTURY.

Differences among tillage practices were detected in the original data, with CA causing a reduction in yield, in particular for corn and soybean, but also a rise in SOC levels in the most superficial layers with respect to CC and CV managements.

First results showed that EPIC performance in reproducing crop yields and SOC content was satisfying (r² = 0.59 and NSE(Nash – Sutcliffe Efficiency) = 0.61, for crop yields and r² = 0.78 and NSE = 0.76 for SOC), while it was less accurate for VWC and water table dynamic (r² < 0.5 and NSE < 0.0). An improvement in the simulation of soil hydrology was obtained using a modified version of the model which incorporates the Richards equation. Another adaptation was the use of Johnsongrass (Sorghum halepense) to simulate weed infestation in CA managed plots which allowed to improve yields simulations.

This study demonstrated that EPIC can be a valid tool to predict patterns of environmental parameters under different management scenarios and therefore, once validated to local conditions, it could be used to support public administrations or farmers’ decisions.

How to cite: Briffaut, F.: EPIC calibration and validation to predict crop yields and soil organic carbon dynamics among different management practices., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17849, https://doi.org/10.5194/egusphere-egu2020-17849, 2020.

Assumed effects on land attributes have important implications for nearly all aspects of social, environmental and economic sustainability as well as policy designed to enhance sustainable agriculture. Life-cycle assessments, technical-economic assessments, and sustainability assessments of agriculture and bioproduct industries often use computational models to contribute to an understanding of complex processes. However, because the impacts attributed to a specific process or product must be interpreted in terms of a “business as usual” case, the reference scenario is a key factor in interpreting assessment results. Further, predictions of change are not equivalent to knowledge or data from empirical studies and instead can reflect underlying assumptions and embedded uncertainty from large input datasets. For example, in estimating soil organic carbon (SOC) dynamics, there is no internationally agreed SOC measurement protocol. This complicates the establishment of baseline scenarios for comparison across industries and continents (e.g. Brazil and the US: two of the largest bioproduct producers who often trade in equivalent products). If these models are used to accurately predict change and to justify the sustainability of a product, the reference scenario assumptions need to be realistic, measurable, and clearly documented. Justification for assumptions or simplifications should be based on published data and research that employs scientific principles and best available practices for measurement. We will present the results of a systematic literature review to determine the degree to which reference scenarios are explicitly defined when the effects of bioproducts are assessed; and to identify any published guidelines or rules for defining appropriate reference scenarios when assessing bioproducts. We will also present a summary of key aspects of a reference scenario and show the application of these principles to develop a SOC baseline for bioproduct assessments.

How to cite: Davis, M.: Reference Scenarios for Bioproduct Assessments: soil carbon and standardized reference scenarios, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12429, https://doi.org/10.5194/egusphere-egu2020-12429, 2020.

The modern Russian agroecological landscape evaluation is based on identification of areas with specific hydrology, soil and terrain constraints to crop, that are named as agroecological groups of lands. Soil quality of the lands is characterized by a combination of conditions ensuring sustainable crop yields and determining the ecological functions and stability of agrolandscapes. The main differences in soil quality in the forest-steppe of the East European Plain are due to soil erosion and precipitation redistribution by the topography elements. If the erosion processes are comprehensively studied by the world scientific community, then the influence of differences in soil moisture reserves, its spatial heterogeneity and potential impact on the crops productivity is not sufficiently considered by Russian specialists. In this regard, large-scale studies were carried out at two key areas: the Central Russian Upland (Kursk region) and the Oka-Don Lowland (Tambov region). The studies included conventional mapping with identification of agroecological groups of lands and their quality assessment using GIS and statistical analysis. To determine the spatial heterogeneity of the moisture conditions, the SIMWE simulation model was applied. This model calculates the precipitation redistribution by the topography elements using digital elevation model and several input parameters. It was find, that the territory of the Central Russian Upland is characterized by normal moisture conditions, leaching water regime, silty-loamy soil texture. Redistribution of precipitation occurs without delay, as a result of which most of the territory does not experience overmoistening and the soils are highly productive with moisture reserves in the top meter layer up to 150 mm. The spatial structure of soil water capacity in a meter soil layer was determined by the regression analysis method of the measured soil moisture and calculated runoff using the SIMWE model. It was determined that the intra-landscape variation of moisture capacity as an indicator of soil quality for agriculture is associated with the topography of the interfluves and the erosion. The second key area, the Oka-Don Lowland, is characterized by a lowland topography and clay soil texture, and excess of moisture in soils in almost all years. Several agroecological groups of lands with significantly different in soil water capacity. To determine the spatial structure of soil water capacity, the SIMWE model was also used, that showed a high intra-landscape soils diversity, that is due to a flat topography of interfluve with lots of depressions. The soils of drained interfluves with a short-term overmoistening and a groundwater level below 6 meters are of the highest quality. In addition, hydromorphic lands with groundwater above 6 meters and average annual moisture reserves in top meter soil layer up to 300 mm are distinguished. They occupy about 72% of the total area of ​​the key site. Such lands are suitable for cultivation of perennial grasses, winter wheat, soybeans, sunflowers and others.

This study is supported by Russian Foundation for Basic Research, grant №19-29-05277.

How to cite: Lozbenev, N. and Kozlov, D.: The agroecological soil quality assessment of Central-Russian upland and Oka-Don lowland of Russia. , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11317, https://doi.org/10.5194/egusphere-egu2020-11317, 2020.

Grasslands of the alpine and pre-alpine region do not only sustain economic soil functions such as fodder production for local dairy and cattle farming but also important ecological soil functions such as water and nutrient retention, erosion and flood protection and habitat provision for extraordinarily high plant and animal biodiversity. The current management in the more intensively used grasslands in this region is based on fertilization with liquid cattle slurry, which is assumed to be prone to high N leaching and gaseous N emissions with their undesired consequences for soil, air and water quality.

In order to assess the nitrogen use efficiency and trade-offs such as greenhouse gas emissions and nitrate leaching of liquid slurry surface application under the auspices of climate change, we set up a ¹⁵N cattle slurry labeling experiment, combined with a space for time climate change experiment using plant-soil mesocosms and lysimeters. The ¹⁵N signal was traced in the plant-soil-microbe system for an entire year to assess productivity, plant nitrogen use efficiency, soil nitrogen retention and nitrogen losses. We found surprisingly low plant nitrogen use efficiency (recovery of less than ¼ of the applied ¹⁵N in harvested plant biomass), soil N retention (ca ¼ ¹⁵N recovery) and high environmental N losses (ca ½ of the ¹⁵N tracer remained unrecovered). The estimates of N losses based on unrecovered ¹⁵N were in good agreement with independent measurements of gaseous and hydrological N losses. Due to very high productivity and associated N exports with grass harvests, total N exports exceeded total N inputs. Such soil nitrogen mining was especially pronounced in the climate change treatments and was supported by increased soil nitrogen mineralization.

