SSS9.4

Organic farming and Soil management, with a special emphasis on P biogeochemistry

Organic farming is based on the natural cycles of energy and nutrients, and relies on the use of crop rotations, crop residues, compost and green manure. The International Federation of Organic Agriculture Movements (IFOAM) agrees to define the “Organic agriculture as a production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects".
This Scientific Session invites you to contribute with your experience in organic farming in relation to soil changes (biota, water, mineral and organic matter, erosion), soil productivity, plant protection, healthy food, food quality or socio-economic aspects. Studies focused on optimal energy efficiency, carbon and water footprint (with an emphasis in green and grey water), greenhouse gasses (GHC) and soil nutrient balancing as indicators of sustainable agricultural practices, are also welcomed. Research conducted on different continents will be shown in order to know the sustainability of organic agriculture under different environmental, social and economic conditions. All these studies could provide robust scientific basis for governmental agricultural policies development and decision tools for stockholders.

Fundings provided by INIA (Spanish National Institute for Agricultural and Food Research and Technology), Spanish Ministerio de Ciencia e Innovación (MICINN) and Ministry of Education, Culture and Sports (Castilla-La Mancha, Spain).

Convener: Marta María Moreno Valencia | Co-conveners: Jaime Villena, Manfred Sager, Tonu Tonutare, Viia Lepane
Presentations
| Thu, 26 May, 08:30–11:05 (CEST)
 
Room D3

Session assets

Session materials

Presentations: Thu, 26 May | Room D3

Chairperson: Manfred Sager
08:30–08:38
08:38–08:48
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EGU22-2713
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solicited
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Highlight
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On-site presentation
Maria Vincenza Chiriacò

One of the most well-known and appreciated characteristics of organic food is the lower pesticide residual which reduces the risks for human health. Moreover, the main benefit clearly recognized to the organic farming is the environmental sustainability compared to conventional ones, with a minor pressure of chemicals, reduced negative impacts on biodiversity and water quality and improved agricultural soil and vitality. However, the effect of organic farming on global warming and climate change mitigation is instead a still open debate in the scientific community. Depending on the boundary of the study, the adopted methodology, the soil and climatic characteristic of the agrosystem, the analyzed crops and the availability of primary data, different studies in literature provide diverse and even opposite results: organic farming is considered to perform better in some cases and worse in other cases in terms of contribution to climate change, compared to conventional farming.

The carbon footprint (CF) is one of the most used indicators to measures the contribution to climate change in terms of GHG emissions with different metrics (e.g. GHG per unit of product or per unit of land). With the aim to contribute to a more informed debate on the actual contribution to climate change in terms of GHG emissions of organic and conventional agriculture, we carried out a systematic analysis of the existing peer-reviewed studies allowing an unbias comparison of product-based vs land-based CF.

The results of the review show that organic food has on average lower impact on climate than conventional ones both when the CF is assessed per area unit (-43% GHG emissions, average) and per product unit (-12% GHG emissions, average), solving the existing scientific debate in favor of the organic food production, being more sustainable both in terms of total climate altering gases released in atmosphere and in terms of GHG emission intensity per product.

According to these results and in view of the global climate policies’ targets which foster organic food production and the transition to sustainable diets, a potential full conversion of the actual global croplands into organic lands would nearly halve the emissions from the land sector, from the current 11 GtCO2eq yr–1 to 6 GtCO2eq yr–1.

How to cite: Chiriacò, M. V.: Organic versus conventional food emissions under different carbon footprint metrics, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2713, https://doi.org/10.5194/egusphere-egu22-2713, 2022.

08:48–08:54
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EGU22-973
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Presentation form not yet defined
Galyna Medyna and Elena Valkama

Background: The EU’s Farm to Fork strategy sets the objective of reaching “at least 25% of the EU’s agricultural land under organic farming by 2030” and Finland is still below that threshold. We set out to estimate the expected GHG emissions were the local organic cereal production be increased to 25%.

Methods: EX-Ante C-balance Tool (EX-ACT) was chosen for the assessment. It is a freely available spreadsheet-based approach developed by the FAO, aiming to provide a cost-effective calculation of the impact of agricultural, forestry and fishery projects on carbon-balance. EX-ACT can be used by solely providing data on project activities and relying on recognized default values for emission factors and carbon values (Tier 1) to calculate GHG emissions. Result precision can be increased through region-specific values (Tier 2), if known and available. The choice of using EX-ACT for the case study was two-fold: (1) to see the appropriateness of its Tier 1 results, and (2) to showcase a use for ARMOSA model results for Tier 2 refinement [the model is presented in a separate abstract].

5-year average statistical data was used for harvest areas and yields. Other input values (e.g chemical inputs, machinery use) were based on experimental and literature data. Estimates were calculated for  “business-as-usual” (organic production in Southeast Finland and South Savo ELY-centers are 15.3% and 18% of the arable land, respectively), Scenario 1 (overall cereal production area identical, i.e., 75,000 ha, increase to 25% organic production, conventional and organic yields remain the same), and Scenario 2 (as Scenario 1, but organic yields are increased by 10%).

Results: Tier 1 results (that use default values for e.g. rates of soil C seq.) estimate that currently all cereal production in the project area results in soil C sequestration, from field to farm gate (from field preparation to chemical fertilizer production to planting and harvesting). “Business as usual” resulted in -0.1 tCO2eq/ha/yr, Scen. 1 and 2 both -0.4 tCO2eq/ha/yr. This is largely due to the broad management practice categorisations that EX-ACT makes to stay cost-effective and with low data requirements resulting in underestimated CO2 emissions from organic soils.

Tier 2 results estimate that the soil C sequestered by organic fields does not fully compensate emissions originated from the use of fertilizers, fuel, etc. in the studied area. “Business as usual” resulted in +1tCO2eq/ha/yr emitted, while Scen. 1 and 2 both +0.6tCO2eq/ha/yr. These results are in line with previous LCA studies showing that organic practices can lower emissions but are not sufficient to achieve neutrality by implementing EU’s Farm to Fork strategy.

Acknowledgements: This work is as part of the EFSOA project Environmentally Friendly Smart Organic Agriculture (KS 1798), South-East Finland-Russia Cross-Border Cooperation Programme, funded by the EU, the Russian Federation, and the Republic of Finland (https://efsoa.ru/engmain).

How to cite: Medyna, G. and Valkama, E.: Shifting towards more organic cereal production: estimation of expected GHG emissions in Southeast Finland and South Savo using EX-ACT, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-973, https://doi.org/10.5194/egusphere-egu22-973, 2022.

08:54–09:00
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EGU22-2269
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Highlight
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On-site presentation
Elena Valkama, Alessia Perego, and Marco Acutis

In Finland, nitrate (N) leaching loss and soil organic carbon (SOC) decrease are current environmental threats. The aim of the study is to simulate soil C dynamic and N leaching loss for conventional (C) and organic (O) farming systems producing either crops or livestock in South Savo (Finland). Simulations were carried out by using the process-based model ARMOSA for both current (1999-2018) and near future climate scenarios (2020-2040, RCP 6.0: annual change + 0.8 °C, –70 mm). Daily meteorological data from Mikkeli station, and the statistical data in the region during the last 20 years served as model inputs.

Five-year crop rotations were simulated on loamy sand soil (C 3.5 %, C/N ratio 17, pH 6.2).  In crop farm, rotations included cereals (with fodder pea in the organic farm), oilseed rape and grass, while in the livestock farm, the rotation consisted of two years of cereals followed by a 3-year fescue and timothy meadow (with clover in the organic farm). In the crop farm, we simulated three conventional cropping systems: mineral fertilizer with either crop residues removed (C1–R) or incorporated into soil (C1+R), mineral fertilizer + slurry, residues incorporated (C2+R); and two organic systems: green manure (O1+R) or meat and bone meal-based commercial organic fertilizer, Ecolan Agra® (O2+R). In the livestock farm, we simulated conventional and organic cropping systems: mineral fertilizer + slurry with either residues removed (LC–R) or incorporated into soil (LC+R); slurry with either residues removed (LO–R) or incorporated (LO+R).

 The results showed that conventional crop production systems led to relevant SOC decline of 500-750 kg ha–1yr–1 at 0-30 cm soil depth, while organic systems showed either less SOC decline (120 kg ha–1yr–1) as in O1+R, or slight SOC increase (55 kg ha–1yr–1) as in O2+R. Under the future climatic conditions, the model estimated a faster degradation of SOC for all the cropping systems, except for O2+R that still resulted in a negligible SOC increase. Annual N leaching predicted to be about 10 kg NO3-N ha–1 yr–1 for conventional crop farm, while 3 kg NO3-N ha–1 yr1 for organic crop farm with green manure. Under the future climate scenario, conventional cropping systems are prone to an increased N leaching loss, up to 20 kg NO3-N ha–1 yr–1, but organic systems do not.

The simulation of livestock farm showed a loss of SOC about 25-160 kg ha–1yr–1 in LC–R, LC+R and LO–R, while a small SOC increase of 20 kg ha–1yr–1 in LO+R.  Annual N leaching loss varied between 6 and 9 kg NO3-N ha–1 yr1 with very little differences between organic and conventional systems due to use of perennial grass in rotation and slurry as N-fertilizer. In the future climate, the model forecasted an overall increase of SOC losses for all systems, and the larger N loss in organic livestock farm, up to 15 kg ha–1 yr–1.

In conclusion, the modelling results suggest that organic crop production farms can be more environmentally friendly per unit area compared to conventional farms, particularly under the future climate scenario. 

How to cite: Valkama, E., Perego, A., and Acutis, M.: Soil organic carbon and nitrate leaching loss in organic and conventional farming systems for the current and near future climate , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2269, https://doi.org/10.5194/egusphere-egu22-2269, 2022.

09:00–09:06
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EGU22-12920
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ECS
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Virtual presentation
Oka Ardiana Banaty

Soil N mineralization is a crucial parameter for efficient N management in intensive agriculture and is determined by a combination of static or inherent (mineralogy, texture) and dynamic soil properties. We measured N mineralization potential from native soil organic matter (SOM) of 21 agricultural fields under intensive management in 2018-2019 and compared these to N mineralization potential measured on the exact locations in these fields in 2009. We hypothesized that changes in N mineralization over this decadal period could be explained by differences in land management and would be reflected in soil biochemical and physical properties. The results showed that potential N mineralization assessed in 2018-2019 was higher than measured in 2009. However, the changes of N mineralization potential was not significantly correlated with pH-KCl, N total, TOC, C: N ratio and microbial activities (Cmic). Likewise, it was not significantly associated with texture (% sand, % silt and % clay). Therefore, in this study, the potential of N mineralization could be more affected by changes in land management practices (i.e. fertilization, crop rotations and soil tillage) than soil properties following ten years.

How to cite: Banaty, O. A.: Evaluation of potential nitrogen mineralization and relations to static and dynamic soil properties from arable agricultural soils following ten years in Flanders, Belgium, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12920, https://doi.org/10.5194/egusphere-egu22-12920, 2022.

09:06–09:12
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EGU22-10211
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ECS
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Highlight
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Virtual presentation
Jukka Kivelä and Elias Hakalehto

The by-products of food and forestry industry are usually considered as waste causing significant environmental problems. However, these by-products can be processed by using microbes to produce valuable chemicals as well as recycled fertilizers.

Microbial processes funded by the Finnish Ministry of Agriculture and Forestry have provided prime organic fertilizers from industrial side streams. In earlier greenhouse trial cellulosic deposits of the forest industries were upgraded with lactic acid and nitrogen-fixing bacteria providing 50% increased plant growth compared with the standard method. Another trial, the chicken manure treatment, consisted of microbiologically processed mix of manure, wood chips, and egg industry and slaughterhouse wastes. For example, this process yielded valeric acid and other valuable short-chain fatty acids (SCFA's). Simultaneously, both the methane yield and fertilizer nutritional value for the plants of the recycled residual fractions were remarkably upgraded by the microbiological treatments.