We also tested alternative slurry management (slurry injection into the soil, slurry acidification) that is supposed to increase nitrogen use efficiency. Slurry acidification but not slurry injection slightly increased plant nitrogen use efficiency and reduced nitrogen losses, however could overall not prevent significant soil nitrogen mining.

Consequently, both surface application and the more modern techniques of liquid cattle slurry fertilization showed low nitrogen use efficiency and promoted soil nitrogen mining. This is asking for a re-consideration of traditional fertilization regimes based on solid manure mixed with straw, a management that over historical timescales likely contributed to the build up of the large nitrogen stocks in pre-alpine grassland soils.

How to cite: Zistl-Schlingmann, M., Kwatcho-Kengdo, S., Schreiber, M., Berauer, B., Jentsch, A., Kiese, R., and Dannenmann, M.: Nitrogen use efficiency of different slurry management in the pre-alpine grassland region – a 15N tracing experiment, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13759, https://doi.org/10.5194/egusphere-egu2020-13759, 2020.

Abstract

Grassland represents the dominant land use in Ireland, and the estimation of soil organic carbon (SOC) stocks and changes for Irish grasslands requires further improvements. This study uses the ECOSSE 6.2b process-based model in site-specific mode (Smith et al., 2010) to predict SOC stocks and changes associated with different grassland management practices. The work presented here aims to provide preliminary insights into SOC modelling procedures. Five Irish sites under different grassland management were selected from the 2009 LUCAS SOC database (JRC, 2018). Due to the lack of repeated SOC measurements over time, the initial SOC input values (required for the simulation initialisation) were assigned from the Irish NSDB database (EPA, 2007). This was done based on the site-specific information from both databases such as distance and matching land-use. The initial SOC values from the NSDB were assigned to 2002 (i.e. the start of simulation). Information on management was obtained from the Irish Integrated Administration and Control System database,LPIS (Zimmermann et al., 2016b), climate data were obtained from MÉRA (Met Éireann, 2018) and atmospheric N deposition from http://www.emep.int (Premrov et al. 2019). Fertilisation inputs were adapted from the literature and categorised based on stocking rates derived from Green et al. (2016). The 2009 yearly averaged SOC predicted values were compared to LUCAS measured SOC across five sites (r² = 0.06), showing over- and under-estimation of simulated SOC, which could be due to potential poor matching NSDB and LUCAS data. This result indicates that the repeated SOC field-measurements over the time are needed for proper model-parameterisation. This was further supported by the observed strong relationship between initial SOC inputs and ECOSSE predicted SOC (r² = 0.85) indicating the high sensitivity of model SOC predictions to the initial SOC inputs.

Acknowledgements

SOLUM project is funded under the Irish EPA Research programme 2014-2020. Thanks go to Dr Marta Dondini (U. Aberdeen) and Dr Rowan Fealy (Maynooth U.) for their support.

Literature

EPA, 2007. National Soils Database (NSDB). Environmental Protection Agency (EPA), Ireland.

Green, S., et.al., 2016. Cattle stocking rates estimated in temperate intensive grasslands with a spring growth model derived from MODIS NDVI time-series. Int. J. Appl. Earth Obs. & Geoinfo. 52, 166-174.

JRC, 2018. LUCAS 2009 TOPSOIL data, European Soil data Centre. Joint Research Centre. European Commission.

Met Éireann, 2018. MÉRA: Met Éireann Re-Analysis – Climate Re-analysis.

Premrov, A., et al., 2019. Biogeochemical modelling of soil organic carbon-insights into the processing procedures of selected atmospheric input data: Part II. IGRM2019.UCD. Dublin.

Smith, J., et al., 2010. ECOSSE. User Manual.

Zimmermann, J., et al., 2016. The Irish Land-Parcels Identification System (LPIS). Experiences in ongoing and recent environmental research and land cover mapping. Biol. & Environm. Proceedings RIA 116B, 53-62.

How to cite: Premrov, A., Zimmermann, J., Green, S., Fealy, R., and Saunders, M.: Insights into modelling of soil organic carbon from Irish grassland sites using ECOSSE model, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18940, https://doi.org/10.5194/egusphere-egu2020-18940, 2020.

Cultivation of Stropharia rugosoannulata on rice straw

Zhi Jin, Xue-Feng Hu

School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China

According to statistics, the annual output of crop straw in China attains more than 900 million tons. A C/N ratio of the straw of grass crops is too high to be bio-degraded rapidly when it returns to fields, adversely affecting the next rotation of crops. Therefore, the straw on the fields after harvesting is often treated with burning in China since the early history. The open-air burning, however, often causes the severe pollution of atmosphere, and has thus been forbidden by the Chinese government. However, the treatment of straw has become a headache problem since then. Stropharia rugosoannulata is one of the top ten mushrooms in the international mushroom market, as well as one of the important edible fungi recommended by the Food and Agriculture Organization of the United Nations to the developing countries. The rice straw, mainly composed of cellulose, hemicellulose, lignin, protein, resin and nutrient elements of Ca, P, K, Fe, Cu, Mn, Zn and Co, provides sufficient nutrients to Stropharia rugosoannulata. A field experiment was conducted to study the feasibility of growth of Stropharia rugosoannulata on fresh rice straw in the suburb of Shanghai after rice was harvested in late 2019. The cultured mycelia of Stropharia rugosoannulata were evenly sprinkled over fresh rice straw, and covered with a thin layer of soil and again with a layer of rice straw. The culture bed was kept at humidity of 70%-75% and temperature of 22°C-28°C. After two months, the sporophores of Stropharia rugosoannulata came out abundantly. This suggests that Stropharia rugosoannulata can grow and produce sporophores on fresh rice straw without addition of any organic manure. The sporophores of Stropharia rugosoannulata are treasures in food and highly enriched in human nutrients, with 25.75% of crude proteins, 2.19% of crude fat, 7.99% of crude fiber, 45.93% of carbohydrates and 16.72% of amino acids, as well as some antioxidants such as flavoniods, saponins and phenols. Moreover, the cellulose, hemicellulose and other non-biodegradable substance in rice straw were highly decomposed after the growth of Stropharia rugosoannulata, thus making it rapidly available to crops when returning to fields. With high content of organic matter and available nutrients, free of toxic heavy metals, the fungal-degraded rice straw is high-quality organic manure and will be chosen to be applied to the organic farming system in Shanghai in the future.

How to cite: jin, Z.: Cultivation of Stropharia rugosoannulata on rice straw, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-995, https://doi.org/10.5194/egusphere-egu2020-995, 2020.

A soil inhabiting fungus, Ophiosphaerella korrae (J. Walker & A.M. Sm. bis) Shoemaker & C.E. Babc. has been confirmed to be pathogenic to barley, durum wheat and bread wheat of the major crops (Hong et al., 2018; Tomioka et al., 2019ab). Foliage and spikes of the affected plants early blight with root rot and ripening disorder. In this study, we revealed virulence of the fungus to rice, which is also one of the major crops. When a rice cultivar (cv. Norin No. 22) was grown in pots in artificial climate chambers after being sowed with culture discs (6 mm in diameter) of the fungus (strains MAFF150117 and MAFF150118 from bread wheat and durum wheat, respectively) on synthetic nutrient agar (SNA) (1 disc per seed), growth delay and early foliage blight (including ripening disorder) with rotting of roots and stem bases occurred. Defect rates were 22% and 84% for the plants inoculated with strains MAFF150117 and MAFF150118, respectively. Control plants simultaneously treated with aseptic SNA discs had no symptom. The fungal strains were consistently isolated from all the inoculated plants, but not from healthy controls, demonstrating that the fungal strains were virulent to rice. Additionally, a decrease tendency of grain yield without symptom on foliage and roots was detected on a rice cultivar (cv. Koshihikari that is cv. Norin No. 1 × cv. Norin No. 22) inoculated with strain MAFF150117 in another pot experiment. Ophiosphaerella korrae is also known as a pathogen causing spring dead spot or necrotic ring spot of Bermudagrass (Wetzel et al., 1999ab; Camara et al., 2000; Iriarte et al., 2004; Gullino et al., 2007; Perry et al., 2010; Sasaki et al., 2010), Kentucky bluegrass (Wetzel et al., 1999a; Camara et al., 2000, 2001; Hayakawa et al., 2004; Wong et al., 2015), Louisiana grass (Wetzel et al., 1999a; Camara et al., 2000) and Zoysiagrass (Hayakawa et al., 2004; Tredway and Butler, 2007). We will investigate varietal difference against O. korrae as well as the fungal emergent ecology in the future.

[References] Camara et al. (2000) Mycologia 92:317-325 Camara et al. (2001) Mycol Res 105:41-56 Gullino et al. (2007) Pl Dis 91:1200 Hayakawa et al. (2004) J Jpn Soc Turf Sci 33 (Supplement 1):24-25 Hong et al. (2018) Pl Dis 103(1):158 Iriarte et al. (2004) Pl Dis 88:1341-1346 Perry et al. (2010) Mycopathologia 169:395-402 Sasaki et al. (2010) Jpn J Phytopathol 76(3):158 Tomioka et al. (2019a) Abstracts of papers presented at the 44th annual meeting of the pesticide science society of Japan, p 82 Tomioka et al. (2019b) Abstracts of papers presented at the 63th annual meeting of the mycological society of Japan, p 64 Tredway and Butler (2007) Pl Dis 91:1684 Wetzel et al. (1999a) Mycol Res 103:981-989 Wetzel et al. (1999b) Pl Dis 83:1160-1166 Wong et al. (2015) Pl Pathol 44:545-555

How to cite: Tomioka, K., Nagata, K., Chiba, M., Hidekazu, K., Ishikawa, N., Kawakami, A., Masunaka, A., and Sekiguchi, H.: Virulence of a soil inhabiting fungus, Ophiosphaerella korrae, to rice , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22630, https://doi.org/10.5194/egusphere-egu2020-22630, 2020.

Therapeutic horticulture is a discipline which belongs to both society and health sciences that has its own identity, which differentiates it from others. It arises as a result of the complementary fusion of two disciplines: horticulture and therapy or rehabilitation. In the therapeutic field, it incorporates some knowledges about physical, cognitive and sensory disabilities, different pathologies, psychosocial problems and special needs. Around horticulture, it allows us to develop knowledge about agriculture, gardening, landscaping, environment and others. It has been used, for educational and socialization purposes, for more than half a century, since then with great implantation and recognition in many countries.

The implementation of an organic garden with pedagogical purposes for students of Agroecology in the School of Agricultural Engineering of the University of Extremadura (Spain), has been the scene for the realization of a collaborative project of integrative - teaching - learning strategy between the University and the “Sorapán de Rieros” Foundation. This project has allowed the use of the ecological orchard created for pedagogical purposes based on the needs of students with mental disorders of different nature with whom the Foundation works, connecting then different points of view.

The specialized training in Permaculture, Organic Agriculture and Agroecology, the tutoring work with specific methodologies developed by the expert staff of the Foundation in Psychology and Psychiatry, as well as the coexistence with the University students has been an enriching experience, with enormously satisfactory results in the improvement of mental and physical health, as well as the labor integration of the Foundation students.

Keywords: Therapeutic horticulture, inclusive horticulture, mental health, organic farming, permaculture.

How to cite: Labrador, J., Pérez, A., Moreno, M. M., and Pérez-Vera, F.: Therapeutic and inclusive organic horticulture: an University-society collaborative learning experience, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8063, https://doi.org/10.5194/egusphere-egu2020-8063, 2020.

In recent years, the problem arising from the weed control in perennial crops is increasing, both in young woody crops during the first years of cultivation and in established plantations. The control of weeds through herbicides, the most widespread practice, presents many inconveniences, among which we can mention the appearance of weeds resistant or tolerant to them, crop phytotoxicities, especially in young plantations, or the significant reduction in the active materials allowed. Another aspect to take into account is the search for techniques that allow saving crop water consumption by reducing soil evaporation

Therefore, in this work we evaluate the effect of three mixtures based on by-products derived from the agricultural sector, mixed with a binder and recycled paper paste and applied in liquid form on the ground with subsequent solidification (hydromulch), on different soil parameters (soil water content, temperatura and flow of CO₂) in a young olive plantation in containers of 700 liters capacity. Additionally, two control treatments were included (manual weeding and a no-weeding treatments).

In summary, and as preliminary results, hydromulches increased the soil water content, reduced slightly the soil temperature in the summer season and increased the flow of CO₂, indicative of a higher soil microbial activity, closely related with the air temperature and the soil moisture. These preliminary results position hydromulches as an interesting alternative to herbicides and the conventional plastic mulches.

Keywords: hydromulches, soil CO₂ flow, soil temperatura, soil water content.

Acknowledgements: Project RTA2015-00047-C05-03 - INIA (Spanish Ministry of Economy and Competitiveness).

How to cite: Moreno, M. M., Villena, J., González-Mora, S., Atance, C., Ramírez, M., Campos, J. A., and Moreno, C.: The use of hydromulches in organic farming: Effect on different soil parameters in Central Spain, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17394, https://doi.org/10.5194/egusphere-egu2020-17394, 2020.

Organic biodegradation is a microbial controlled process that significantly influences soil fertility. The microorganisms involved are polymicrobial and organized in communities. Beyond this general statement, there are no reliable data available on the occurrence, structure and composition of polymicrobial biofilms in soil. The few published data are based on sequence analysis of unsystematically raised soil samples and provide no information to the involved biofilms, their structural organization or adherence to particles, which they are biodegrading.