In Kasimir -project we are processing microbiologically by-products of industrial sauce production (Puljonki Oy, Nestle Professional). We get three different products out of this process: bone, fat, and protein fractions. Fat and protein fractions are processed further in biogas plant and bone fraction is processed as recycled fertilizer. In the case of microbiologically processed sauce industry wastes, the treatments with selected micro-organisms:

  • separated bone material from soft tissues
  • degraded and pulverized bones
  • eliminated and processed foam

Pulverized bones are used as component of recycled fertilizer, as they have quite a lot of plant nutrients. Total mineral contents of the organic bone meal were nitrogen (N) 3,9 %, phosphorus (P) 11 % and calcium (Ca) 22 %. Bone meal has been as a part of recycled fertilizer which has been used as fertilizer in field trials.

Besides the soil improvement, various food-grade chemicals, such as lactate and mannitol, were formed in some processes. All the microbial waste treatments produced high amounts of plant nutrients corresponding to standard mineral fertilizers but in a sustainable fashion.

Recycling food, paper and pulp industry by-products with microbiological biorefinery methods gives possibility to replace mineral oil-based materials. In addition, the microbiological nutrient recycling is more effective, and we can get more sustainable agriculture and food processing. With their accelerative effect in a bioprocess, the soil-derived microbial strains boost the agricultural circulation of substances and integrate the processing of industrial side streams into the soil ecosystem.

How to cite: Kivelä, J. and Hakalehto, E.: Utilization of microbial strains and communities as a precept of recycled organic fertilization, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10211, https://doi.org/10.5194/egusphere-egu22-10211, 2022.

09:12–09:18
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EGU22-6160
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Virtual presentation
Gerhard Soja, Anders Sörensen, Bernhard Drosg, Wolfgang Gabauer, Alexander Schumergruber, Gerald Dunst, Daniela Meitner, Elena Guillen, Markus Ortner, and Christoph Pfeifer

Biochars are well-known for their high sorption capacity of cationic substances. Whereas the pyrolysis of vegetation-based feedstock produces biochar with high carbon concentrations (70-90 %), these chars contain only very small fractions of plant-relevant macronutrients with good bioavailability. The usage of animal bones as pyrolysis feedstock, however, produces phosphorus-rich biochars (10-15 % P) that are low in carbon (10-20 % C). The deficiency in nitrogen of these bone chars can be compensated for by sorbing nitrogen prior to use them as soil improvers.

Among the different possibilities to enrich nitrogen-poor biochars with ammonium, the use of biogas digestate is one of the most promising options in terms of nitrogen recycling and reduction of gaseous nitrogen losses. Direct applications of biogas digestate may result in high ammonia losses during spreading of the liquid and in the first days after soil incorporation. The use of membrane distillation for separating digestates into an ammonium-enriched and an ammonium-poor fraction allows the use of a sorbate with up to 10 g NH4+ L-1 that can be used to enrich bone chars with easily bioavailable nitrogen.

Based on measurements of cation exchange capacity (CEC), it appears that ion exchange plays an important role in the sorption of ammonium. Bovine bone char showed higher CEC than pig bone char. Apparently, the nitrogen enrichment of bone char from ammonium sulfate solutions had increased the availability of the preexisting bone char nitrogen by acting as a mild acid. By testing the nitrogen availability of N-enriched bone chars with a standardized plant test (“Neubauer-Test”), we observed that chars enriched with the biogas digestate ammonium-rich fraction were able to significantly improve the performance of bone char-treated plants (+135 % in plant dry matter, +130 % in plant N uptake compared to non-enriched bone char). This result was achieved by using bovine ribs as pyrolysis feedstock and biogas digestate from the same abattoir that had produced the cattle bones as residues from carcass processing for food production. This case study could show that the combined use of liquid and solid abattoir wastes is able to produce an efficient organic NP-fertilizer and replacement for mineral fertilizer.

Acknowledgments: The authors are grateful to the Austrian Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology via the Austrian Research Promotion Agency (FFG: “Produktion der Zukunft”, 24th call, project nr. 864849) for financial support of the project NutriCoal.

 

How to cite: Soja, G., Sörensen, A., Drosg, B., Gabauer, W., Schumergruber, A., Dunst, G., Meitner, D., Guillen, E., Ortner, M., and Pfeifer, C.: Animal bone chars as sorbents and providers of ammonium nitrogen from biogas digestates, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6160, https://doi.org/10.5194/egusphere-egu22-6160, 2022.

09:18–09:24
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EGU22-11013
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Virtual presentation
Marta M. Moreno, Jaime Villena, Sara González Mora, Pablo A. Morales, Concepción Atance, Carlos Ortega, Antonio Ruiz-Orejón, Juan A. Campos, and Carmen Moreno

The use of hydromulches in agriculture is being investigated nowdays by different research groups in their search for harmless materials which mainly exert a reasonable weed control and allow saving crop water consumption by reducing soil evaporation, both in open field as in container nurseries. To achieve these goals, these materials would avoid, or at least reduce, the use of chemical herbicides or plastic mulches derived of non-renewable sources, with the environmental, economy and energy effect it implies, aspects clearly appreciated in organic farming. However, one of the most important problems associated to the hydromulches is their degradation process and their useful life, because, due to their organic origin, may disappear early and therefore not fulfil their function.

For this reason, in both an intensive almond crop planted in the open field and in young olive trees grown in big containers, we evaluated the evolution and disintegration process of different mixtures based on by-products derived from the agricultural sector (barley straw, rice husk, rests from mushroom production, pruning wood chips), mixed with a binder and recycled paper paste and applied in liquid form on the ground with subsequent solidification (hydromulch). For that, we focused on the evolution of the continuous formation of cracks (shape and size), thickness, puncture resistance and ground cover by the material.