The objective of the following proposal is tracking down polymicrobial communities and biofilms, which are responsible for biodegradation and which in turn, can be used as starter, indicator, and control tools for the targeted soil- and landscaping.

Over the last 30 years, the laboratory of polymicrobial infections and biofilms of the Charité hospital has developed multiple skills in identification, characterizing and monitoring of functional activity of polymicrobial biofilms in human body and gut specifically. One of the most striking results of these studies was the assessment, that bacteria within specific habitats of the mouth, tonsils, vagina or gut are not a faceless mixture of the once acquired participants, but structurally strictly ordered polymicrobial communities in which each participant takes its specific functional place.

Since the biofilms do not occur in all systems and at any time in relevant amounts, the mapping of biofilms is unavoidable and intentional. The assessment of polymicrobial communities on the FISH methods basis provides the biofilms mapping for the following objectives:

- identification of structured polymicrobial biofilms responsible for optimal composting, maximal soil fecundity, and reduction of environmental soil burden;

- modeling of soil fecundity based on polymicrobial starter and defined factors controlling their activity such as water supply, aerobe/anaerobe conditioning, pH, humic acids additives and other;

- testing of substrate bound polymicrobial biofilms as starter for the shaping of different lands and agricultures;

- development of soil-microbiological theoretical and technical fundamentals for the long-term soil improvement and efficient environmentally safe organic wastes recycling into the synthesized soil aggregate system under minimal sufficient intra-soil moistening and appropriate intra-soil mineral and organic matter, and waste load  (Biogeosystem Technique – BGT*).

The biochemical activity of the microorganisms till now is investigated solely in pure cultures. As soon as more than three different taxa are involved, the cultivation of microorganisms got problematic.

The main objective is the development of soil-microbiological theoretical and technical fundamentals for the long-term soil improvement and efficient environmentally safe organic wastes recycling in the synthesized soil aggregate system, for which microbial activity is decisive for polymicrobial infections and biofilms transformation into safe fertile substances.

Till now nothing is known about homology or interactions in arrangement and functioning of polymicrobial communities of colon and soil, and a new knowledge to fill this is needed.

Objectives of the study: to comparatively describe polymicrobial community dynamics in colon and soils; using BGT* methodology, to promote the function of polymicrobial biofilms in soil as a specific starter to insure the soil fertility, and to improve the human and soil health.

How to cite: Swidsinski, A., Kalinichenko, V., Zavalin, A., Glinushkin, A., Batukaev, A., Mukovoz, P., Minkina, T., Sushkova, S., Mandzieva, S., Chernenko, V., Gudkov, S., and Burachevskaya, M.: Bringing (Tracking) polymicrobial biofilms in Biogeosystem Technique methodology, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8489, https://doi.org/10.5194/egusphere-egu2020-8489, 2020.

Potential changes in soil quality as result of intensive agriculture are increasingly raising concerns about associated impacts and the need to implement more sustainable agricultural practices. Among several intensive crops, maize, an important human food source, is one of the most intensely produced around the world, representing harmful consequences for soil quality. Therefore, it is fundamental to understand how different agricultural management practices can influence soil quality. Hence, the main objective of this study was to compare the implications of the conventional tillage versus non-tillage in soil quality. Additionally, it was also an objective to evaluate how the implementation of herbage strips, non-irrigated and fallow areas, contribute to soil sustainability and biodiversity preservation, compensating the impacts of intensive maize cultivation. For this purpose, an integrative approach was adopted including physical-chemical parameters (e.g. bulk density, pH, electrical conductivity, field capacity, organic matter, nutrients) and biological parameters (e.g. phosphatase activity, urease activity, ecotoxicological tests with soil organisms).

The obtained results revealed the existence of differences between the analyzed practices, mainly associated with chemical parameters and nutrients. When comparing no-till and conventional sowing, higher mean values for no-till were observed for the following parameters: organic matter, cation exchange capacity, nitrogen, phosphorus, nitrates, calcium, copper, zinc, iron, manganese, urease activity and invertase activity. Hence, this study highlights the importance of the implementation of nonconventional agricultural practices, as is the case of no-till, as promoters of productivity and soil sustainability. Additionally, different management practices as herbage strip, non-irrigated and fallow areas around conventional areas play an additional role in soil quality and biodiversity preservation.

How to cite: Luísa, A., oliveira, C., Campos, I., Pelayo, O., Serpa, D., Kaizer, J., Gomes, A. P., and Abrantes, N.: Effect of different agricultural management practices on soil quality in maize intensive production., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19208, https://doi.org/10.5194/egusphere-egu2020-19208, 2020.

Predictions of N mineralization are still difficult but maybe this is due to the methodologies. Many soil tests have been proposed to predict N mineralization between field and laboratory experiment. Incubations of soil in the laboratory under controlled environmental conditions are most commonly used to assess N mineralization rates both from SOM and from added organic materials. However, predicting N mineralization due to the methods (the impact of using air-dried and fresh soil) has never been assessed before. If the results differ between the methods commonly used, there is a serious problem. Therefore, the objective of this study was to evaluate the influence of the incubation methods (air-dried vs fresh soil) to predict N mineralization. The N mineralization potential from fifteen agricultural soils in West and East Flanders – Belgium, were determined by aerobic incubation methods used air-dried and fresh soil at (20 – 25⁰C) for 84-days in the laboratory. The results indicated that total mineral nitrogen (NH4⁺ + NO3^-) concentrations and carbon content of microbial biomass (MBC) did not differ significantly between these methods. Nitrogen was mineralized in fresh soil incubations (0.36 mg N. kg^-1 soil day ^-1) while in air-dried soil (0.31 mg N kg^-1 soil day ^-1). Thus, the results generate that it may be conceivable to predict N mineralization by these two methods in controlled conditions.

How to cite: Banaty, O. A., Willekens, K., and De Neve, S.: How does measuring methodology impact N mineralization in controlled conditions and relations to soil biological parameters: air dried versus fresh soil, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22658, https://doi.org/10.5194/egusphere-egu2020-22658, 2020.

The impact of agricultural activities on soil fauna can be highly variable, depending on the management options adopted. High-input agricultural practices can promote a reduction in diversity of soil microarthropod communities but, at the same time can also favor bacterial-feeding fauna through the increase of bacterial foodweb pathways. In contrast, low-input practices can increase the dominance of fungal-feeding fauna through the promotion of fungal pathways. Responses also vary with time after fertilizer application and are strongly dependent on crop species or shifts in plant species composition due to fertilization.

The type of fertilizer, organic or inorganic, can also have diverse effects on soil organisms. Organic fertilizers can increase the population of soil decomposers serving as nutrient sources for other soil organisms. Inorganic fertilizers can indirectly affect the soil organisms by increasing crop growth, potentially leading to higher soil organic matter generation. However, inorganic fertilizers can also reduce species richness and abundance of microarthropods and earthworms due to acidification. Other soil fauna such as collembolan may not be particularly sensitive to nitrogen fertilization types. Nitrogen fertilization may disturb soil organisms in a manner that affects ecosystem functioning, but the links are not yet well quantified. Therefore, a compilation of available experimental field data on the effects of nitrogen fertilization on taxonomic and functional groups of soil fauna is needed to clarify the patterns and mechanisms of responses.

We are currently working on a quantitative review based on a global meta-analysis that will use paired observations from studies published across several countries. With this review, we aim to synthesize and discuss the current global knowledge on the effects of nitrogen organic and inorganic fertilization on soil fauna. Depending on data availability, we aim to quantify the responses of several groups of soil organisms to synthetic and organic nitrogen inputs, considering factors such as application rate or crop type. Our findings will be used for the development of modeling tools for the prediction of the impacts of agricultural management practices on soil functions.

How to cite: Betancur Corredor, B., Lang, B., and Russell, D.: Effects of nitrogen fertilization on soil fauna – A meta-analysis, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7779, https://doi.org/10.5194/egusphere-egu2020-7779, 2020.

Heterogenous flow pathways through the soil are a major component in the transport of water, dissolved and particle-bound nutrients like phosphorus (P) to water resources, and promote the eutrophication of water bodies. Non-uniform water flow patterns may also influence the spatial variability of the P-content in soils.

This study was designed to understand the spatial distribution of P in agriculturally used soils and the mechanism causing P accumulation and depletion at the centimeter scale. We conducted three replicate dye tracer experiments using Brilliant Blue on a loamy Stagnosol in North-Eastern-Germany. The plant-available phosphorus of stained and unstained areas was analyzed using double lactate extraction and diffusive gradients on thin films (DGT).

The DL-extractable P and the DGT-extractable P were strongly correlated (p<0.001, R²=0.63) confirming that DL-P is a good measure for the mobile phase of soil phosphorus.

The plant available P contents of the topsoil were significantly higher than those of the subsoil in all three replicates. The topsoil’s stained areas showed higher P contents than unstained areas, while the opposite was found for the subsoil. The P contents varied strongly over the soil profiles (0.4 to 11.2 mg P 100 g^-1) and different categories of flow patterns (matrix flow, flow fingers, preferential flow and no flow). The P contents of these flow patterns differed significantly from each other and followed the order: P_{matrix flow} > P_{finger flow} > P_{no flow} > P_{preferential flow}.

We conclude that P tends to accumulate along flow pathways in managed and tilled topsoils, while in subsoils at a general lower P level, P is depleted from the prominent preferential flow domains. It is likely, that P in the shallow groundwater origins from preferred flow zones from the subsoil.

How to cite: Koch, S., Lederer, H., Kahle, P., and Lennartz, B.: Flux fields affect the spatial distribution of phosphorus in a tilled loamy soil, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18732, https://doi.org/10.5194/egusphere-egu2020-18732, 2020.

It is widely recognised that the intensification of agriculture has had significant impacts on soil condition and function, negatively affecting soil structure, fertility and biological diversity. Such impacts have contributed to reduced soil carbon storage, hydrological function, the storage of nutrients, the filtration of pollutants and potential crop productivity. It is therefore important that agricultural systems adapt to ensure the provision of food alongside multiple other critical ecosystem services (ES). Developing our understanding of how to quantify soil function in a given state is important in calculating the value of soil ES and natural capital (NC) under different management scenarios. It is critical for both the establishment of cost effective agri-environment policies and in driving sustainable on-farm decision making at management appropriate scales. 

This study aims to examine how field methods, used for the assessment of soil condition and function, can be applied to determine (i) How baseline soil condition measurements relate to soil function across organic and conventional field sites and (ii) Whether enhanced soil function is observed in agricultural soils under organic agriculture and if so, whether the potential economic benefits could offset the loss in crop productivity.

The study was conducted at Clinton Devon Estate in South West England. Nine conventional and nine organic fields, reflecting the main rotational land uses on the estate, were selected. Baseline soil samples were collected from each field in winter 2018 for the analysis of; total carbon (TC), total nitrogen, plant available phosphorus, soil texture, pH and bulk density (BD). Land management data was collected from the farmers for each field. Four soil functions/services were selected for monitoring; nutrient filtering and retention, soil organic matter decomposition, carbon storage and crop production. Crop yields for maize, cereals and grass silage were collected from each of the soil sampled points immediately ahead of harvest in 2019. BD and TC from each sample were used to estimate carbon storage.  Three sites from each field were selected for the assessment of soil organic matter decomposition using the standardised and globally applied Tea Bag Index method (Keuskamp et al., 2013). A smaller sub-set of six fields (three organic and three conventional) were selected for the determination of nutrient filtering and retention. Porous pots, ten replicates per field site, were installed below crop rooting depths in October 2018 for monitoring through the 2018 – 2019 and 2019 – 2020 drainage seasons. A sample of soil pore water was extracted (fortnightly) and analysed for nitrate, nitrite, ammonia and phosphate, allowing a comparison of nutrient leaching between sites. 

The data from this study will be presented for the assessment of whether quantification of soil functions at the field scale can help in the identification of useful baseline indicators and contribute to the valuation of soil ES and NC. 

References:

Keuskamp, J.A., Dingemans, B.J.J., Lehtinen, T., Sarneel, J.M. and Hefting, M.M. (2013), Tea Bag Index: a novel approach to collect uniform decomposition data across ecosystems. Methods Ecol Evol, 4: 1070-1075. doi:10.1111/2041-210X.12097

How to cite: Holden, M., Brazier, R., Day, B., Bridgewater, S., and Watkins, Y.: Exploring field methods for the assessment of soil condition and soil function in order to estimate ecosystem service and natural capital value across organic and conventional field sites , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5797, https://doi.org/10.5194/egusphere-egu2020-5797, 2020.

Halting and reversing soil degradation as well as protection and sustainable use of soil as a resource are part of the United Nations Sustainable Development Goals. Despite the vital significance and essential functions of soil, massive amounts of fertile soil worldwide are lost due to improper land use. In Germany, approximately 66 ha of soil are damaged partly or completely in their soil functions daily. The main issues are soil erosion, land area claims for housing estate and transportation, and pollution. Until now, precise spatial location and assessment of the loss of valuable soil in terms of fertility and productivity has not been quantifiable and therefore not controllable.

In the SOIL-DE project, indicators to evaluate the functionality, potential, intensity of use, and vulnerability of soils are developed in order to be able to assess the quality and value of soils, both in retrospective and under current agricultural use. The aim of this survey is (i) to detect the loss of land over the past ten years in high spatial accuracy, (ii) to determine the fertility of the soil and (iii) to identify risk areas, i.e. regions with particularly high soil loss rates and high soil profitability. The threat to soil, the fertility and impairment of soil functions by changes in land use, are to be recorded nationwide and statewide. Therefore, the evaluation of time series from satellite images is used in combination with official soil information at different spatial resolution, as well as digital elevation models and climatic data. In this study, different rating systems are investigated including e.g. the Muencheberg Soil Quality Rating (ZALF), biotic potential yield, resistance to erosion, filter, buffer and transformation function, and runoff regulation. First results will be presented.