In summary, and a basis for future tests, the main conclusion derived from the results is the importance of keeping the hydromulch materials as dry as possible. We have been able to verify that, when the material gets wet (either by irrigation water, or by rain or fog), it softens, thus losing its puncture resistance and disappearing early. In addition, when the material becomes wet, the attack of the fauna (rabbits, wild boars, birds, etc.) intensifies, accelerating the process of deterioration of the hydromulch installed on the field. In relation to the materials tested, the hydromulches based on rests from mushroom production undergoes strong and early disintegration, integrating completely into the soil, especially in field conditions. The best results in terms of permanence and stability throughout the trials were obtained in rice husk and pruning wood chips, which would position these mixtures as interesting alternatives especially in container crops, important for nursery crops.

Keywords: hydromulches, deterioration, puncture resistance, organic farming.

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

How to cite: Moreno, M. M., Villena, J., González Mora, S., Morales, P. A., Atance, C., Ortega, C., Ruiz-Orejón, A., Campos, J. A., and Moreno, C.: Evolution and behaviour of hydromulches in organic woody crops under open field and container conditions., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11013, https://doi.org/10.5194/egusphere-egu22-11013, 2022.

09:24–09:30
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EGU22-12877
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ECS
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Virtual presentation
Khalid Azim, Meryem Maatougui, and Rachid Bouabid

Salinity is one of the most important abiotic stresses that decrease yields of most crops around the world, especially in arid and semi-arid regions. The addition of organic amendments is one of the mitigation methods that has been tested in our experiment. In this context, we have investigated the effect of organic amendment (compost) on the green bean resilience to the water salinity in sandy and clay soils. Two levels of salinity of irrigation water (1.5 and 4 dS / m) with and without compost amendments. Most parameters measured (yield, chlorophyll, proline, content of the mineral elements) in this study were significantly influenced by the salinity levels and organic amendments. The use of compost decreased the amount of sodium in the soil and plant, even for a high salinity level. The decrease in Na+ resulted in an increase in the level of other mineral elements such as calcium, nitrogen, magnesium, and potassium. In the case of the clay soil, the addition of compost with the use of low saline irrigation water gave a higher yield (17.6%) compared to the control (without compost amendment). Increasing the salinity level of irrigation water to 4 dS / m resulted in a 43.2% reduction of the yield in the amended soil. For sandy soils, the yield was higher (10.6%) in amended soil with compost compared to the control at 1.5 dS / m level. The increase of salinity level to 4 dS / m resulted in a yield decrease of 46.7% with organic amendment and 51.8% in the absence of organic amendment. The results of this work indicate that the addition of organic matter reduces the negative effects of salinity by improving soil physic-chemical conditions, reducing salt accumulation, increasing photosynthetic pigments and the content of proline in the plant, promotes the absorption of mineral elements and decreases the effect of salt stress on vegetative growth.

Key words: Salinity, stress, organic amendment, irrigation water, green beans, yield, proline, mineral elements.

How to cite: Azim, K., Maatougui, M., and Bouabid, R.: Compost amendments to alleviate saline water stress on organic green bean (Phaseolus Vulgaris L.) cultivated in sandy and clay soils under arid climate, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12877, https://doi.org/10.5194/egusphere-egu22-12877, 2022.

09:30–09:36
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EGU22-12848
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Virtual presentation
Elias Hakalehto, Anneli Heitto, Frank Adusei-Mensah, Laura Holopainen, Reino Laatikainen, and Jukka Kivelä

Globally, the number of the so-called zero fibre sediments on the bottom of waterways is supposed to reach thousands of environmental deposits. These by-products of the industry are usually considered as waste causing significant ecological, health and urban development problems. However, these by-products can be processed to produce valuable chemicals, such as lactic acid, which is a common food additive. The residual fraction could be converted into methane biogas and biohydrogen as well as recycled fertilizers.

The construction plan for an urban area for about 25 000 dwellers has necessitated the need for the removal of about 1.5M tons of cellulosic fibre waste ("zero waste") from the lake bottom in Tampere, Finland, 2-3 km from the city centre. Microbial processes funded by the City of Tampere and the Finnish Ministry of Agriculture and Forestry were shown to produce about 9.2% of lactate during the earlier pilot studies conducted by Finnoflag Oy. The first pilot unit of 5-15 cubic meters was manufactured by Nordautomation Oy, Finland. The maximum product level was reached in about 100 hours. In the process, the UMC (Unidentified Mixed Culture) principle was applied, and the catalytic microbial strains thus derived from the up to 10-meter-thick sediment of fibrous wastes accumulated between 1913-2008 during the factory operating ashore. Until the 1960s, the side streams were placed into Lake Näsijärvi without limitations. There they formed a thick “mattress”, preserved in the cold, dark, acidic (pH 4.5) and anoxic conditions for decades. The removal of it is estimated to take 5-10 years. The bioprocessing facilities could handle the material (dry weight 10%) straight after the delivery.

At the beginning of December 2021, the City of Tampere invited Finnoflag Oy to provide additional evidence about the productivity of biorefinery technologies. We started a five-week intensive lab and field testing period. The final yield of lactate was elevated to a concentration of more than 10% in 70-80 hours starting from an enzymatically pretreated zero waste hydrolyzed overnight and preliminarily matured in lower temperatures. The starting lactate concentration of the pretreated biomass was then between 2-3.5%. Consequently, the Consolidated Bioprocessing (CBP) was performed with lactic acid bacteria and cellulolytic enzymes as the biocatalysts. The net product increase in the bioprocess was 4-5 fold. The downstream process for lactate has been preliminarily tested by the University of Tampere, and the Mälardalen University of Technology, Sweden.

The other products of the process included additional chemicals, biogas, and organic fertilizers. All biomass was converted into products which make this endeavour an example of sustainable and economically feasible ecosystem engineering industries.

How to cite: Hakalehto, E., Heitto, A., Adusei-Mensah, F., Holopainen, L., Laatikainen, R., and Kivelä, J.: Record level productivity of lactate from a century-old cellulosic deposit on the lake bottom in Tampere, Finland, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12848, https://doi.org/10.5194/egusphere-egu22-12848, 2022.

09:36–09:42
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EGU22-11446
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ECS
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On-site presentation
Ana Simoes da Mota

This study identified the most sensitive soil quality indicators to assess soil quality in the framework of a long-term application of sewage sludge (SS) and conventional mineral fertilization for rainfed cereal production in a sub-humid Mediterranean calcareous soil. The SS treatments (at different doses and frequencies were compared with a mineral fertilization (MF) treatment and with a control treatment (no fertilization). Twenty-five years after the onset of the experiment, 37 pre-selected soil physical, chemical and biological parameters were measured, and a minimum data set was determined. The indicators significantly affected by treatment and depth were selected as sensitive.

A principal component analysis (PCA) was performed for each studied depth. At 0-15 cm, three factors (F1, F2 and F3) and at 15-30 cm, two factors (F4 and F5) were identified and explained 71.5% and 67.4% of the variation, respectively, in the soil parameters. The most sensitive indicators were related to nutrients (P and N), organic matter, and trace elements (F1 and F4), microporosity (F2), earthworms’ activity (F3), and exchangeable cations (F5). Only F3 correlated significantly (and negatively) with yield. This study demonstrated soil quality can be affected in opposite directions by SS application, and that a holistic approach is needed to better assess soil functioning under SS fertilization in this type of agrosystems.

How to cite: Simoes da Mota, A.: Soil Quality Assessment after 25 Years of Sewage Sludge vs. Mineral Fertilization in a Calcareous Soil, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11446, https://doi.org/10.5194/egusphere-egu22-11446, 2022.

09:42–09:48
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EGU22-12862
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ECS
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Presentation form not yet defined
Grassroot farming governance reform and the cooperative way of knowledge exchange in rural China
(withdrawn)
Weikai Wang, Larissa Naylor, and Paul Hallett
09:48–09:54
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EGU22-6426
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ECS
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Presentation form not yet defined
Timur Nizamutdinov, Evgeny Abakumov, Evgeniya Morgun, and Azamat Suleymanov

Agricultural practices beyond the Arctic Circle are currently being actively discussed both within the Circumpolar Agricultural Association. Arctic farming has a long history, for example, research on forage and vegetable growing, which were conducted at the Yamal zonal vegetable experimental station (which located in vicinities of Salekhad city, 66.5° North latitude). This station up to the collapse of the Soviet Union gave not only scientific results for agricultural science and give indirect results in the form of constructed unique soils with more than a century of history. At present, the field is a 2-year abandoned ground covered with meadow cereal-grass vegetation.

Long-term agricultural usage of this area resulted in the formation of a unique soil profile, fundamentally different from the common soils of the region. Over almost a century of agricultural activities, there was formed a powerful (up to 30 cm) humus-accumulative (Ap) horizon. The humus-accumulative horizon is underlain by a thick (45 cm) Iron-illuvial, with placic layers horizon (Bs), which changes into sandy horizons BCg and Cg with reductimorphic spots (Soil name: Plaggic Podzol (Turbic)).

Soils of tundra of Western Siberia are normally acidic, which caused measures to be taken to regulate the acidity/alkalinity regime of the soil when it was used in agriculture, but even at present the soil of Yamal experimental station is acidic (pH H2O 4.8-5 in the topsoil). Acidity decreases down the profile to close to neutral (pH H2O 6.6) in the Cg horizon. The soil organic carbon content in the humus-accumulative horizon is up to 2%, and its stock is 6912 g/m2. In the middle and deep horizons, the carbon content highly decreases to 0.02 % in the Cg horizon.

That soil is enriched with basic nutrients; the content of mobile phosphorus in Ap horizon is up to 450 mg/kg, mobile potassium - 60 mg/kg, with peak values occurring at the lower border (20-30 cm) of the humus-accumulative horizon, indicating the presence of eluviation processes. The content of mineral forms of nitrogen is low: ammonium nitrogen - 6 mg/kg in topsoil, 2.6 mg/kg in deep horizons; nitrate nitrogen - 21.5 mg/kg in topsoil, 0.22 mg/kg in deep horizons.

Literally, a century history of science-based farming makes the soil of the Yamal experimental agricultural station unique, it deserves not only a detailed study, but perhaps even assignment of the status of a protected natural object. There are almost no such objects still left in the Arctic zone of the Russian Federation and it is critical to prevent its loss due to the growing urbanization in the Arctic region.

This paper is supported by the Ministry of Science and University Education of the Russian Federation under agreement № 075-15-2020-922

How to cite: Nizamutdinov, T., Abakumov, E., Morgun, E., and Suleymanov, A.: Physicochemical and morphological features of unique example of agrosoil in Russian Arctic, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6426, https://doi.org/10.5194/egusphere-egu22-6426, 2022.