How to cite: Säurich, A. and Lilienthal, H.: Assessing the value and quality of German soils under agricultural use, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6654, https://doi.org/10.5194/egusphere-egu2020-6654, 2020.

Soils are at the heart of agro-ecosystems. In various parts of Europe, soils, their structure and function are under pressure from intensive farming practices and global changes. The main consequences are a loss of biodiversity, a decrease in organic matter content, an increase in their susceptibility to erosion. In this context, some farmers are adopting innovative practices to increase the quality of their soils. Among innovative practices, those related to conservation agriculture are particularly highlighted.

Conservation Agriculture practices are based on the threefold principles of (i) minimizing mechanical soil disturbance (e.g. no tillage), (ii) permanent soil cover, and (iii) diversification of crop species grown in the plots. These practices are encouraged by the farmers who adopt them and some stakeholders (ASBLs, advisors, etc.). Some related practices raise questions (use of herbicides) and the effects of the practices on the soil are subject to debate within the scientific communities.

The physical properties of soils are traditionally estimated by a series of laboratory tests that are resource-, time- and money-intensive. We propose to present a new pragmatic approach to assess the functioning and quality of agricultural soils, the 'slake test'. In the development phase, this approach has been tested for contrasting fertilisation and tillage modalities in various long-term trials at the Walloon Agricultural Research Centre (CRA-W).

A slake test is a simple and visual experiment shown by promoters of conservation agriculture. It consists of immersing a metal basket containing a soil sample and observing how this sample decomposes. It is done qualitatively, in two glass cylinders to compare soil samples from ploughed and no-till plots. Although this test is a quick way to assess the structural stability of a soil, its protocol has not been formalized and its results objectified by a quantitative method. We developed an original approach, the ©QuantiSlakeTest, aimed at continuously measuring the disintegration of the soil sample.

This original experimental design was first tested by comparing two contrasted treatments of a long term field experiment in Chastres (Belgium). This field experiment was conducted between 2004 and 2018 by the CRA-W for comparing soil management practices. Samples were taken from plots of treatment T (tillage) and treatment NT (no-tillage) in five repetitions (10 plots). In each plot, seven samples were taken in the superficial layer using Kopecky rings. The samples were dried 48 hours at 50°C before being tested. 

The application of ©QuantiSlakeTest highlights significant differences between tilled and non tilled plots. After one minute, the relative residual weight are significantly different between treatments (T: 0.76±0.16, NT: 0.95±0.06, p<0.001). At stabilisation, after 20 min, samples from tilled plots have lost more than 50% of their weight, while those from no-tilled plots have lost less than 30% (T: 0.49±0.32, NT: 0.71±0.22, p<0.001).

These early results confirm that ©QuantiSlakeTest is a credible approach for assessing the effect of soil management practices on soil stability, in controlled experimental conditions. We are now finetuning the protocol, trying the approach with room temperature dried samples and comparing other modalities (fertilisation, organic matter amendment).

How to cite: Vanwindekens, F., Hardy, B., Roisin, C., and Delporte, F.: A quantitative approach of the slake test for assessing soil structural stabilty, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9399, https://doi.org/10.5194/egusphere-egu2020-9399, 2020.

Soil compaction by field traffic is one of the main threats to all agricultural soils. Besides lower biomass productivity, compacted soils have a reduced regulation function which affects the air, water and nutrient cycles. To evaluate and mitigate soil degradation by field traffic, it is important to know where, when and to what extent soil compaction may occur during certain traffic events.

This study presents an approach to assess soil compaction risk at the field scale, considering the spatio-temporal changes of soil strengths and the machinery-induced changes in load and stress. Two newly developed models, the field traffic model “FiTraM” and the spatially explicit soil compaction risk assessment model “SaSCiA”, were used to evaluate the individual soil compaction risk for each field traffic activity during the maize cropping season. RTK-GPS data recorded by all farm vehicles served for the spatial calculation of traffic intensity and changing wheel loads at high spatial resolution (< 30 cm). These data were subsequently used for soil compaction risk assessment based on readily available soil and weather data.

Our model results indicated that nearly 95% of a field was trafficked throughout the maize-season; harvest traffic at high wheel load contributed to more than the half of the total trafficked area. Furthermore, the analyses showed that soil compaction risk varies greatly within individual fields. Soil moisture and soil texture variation inside the field results in varying soil strength and, therefore, in varying effects of field traffic on soil functions. Thus, one part of a field can be negatively affected by field traffic through an increase in dry bulk density and a decrease in hydraulic conductivity, while the other part is not affected.

In addition to the spatio-temporal assessment of field traffic intensity and soil compaction risk, the presented approach enables the calculation of maximum allowable wheel load until no harmful soil degradation occurs. Thus, the approach may support farmers in their decision-making for a more sustainable soil management.  

How to cite: Kuhwald, M., Augustin, K., and Duttmann, R.: Evaluation of agricultural field traffic by modelling traffic intensity and related soil compaction risk, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7366, https://doi.org/10.5194/egusphere-egu2020-7366, 2020.

While the change of soil functions under different management is important in the evaluation of long term strategies in agriculture, they are often difficult to be quantified. The obstacles are measurement problems on one hand, and on the other hand predictions for new management strategies and changing climate scenarios require estimates for yet unknown conditions. Comprehensive modeling of soil processes provides a road to both: Soil properties and processes that are per se difficult to measure can be included in a model to derive suitable indicators for soil unions. In this way, also, predicitons in the future for different climate scenarios and management strategies are possible.

In this presentation we give definitions for a limited set of indicators to quantify the most important soil functions in terms of both the current soil state and the soils’ potential to fulfill these functions. This includes the production of biomass, storage of carbon, storage and filtering of ground water, nutrient cycling, and habitat for biodiversity.

The quantitative evaluation of soil functions byel based indicators and their dynamics facilitates further socio-economic assessment and the development tools for governance.

How to cite: Weller, U., Lang, B., Mayer, S., Stößel, B., Vogel, H.-J., Wiesmeier, M., and Wollschläger, U.: Evaluating Soil functions based on modeling under the impact of land use, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18436, https://doi.org/10.5194/egusphere-egu2020-18436, 2020.