09:54–10:00
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EGU22-5046
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ECS
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Presentation form not yet defined
Vjacheslav Polyakov and Evgeny Abakumov

The post-anthropogenic and soil cover transformations of former agricultural soils on the abandoned lands in the Russian Arctic territory are poorly investigated due to the active growth of the city complex and increasing area occupied by agricultural lands. That is lead to an increase in the area of the arable lands surrounding the polar urbanized territories. Today, most of that land allocated for agricultural needs has been abandoned or affected by other types of land use. This study aimed to investigate the abandoned lands surrounding some of the settlements in the central part of the Yamal region. The soil diversity, morphology, and chemical and agrochemical properties were investigated with special reference to the specific transformations that occur to fallow lands under permafrost-affected cryogenic-ecosystem conditions. Analysis of data show that these soils are characterized by features relating to both, previous (and existing), anthropogenic impacts and to natural processes such as cryogenic mass transfer. Based on the analysis of agrochemical properties and features of soil formation in Salekhard city and its surroundings it can be concluded that: (1) The predominance of sandy textured parent materials in the surroundings of the urbanized territories in the central Yamal region was the key reason why these locations and substrata were chosen for the organization of agricultural farms and related practices. Due to the prevalence of clayey textured parent material across the main territories of the Yamal region, agricultural practices were based on using the arable lands and are strongly localized on quaternary sands. (2) The key nutrient content in the fine earth fraction (i.e., nitrogen and potassium in the soils) can serve not only to assess soil fertility, but also reflects current changes resulting from anthropogenic impacts on the urban ecosystems. Most soil samples showed high nutrient levels. However, in some cases, a relatively high nutrient content was also found in the lower horizons, with a large amount of Al and Fe hydroxides. (3) Due to the post-agrogenic transformation of the agropodzols, the upper horizons of the profile are acidified, which has led to increased eluvial removal (leaching) of materials, yet it still shows a clear arable horizon two decades after the last agricultural use of the soil. In the future, the intensity of the eluvial processes will increase, which after 60 years can lead to a complete degradation of the arable horizon. A superimposed type of postagrogenic evolution then begins. with the formation of a complex soil profile that combines the characteristics of the natural original soil, agropodzol, and a secondary podzol, which develops on top of the agropodzol.

 

This work was supported by Federal budget of Russian Federation, grant for support for the creation and development of a World –class Scientific Center “Agrotechnologies for the Future”, project No. 075-15-2020-922

How to cite: Polyakov, V. and Abakumov, E.: Abandoned agricultural soils from the central part of the Yamal region, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5046, https://doi.org/10.5194/egusphere-egu22-5046, 2022.

Coffee break
Chairperson: Manfred Sager
10:20–10:23
10:23–10:29
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EGU22-72
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ECS
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On-site presentation
Yaniv Freiberg, Pinchas Fine, Michael Borisover, and Shahar Baram

Contradictory data exists on the impact of dissolved organic matter (DOM) from biosolids on ortho-phosphate (IP) binding to soils constituents. On the one hand, DOM contain carboxylic acid and phenolic groups who compete with IP on common adsorption sites. On the other, biosolids addition was reported to increase the adsorption capacities of some soils. This study aims to investigate the effect of DOM extracted from compost sewage sludge (most of which smaller then 1kDa) on the Langmuir sorption capacity and affinity of IP to five soils encompassing a wide range of mechanical, chemical, and mineralogical properties. It's important to note that the dominant cation in the used soils is Ca2+. Sorption experiments were conducted using two different solutions (10mM NaCl and 5mM CaCl2) with and without DOM (810 mg OC kg-1). Without DOM, in all of the montmorillonitic soils, the obtained IP adsorption capacities were higher in the 5mM CaCl2 than in 10mM NaCl solutions, with no effect on kaolinitic soils. While DOM addition to 10mM NaCl solution increased the IP adsorption capacities by 9 to 94%, in 5mM CaCl2 no effect has been observed. In 10mM NaCl, increased adsorption capacities were accompanied by a significant decrease in the adsorption affinities.

Our results show that both Ca2+ and DOM can affect IP sorption parameters of montmorillonite-dominated soil. In such soils, when the ionic strength is higher than the flocculation value of the clays, and the pH is higher than the clays' point of zero charge, face-to-face interactions lead to tactoids formation. Thus, reducing the spillover effect, and increasing the amount of free sorption sites on the clays' broken edges (as observed in the case of 5mM CaCl2 without DOM). Furthermore, when DOM is added to montmorillonite-dominated soil, it can complex with the clay's negative planer surfaces through a multitude of reactions (in our case, mostly with Ca2+ bridging) and adsorb IP. Thus, increasing the overall adsorption capacity while reducing the affinity. Both clay flocculation and complexation processes occur concomitantly. In kaolinite, isomorphic substitutions and conformational changes rarely occur. Hence, Ca2+ addition will not foster tactoid formation or DOM complexation. To conclude, DOM effect on IP sorption is not straight forward and depended on the soil and biosolids used, and the overall affect is the equilibrium of multiply reactions the occur simultaneously.

How to cite: Freiberg, Y., Fine, P., Borisover, M., and Baram, S.: Biosolids Derived DOM Increases Phosphate Adsorption in Mediterranean Soils‏, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-72, https://doi.org/10.5194/egusphere-egu22-72, 2022.

10:29–10:35
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EGU22-4855
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ECS
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On-site presentation
Ye Tian, Chupei Shi, Carolina Urbina Malo, Steve Kwatcho Kengdo, Jakob Heinzle, Erich Inselsbacher, Franz Ottner, Werner Borken, Andreas Schindlbacher, and Wolfgang Wanek

Phosphorus (P) is an essential element for all organisms, received increasing attention in global change research. Current P-related climate warming studies have mainly addressed warming effects on soil and plant P pools, but how soil P cycling processes respond to elevated temperatures has remained largely uncertain. In this study we investigated the effect of soil warming on both, soil P pools and P cycling processes (applying the 33P isotope pool dilution technique) across different soil depths (0-10 and 10-20 cm) and seasons (spring, summer, autumn) during the 15th year of soil warming (+4 °C) in a mature temperate mountain forest, in Achenkirch, Austria. Long-term warming decelerated the gross rates of phosphate (Pi) mobilization by 21%, reducing the soil Pi input. The decreased gross Pi mobilization was in part attributed to substantial losses of soil total P pools (substrates), which likely was caused by increased dissolved organic P leaching to deeper soil layers in the warming treatment. Abiotic immobilization increased in the warming treatment, due to increased sorption of Pi to iron oxyhydroxides and clay, further reducing soil Pi availability. Moreover, warming decreased biotic Pi immobilization and microbial biomass P, and as a response, microbial communities allocated more energy and nutrients into the production of acid phosphatase, indicating a strong shift in microbial carbon and nutrient allocation in response to the decreased P availability. According to linear mixed-effects models, most of the responses of the measured P pools and processes showed no interactions between warming and soil depth and/or season, indicating consistent effects of long-term soil warming on the P cycle across different soil depths and seasons. Overall, this study highlights for the first-time how long-term soil warming affects (biotic and abiotic) soil P processes and their interactions with soil P pools. Besides, it also indicates the potential of how P constraints can affect other biogeochemical cycles in response to warming.