Soil organic matter decomposition affects the local and global C cycles. Decomposition is mainly affected by soil type and climatic conditions, for a given quality of organic material. This study tested the effect of land use and management, litter type, and climate on the early stage decomposition rate in long-term field experiments (LTEs) in Austria and Sweden. Standardized litter (Rooibos and Green tea) were used according to the Tea Bag Index (TBI) protocol (Keuskamp et al. 2013) for comparison of litter decomposition rate (k) and stabilization factor (S) in 11 sites in Austria (2015 and 2016) and 9 sites in Sweden (2016). The tea bags were buried at 8 cm depth and collected after ~90 days. Austrian LTEs focused on mineral nitrogen fertilization, mineral potassium fertilization, organic fertilization, tillage systems, and crop residues management. The LTEs evaluated in Sweden focused mainly on annual and perennial crops, mineral fertilization, and tillage systems. The impact of environmental parameters (air temperature and precipitation) was modeled to normalize the variance due to climatic effects at each site. The preliminary results show that in Austria TBI decomposition differed more between sites than between treatments at the same LTE. Minimum tillage treatment had significantly higher decomposition rates compared to reduced and conventional tillage. In Sweden, decomposition rate differed more between treatments than between sites. Fertilized plots showed higher stabilization than unfertilized, and maximum N fertilization had the highest k, while unfertilized had the lowest k. The effect of different tillage systems on k and S were variable across sites and treatments, although ploughing tended to result in the lowest k. The northernmost site resulted in the highest k value. Results indicated higher stabilization in perennial forage crops compared to annual crops. We also considered time-series decomposition for some sites with measurements at different time points by the TBI approach (retrieving tea bags after 15, 30, 60, and 90 days), and the use of Random Forest regressions to evaluate the importance of pedo-climatic variables on early stage decomposition.

How to cite: Gmach, M. R., Bolinder, M. A., Menichetti, L., Kätterer, T., and Sandén, T.: Effects of long-term field experiments on early stage litter decomposition in Austria and Sweden, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10280, https://doi.org/10.5194/egusphere-egu2020-10280, 2020.

Background and Objectives: Assessment of soil quality indices is important for identifying the effect of land use on soil function. Soil organic matter (SOM) is a major indicator of soil quality due to its capacity in affecting soil structure by enhancing aggregation. The aim of this study was to quantify the soil quality changes in pasture and agricultural lands around the Semirom city.

Materials and Methods: The study was conducted in a completely randomized design with five different levels including pastures, orchards, rain fed farming, irrigated cultivations of wheat and barley with 6 repetitions. A composite random soil sampling was done from the depth of 0-15 cm. Soil properties such as electrical conductivity (EC), pH, wet aggregate stability, particulate organic matter (POM), soil organic carbon (SOC) and carbohydrates were measured in each land use.

Results: The results showed that organic carbon (OC) and particulate organic carbon (POC) increased significantly in irrigated cultivation as compared to pasture. However particulate organic carbon was lower in rain fed farming compared with pasture. POC content were at least 2 times greater than those values in pasture and rain fed wheat farmlands. The highest carbohydrate amounts were observed in the irrigated wheat field (2 g kg^-1) while the lowest values were belonged to the rain fed wheat cultivations (0.94 g kg^-1). The content of carbohydrate had an increase of 40% in irrigated wheat field and a decrease of 50% in rain fed wheat field compared with pasture.The orchard and irrigated wheat and barley land uses had the highest mean weight diameter (MWD) of soil aggregates and the lowest values were obtained in the rain fed wheat and barley farming.

Conclusion: Overall, the survey results indicate a better soil quality of the orchards and irrigated farmlands, whereas the rain fed farmlands had more feeble soil quality as compared to other investigated land uses. Particulate organic carbon and carbohydrate showed greater sensitivity to land use changes. Therefore, these parameters are better indicators as compared to other investigated indicator for evaluating soil quality in the studied area.

How to cite: Chavoshi Borujeni, S., Chavoshi, E., and Nouri, H.: Changes in soil quality indices at different land uses in Semirom area, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21738, https://doi.org/10.5194/egusphere-egu2020-21738, 2020.

The study presents a geographically explicit model that uses multiple layers of environmental and social information to assess the environmental footprint of soil management practices at a 10 x 10 km resolution at the continental scale. Changes in soil environmental footprint are quantified in terms of the effect of management practices on soil productivity, nutrients and biodiversity. Changes in soil environmental footprint are quantified in terms of their effects on soil organic carbon, productivity and biodiversity. The central actor in the analytical process is the farmer, who is managing a plot of land where a certain crop is grown under a typical farming system. This plot of land is subject to policy scenarios, determined by the combination of agro-environmental determinants at the regional level, defined within the targets of the Common Agricultural Policy, environmental policy, market conditions and socio-economic development. Functional relations to define the effect of agricultural management practices on ecosystem services are formulated in qualitative terms. Results of different soil quality indicators are then combined to produce descriptions of improvement of soil environmental footprint. Soil Environmental footprint scenarios are then analysed in terms of improvements with respect to the current situation. Our results show that the Expected scenario is not enough to make significant contributions towards improving the soil environmental footprint and the Towards 2050 scenario delivers important benefits. The Regional Targets scenario delivers important benefits in key challenging areas, where the effects improve greatly the soil environmental footprint. The content of the study is based on the results of the iSQAPER (http://www.isqaper-project.eu/) H2020 project.

How to cite: Garrote, L., Santillan, D., and Iglesias, A.: Modelling the effect of agricultural policy scenarios on soil ecosystem services at the continental level, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8506, https://doi.org/10.5194/egusphere-egu2020-8506, 2020.

Soil organic carbon (SOC) is a key indicator of soil health, however, guideline values which indicate degradation and good status have been difficult to define. For soils in England and Wales, indicative management ranges were developed using ranges of SOC from the National Soil Inventory of England and Wales (NSI) for precipitation and clay content classes (Verheijen et al., 2005). Soils with higher clay content are often expected to have higher SOC content and this was evident in the management ranges. SOC interacts with clay particles through surface interactions and this, alongside occlusion in aggregates, is suggested to help protect SOC from decomposition and loss (Dungait et al., 2012). The management ranges, however, lacked a mechanistic perspective such that these might not be optimal ranges for soil physical properties and soil structure.

We have used the NSI to investigate how thresholds of clay/SOC might be used to assess SOC status. A clay/SOC ratio of 10 was proposed as a clay-SOC association capacity derived from correlations with soil physical properties (Dexter et al., 2008) and a further two thresholds (clay/SOC = 8 and 13) were proposed to indicate very good and degraded soil structural quality alongside the original threshold (Johannes et al., 2017). Comparing the distribution of soils under different land uses with the clay/SOC threshold ranges gave an increasing quality trend of arable << ley grassland < permanent grassland ≈ forest. The results suggested that 37% of arable soils would be considered degraded compared with 6% for grassland soils.

We have used the thresholds to define an index on a scale where negative values indicate degraded soils, and positive values (up to 1) suggest increasing quality beyond which a soil is considered very good. Data from the Woburn ley-arable rotation experiment (Johnston et al., 2017) have also been evaluated with this index to see how the index value might change with time under different managements. As a quantitative metric for SOC, this could form a monitoring framework and feed into other soil health schemes to assess a soil with respect to a clay-interaction capacity and expected soil quality.