How to cite: Tian, Y., Shi, C., Urbina Malo, C., Kwatcho Kengdo, S., Heinzle, J., Inselsbacher, E., Ottner, F., Borken, W., Schindlbacher, A., and Wanek, W.: Long-term forest soil warming decreases soil total P pools and negatively affects biotic P processes by promoting abiotic P sorption processes, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4855, https://doi.org/10.5194/egusphere-egu22-4855, 2022.

10:35–10:41
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EGU22-10836
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ECS
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Presentation form not yet defined
Enqi Xiang, Zachary DiLoreto, Shan Mugalingam, and Maria Dittrich

Phosphorus (P) in agricultural soil is an essential nutrient for plant growth. Manure application as an organic phosphorus fertilizer improves P supply to plants. Labile P from manure can be easily transported from agricultural fields through surface runoff. Excessive P fertilizer in amended soils change into more stable forms. These processes cause eutrophication of lakes. Understanding P dynamics and P compositions in manure and soils is important. This study analyzed how do the total P and bioavailable P fraction in manure-amended agricultural soils change over seasons, as well as what factors may contribute to these changes. Additionally, we tested P sorption capacity in two soils. This study was conducted with agricultural soils from Bay of Quinte area, Ontario, Canada.

 

Our results showed that the total phosphorus (TP) amount tend to decline with aging of applied manure. Soils amended by manure in 2019 summer have around 1.17 mg TP g-1 in average, while soils with manure application more than 6 years ago have approximately 0.97 mg TP g-1 in average. Compared to manure with 4.19 mg TP g-1, the TP in soils was much less indicating low P fertilization efficiency. Comparing the concentration of TP and bioavailable P among seasons, both parameters showed an increasing trend with decreasing temperature. Reduced uptake of P by plants, the limitation of mineralization, and less rain events in winter contribute to the high values of P in winter. P sorption were examined by soil incubation experiments on two soil samples with potassium dihydrogen phosphate (KH2PO4) as inorganic fertilizer. Results indicated a negative correlation between adsorbed P and added P. Even with additional geothite as an extra iron oxide-hydroxide source, the same relation was observed. It signifies that these soils have low P-sorption capacity. The abundant amount of OM and Ca from manure and soils negatively correlated to P adsorption onto iron oxide-hydroxides. The degree of phosphorus saturation (DPS) of these two soils (95.78 and 82.46%) exceeded the threshold of P saturation level in agricultural soils (80%) and explained the release of P from solid phase.

How to cite: Xiang, E., DiLoreto, Z., Mugalingam, S., and Dittrich, M.: Investigating factors impacting phosphorus dynamics and phosphate sorption capacity of manure amended soils of Ontario, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10836, https://doi.org/10.5194/egusphere-egu22-10836, 2022.

10:41–10:47
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EGU22-8521
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ECS
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Highlight
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Virtual presentation
Maya Starr, Avner Gross, and Tamir Klein

P availability to trees is often limited by local environmental soil conditions that increase its fixation to soil minerals. In certain regions, atmospheric P inputs can compensate for low soil P availability. Among atmospheric P sources, desert dust is the most dominant. However, currently, the effects of desert dust on the P nutrition and its uptake mechanisms by forest trees is unknown.  

Here we hypothesize that forest trees which naturally grow on soils with high soil P fixation capacity can acquire P from desert dust deposited on their leaves via direct foliar uptake.

We performed a controlled greenhouse experiment with 3 forest tree species. The trees were applied with desert dust directly upon their foliage. Our findings shows that direct uptake of P from desert dust can be an alternative P uptake pathway for various tree species and highlight that desert dust can serve as an important P source to forest trees.      

 

How to cite: Starr, M., Gross, A., and Klein, T.: Forest trees can acquire Phosphorus from atmospheric dust deposition directly via the foliageForest trees can acquire Phosphorus from atmospheric dust deposition directly via the foliage, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8521, https://doi.org/10.5194/egusphere-egu22-8521, 2022.

10:47–10:53
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EGU22-9623
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ECS
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Virtual presentation
Sara Martinengo, Michela Schiavon, Veronica Santoro, Daniel Said-Pullicino, Luisella Celi, and Maria Martin

The optimization of P fertilization in paddy rice fields requires an accurate estimation of soil P availability to balance rice productivity and ecosystem preservation.  While there are several generally accepted methods to evaluate P availability to crops grown in aerobic soils, the available P pool in paddy soils cannot be so easily assessed. Phosphorus cycle in paddy soils is closely linked to Fe redox wheel and conditioned by the complex interactions between soil characteristics and plant strategies to promote P uptake. The aim of this study was the identification of the method that best estimates P availability for rice plants while taking into account the complex interactions between soil (bio)geochemistry and plant responses.

Twelve representative paddy soils have been selected and analyzed for available P with different methods (calcium chloride, Olsen, Mehlich-3, anion exchanging resins, EDTA, citrate/ascorbate and oxalate). In the same soils, rice plants were grown for 60 days; during this period temporal variation of soluble P and Fe(II) in the soil solution was monitored. The plants were then harvested and the roots and shoots biomass, the P content in plant tissues, the expression of the root phosphate transporter encoding genes and the root activity of phytase and phosphatase were determined.