References

Dexter et al. (2008). Complexed organic matter controls soil physical properties. Geoderma, 144(3–4), 620–627.

Dungait et al. (2012). Soil organic matter turnover is governed by accessibility not recalcitrance. Global Change Biology, 18, 1781–1796.

Johannes et al. (2017). Optimal organic carbon values for soil structure quality of arable soils. Does clay content matter? Geoderma, 302, 111.

Johnston et al. (2017). Changes in soil organic matter over 70 years in continuous arable and ley-arable rotations on a sandy loam soil in England. European Journal of Soil Science, 68, 305-316.

Verheijen et el. (2005). Organic carbon ranges in arable soils of England and Wales. Soil Use and Management, 21, 2–9.

How to cite: Prout, J., Shepherd, K., McGrath, S., Kirk, G., and Haefele, S.: A soil carbon index to gauge soil health in England and Wales, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19010, https://doi.org/10.5194/egusphere-egu2020-19010, 2020.

In the age of big data, constructing a database plays a vital role in various fields. Especially, in the agricultural and environmental fields, real-time databases are useful because the fields are easily affected by dynamic nature phenomena. To construct a real-time database in these fields, various sensors and an Internet of Things (IoT) system have been widely used. In this study, an IoT system was developed to construct soil properties database on a real-time basis and aim to a big data system analysis that can assess ecosystem services provided from soil resources. The IoT system consisted of three types of soil sensors, main devices, sensor connectors, and subsidiary devices. The IoT system can measure soil temperature, moisture, and electrical conductivity (EC) data on a five-minute interval. Also, the devices were applied to two test-beds near Chuncheon city in South Korea and have been testing for the stability and availability of the system. In a further study, we will add various soil sensors and functions into the developed IoT system to improve their availability. If the developed IoT system becomes to be stable and functional, it can contribute to constructing soil properties database on a real-time basis and a big data system that assesses soil ecosystem services.

How to cite: Lee, B., Lim, K. J., Yang, J. E., Yang, D. S., and Hong, J.: Development of an IoT system for sensing monitoring of soil properties, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12860, https://doi.org/10.5194/egusphere-egu2020-12860, 2020.

With the advent of remote sensing and its widescale implementation in the field of agriculture and soil studies, today remote sensing has become an integral non-evasive analysis and research tool. After decades of research with conventional optical remote sensing, both airborne and spaceborne, a need was felt to have an all-weather remote sensing data availability. Spaceborne SAR (Synthetic Aperture RADAR) or microwave remote sensing with its all-weather availability and high temporal resolution, owing to its penetration capabilities has been found highly suitable for the soil and crop health studies. Since, SAR remote sensing is highly sensitive to surface roughness and dielectrics in dry and moist soil conditions respectively, it becomes highly important to study and observe the variations of these properties in various polarisation channels. PolSAR (Polarimetric SAR) data with its different decomposition models has an advantage over conventional SAR data since it uses more than one polarisation channels and polarimetric decomposition models which consider several soil and crop parameters. This helps to study the RADAR wave interaction with the target easier. This helps in the proper and better study and understanding of retrieval of soil moisture and analysis of its variation over time. This study makes use of C-band Sentinel 1A satellite dual PolSAR, time series data of VV and VH polarisations. The datasets used are that of pre-monsoon and monsoon period of 2019, February to May respectively for Rupnagar area. In this study it has been aimed to model for retrieval of soil moisture based on RADAR backscatter values and Normalised Differential Moisture Indices values from Sentinel-1A and Sentinel 2 satellite imageries respectively. The process has been performed on both VV and VH polarisations and the results are analysed for both the time periods. Theoretically, it has been observed that VH polarisation yields better and nearer to ground truth results with least Root Mean Squared Error (RMSE) of 0.05 and high R²-Squared statistics of 0.72 (72%) in training and testing. This study aims at unsupervised modelling using satellite datasets for model development, training and validation and without the input of field data. The results though not very good yet give an idea of soil moisture estimation and is highly beneficial for areas and conditions when field validations and data collection is difficult or not possible. This study also aims at reducing field validation dependence. Once integrated with field data, accuracy is expected to increase.

How to cite: Tiwari, R. K. and Tripathi, A.: AN UNSUPERVISED SOIL MOISTURE ESTIMATION MODELLING APPROACH USING C-BAND DUAL PolSAR DATA, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12870, https://doi.org/10.5194/egusphere-egu2020-12870, 2020.

Soils and soil functions are recognized as a key resource for human well-being throughout time. In an agricultural and forestry perspective, soil functions contribute to food and timber production. Other soil functions are related to freshwater security and energy provisioning. In general, the capacity of a soil to function within specific boundaries is summarised as soil quality. Knowledge about the spatial distribution of soil quality is crucial for sustainable land use and the protection of soils and their functions. This spatial knowledge can be obtained with accurate and efficient machine-learning-based soil mapping approaches, which allow the estimation of the soil quality at distinct locations. However, the vertical distribution of soil properties is usually neglected when assessing soil quality at distinct locations. To overcome such limitations, the depth function of soil properties needs to be incorporated in the modelling. This is not only important to get a better estimation of the overall soil quality throughout the rooting zone, but also to identify factors that limit plant growth, such as strong acidity or alkalinity, and the water holding capacity. Thus, the objective of this study was to model and map the soil quality indicators pH, soil organic carbon, sand, silt and clay content as a volumetric entity. The study area is located in southern Spain in the Province of Seville at the Guadalquivir river. It covers 1,000 km² of farmland, citrus and olive plantations, pastures and wood pasture (Dehesa) in the Sierra Morena mountain range, at the Guadalquivir flood plain and tertiary terraces. Soil samples were taken at 130 soil profiles in five depths (or less at shallow soils). The profiles were randomly stratified depending on slope position and land cover. We used a subset of 99 samples from representative soil profiles to assess the overall 513 samples with FT-IR spectroscopy and machine learning methods to model equal-area spline, polynomial and exponential depth functions for each soil quality indicator at each of the 130 profiles. These depth functions were modelled and predicted spatially with a comprehensive set of environmental covariates from remote sensing data, multi-scale terrain analysis and geological maps. By solving the spatially predicted depth functions with a vertical resolution of 5 cm, we obtained a volumetric, i.e. three-dimensional, map of pH, soil organic carbon content and soil texture. Preliminary results are promising for volumetric soil mapping and the estimation of soil quality and limiting factors in three-dimensional space.

How to cite: Rentschler, T., Bartelheim, M., Díaz-Zorita Bonilla, M., Gries, P., Scholten, T., and Schmidt, K.: Volumetric soil quality modelling with machine learning in a diverse agricultural landscape in Andalusia, Spain, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-791, https://doi.org/10.5194/egusphere-egu2020-791, 2020.