During the growing period, the soluble P concentration in the soil solution increased during the first 3-4 weeks, following the same trend of Fe(II), then it decreased, probably due to plant uptake and P-Fe co-precipitation. Both biomass and P concentration in the tissues were affected by soil P content. The extraction with resins was the best predictor for plant productivity and P uptake, followed by CaCl2 and Olsen extraction. The extractants involving the partial dissolution of the sorbing minerals (i.e., oxalate and citrate/ascorbate) showed a poorer, although still significant correlation with P concentration in rice plants, but a higher performance in terms of organic P. Phosphatase activity was greater than phytase in all cases; the former did not significantly differ among soils, while the latter was higher in those soils releasing more P in solution during the growing period and was correlated with P concentration in plants. In low P soils a higher expression of root transporter encoding genes was observed, particularly those at high-affinity.

Although resins, CaCl2 and Olsen extractions are confirmed as useful tools for the prediction of P availability even for paddy rice cultivation, in P-deficient soils the enhancement of enzymatic activity and the overexpression of root P-transporters increased the capacity of plant P uptake above the prediction of the chemical extractants.

How to cite: Martinengo, S., Schiavon, M., Santoro, V., Said-Pullicino, D., Celi, L., and Martin, M.: Assessing phosphorus availability to paddy rice: soil testing and plant responses , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9623, https://doi.org/10.5194/egusphere-egu22-9623, 2022.

10:53–10:59
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EGU22-10505
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On-site presentation
Tonu Tonutare, Anne Sihver, Tiina Kõster, Tõnis Tõnutare, Kadri Krebstein, and Raimo Kõlli

Phosphorus (P) is after carbon and nitrogen the third most important nutrient element for plant growth. Most of the phosphorus needed for plant development is taken up by roots from soil. Typicaly the soil total phosphorus content is from 200 up to 3000 mg kg-1, with an average of 1200 mg kg-1. Phosphorus is present in composition of organic and inorganic (35-70%) compounds depending from the soil type. Most phosphorus containing compounds belong to groups of undissolvable and heavily dissolvable compounds. Only a small proportion of phosphorus participate in soil as easily soluble form. For development the plants can use only this minor part of soil phosphorus.

For farmers it is very important to have adequate information about the resources of plant available phosphorus in soil. Therefore, for the determination of soil plant available phosphorus content,  many different methods are developed. The oldest method, which is also used nowadays in Europe is the Dyer method, developed already in 1894. Most of the methods were created in the period from 1940-s up to 1970-s. From the chemical viewpoint these methods are extraction methods, which use aqueous diluted solutions of different salts and/or acids. These methods differ also by pH of extraction solution , duration of extraction and used soil : extraction solution ratio.

In the early years of method development the main aim was to find extragent with best extraction possibilities for phosphorus extraction from soil. Due to economical reason the main aim of researches of soil analytical laboratories is to find the best extragent for simultaneous extraction of all plant macroelements (K, Mg, Ca) and also microelements (Zn, Fe, Cu, Mn, B, S) from soil with one step. Typically, in older methods the extragents were prepared from easily accessible chemicals. These chemicals are not natural components in soil and rhizosphere. Therefore the extraction process of P from soil to solution does not take place in normal rhizosphere conditions. The natural soil rhizosphere environment is imitated for P and other plant nutrient extraction in a method called H3A. This method was developed by Haney R.L and coworkers in 2006 and modified in 2017. They proposed to mimic the plant root environment by utilizing organic acids of plant root exudates to extract nutrients at ambient soil pH.

In the experiment, determination of plant available P by H3A method was investigated and comparison was made with results obtained with Mehlich 3 and AL (Egne-Riehm-Domingo) method. In the provided experiment soil samples from Estonian agriculturally used fields by H3A; Mehlich 3  and AL methods were analyzed. For detection of P in extracts the MP-AES was used. The correlation between methods was investigated and the effect of different factors (pH, texture , organic carbon) to the correlation was also investigated.

How to cite: Tonutare, T., Sihver, A., Kõster, T., Tõnutare, T., Krebstein, K., and Kõlli, R.: Plant available phosphorus by H3A, M3 and AL methods in Estonian soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10505, https://doi.org/10.5194/egusphere-egu22-10505, 2022.

10:59–11:05
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EGU22-12295
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ECS
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On-site presentation
Tõnis Tõnutare, Evelin Veinberg, Tõnu Tõnutare, Henn Raave, Alar Astover, and Avo Toomsoo

The phosphorus is an essential element for plant growth. Therefore the pools of plant available P in soil are very important. From the environmental viewpoint, the high level of easily soluble P compounds in soil is a source of risk for leaching and contamination of waterbodies. Also, problems with depleting stock of phosphatic rock ores is increasingly on the agenda.  Approximately 80% of mined phosphatic rocks are used for producing fertilizers and the peak of mining is estimated in 20-30 years. Therefore, it is very important to find other sources for phosphorus fertilizer production.
The intensive use of mineral fertilizers causes acidification in soils. To overcome the soil acidification, liming is used. Typically, limestone and chalk are used as liming agent. During several decades also many types of ashes are used for liming agriculturally used fields. In Estonia the oil shale fly ash is used as liming agent already from 1970-s. In 2020 5,1 million tons of oil shale ash as a byproduct was produced in Estonian power plants. The powdered fly ash is a troublesome material for transportation, storage and sowing. The granulation of fly ash helps to overcome these difficulties. 
To give the added value to the granulated liming agent, the plant nutrient can be mixed into source material. For modifying granulated ashes also byproducts and residues of some other processes can be used. In our research, the oil shale ash granules were modified by using different ratios of biochar and bone meal. For the comparison, wooden ash with same impurities was used. In pot experiment, different doses of fertilizer were used. The changes in plant available P and pH in soil during 12 month in soil were investigated

How to cite: Tõnutare, T., Veinberg, E., Tõnutare, T., Raave, H., Astover, A., and Toomsoo, A.: Impact of granulated mixed liming fertilizer to soil plant available P content, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12295, https://doi.org/10.5194/egusphere-egu22-12295, 2022.