During freeze‒thaw cycling, aggregates undergo a dynamic change in breakdown‒formation (turnover), however, how the turnover occurs between aggregates of various particle sizes is not clear. To clarify the influence of freeze‒thaw cycling on the dynamic changes in the particle size of soil aggregates, soil aggregates from the Black Soil Region of Northeast China were selected as the research objects. The study conducted in situ dynamic monitoring experiments, innovatively applying the rare earth oxide (REO) tracer method to natural conditions of freeze‒thaw cycles (autumn freeze‒thaw period, freezing period, and spring freeze‒thaw period), accurately tracking the turnover paths and quantifying the turnover rates between aggregates of various particle sizes. The results revealed that the total value of the formation paths of the 2–5mm aggregates and 0.25–2 mm aggregates increased during the autumn freeze‒thaw period. The number of freeze–thaw cycles and accumulated snowfall were significantly positively correlated with aggregate stability, with an increase in the number of freeze–thaw cycles and accumulated snowfall resulting in an increase in the proportion of aggregates >0.25 mm, which improved aggregate stability. In addition, the total value of the breakdown path of macro-aggregates increased during the spring freeze‒thaw cycling period. Soil moisture was significantly negatively correlated with aggregate stability, with increased soil moisture resulting in a decrease in the percentage of aggregates >0.25 mm, which resulted in a decrease in aggregate stability. The study can provide a reference understanding for the effects of freeze‒thaw cycles on the structure of black soil and provide a theoretical basis for improving the quality of arable land.

How to cite: Zhang, Y.: Impact of freeze–thaw cycling on the stability and turnover of blacksoil aggregates, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4011, https://doi.org/10.5194/egusphere-egu25-4011, 2025.

[Aims] Apple–soybean alley cropping is one of the typical alley-cropping models in the Loess Plateau of China. The study aimed to alleviate interspecific competition intensified by the growth of fruit trees using the combination of drip irrigation emitter line and mulching to regulate soil nutrient distribution and analyze effects on nutrient utilization. 
[Methods] A three-year field trial was conducted in apple–soybean alley-cropping systems, setting up three drip irrigation emitter line spacings (L1: one emitter line per soybean row; L2: one emitter line for every two rows; L3: one emitter line for every three rows) and two mulching methods (M1: mulching; M0: non-mulching). 
[Results] Rapidly available phosphorus (AP), rapidly available potassium and total phosphorus contents varied greatly at the same spacing, whereas AP content varied greatly at different spacings. Compared with M0, yield, nutrient contents and use efficiency of M1 significantly increased. Most of the nutrients at the denser spacing (L1) were concentrated in the surface layer with uniform distribution. At the wider spacing (L3), nutrient distribution was uneven, resulting in fewer nutrients uptake and utilization by roots. The moderate spacing (L2) with mulching alleviated the interspecific competition by optimizing nutrient distribution and facilitating root niche separation between trees and crops. In the three years, M1L2 consistently displayed the highest yield, nutrient contents and utilization efficiency. Principal component analysis showed that M1L2 achieved the highest comprehensive score. 
[Conclusions] The results recommended the use of M1L2 in young apple–soybean alley-cropping systems, with L1 as a preferable control measure if M0 is used.

How to cite: Zheng, H., Wang, R., Wan, Q., Wang, L., and Chen, L.: Nutrient distribution and utilization in apple–soybean alley-cropping systems under different drip irrigation emitter line deployments and mulching methods in the Loess Plateau of China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5740, https://doi.org/10.5194/egusphere-egu25-5740, 2025.

Abstract: To explore the spatial distribution characteristics of soil physical properties and soil erosion in sloping farmland with ridges in the black soil areas of northeast China, the slope farmland with ridges built with woven bags (RW) along the contour lines was selected as the research object, and the slope farmland was selected as a control (CK). Soil samples were collected from both RW and CK at uniform spatial intervals to measure key indicators of soil properties in the surface layer (0-15 cm), including soil water holding capacity, soil structure, and annual average soil loss (A). The results showed that: (i) RW exhibited a significantly higher overall field water-holding capacity compared to CK, with soil moisture characteristics more evenly distributed spatially. Soil bulk weight, fractal dimension and soil aggregate destruction in RW were reduced by 1.09%, 0.65% and 4.61%, respectively, compared to CK. Additionally, soil total porosity, capillary porosity, mean weight diameter (MWD), and geometric mean diameter (GWD) were more evenly distributed spatially in RW. (ii) On the up-slope, soil water content and DR_>0.25 in the RW had higher increase than those of the CK. On the mid-slope, soil field water holding capacity, capillary porosity, MWD and GWD in the RW had a higher increase than those in the CK. On the down-slope, RW had a 7.67%-10.79% increase in soil water content, saturated water holding capacity, field water holding capacity, and capillary water holding capacity compared to CK, with total soil porosity and soil capillary porosity increasing by 2.84% and 15.51%, respectively. (iii) Annual average soil loss (A) of RW was reduced by 61.85%~99.64% compared to CK, based on the China Soil Loss Equation (CSLE). (vi) Soil water-holding capacity and soil structure characteristics of the RW showed benefits compared to the CK, with the benefits ranging from 1.01 to 1.09, while the benefit of A reached 2.46. This study is significant for understanding the spatial distribution of soil erosion on slope farmland in black soil areas and for the effective application of soil and water conservation measures.

How to cite: Wei, S. and Fu, Y.: Characteristics of soil physical properties and spatial distribution of soil erosion on ridge-slope farmland in the black soil areas of Northeast China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3988, https://doi.org/10.5194/egusphere-egu25-3988, 2025.

Abstract: [Objective]To investigate the impact of intermittent rainfall on the amount and sorting characteristics of black soil splash erosion, [Methods] This study is based on artificial simulation of rainfall, with two rainfall intensities (40mm/h and 70mm/h) designed. Five rainfall events were conducted for each rainfall intensity to analyze the splashing erosion amount and particle size distribution characteristics of black soil under different rainfall conditions. [results] Under two different rainfall intensities, there is a dynamic development process of alternating strength between no crust, weak crust, strong crust, weak crust, and new crust in the topsoil crust of different rainfall sites. Under two different rainfall intensities, the maximum values of splashed aggregate MWD and GMD appeared in the fourth rainfall, and the minimum values appeared in the first rainfall. The agglomerates with a particle size of 5-2mm did not migrate in each rainfall, and the splashed agglomerates were mainly composed of particles with a size of 2-0.25mm, accounting for 36.49%~58.61% and 49.10%~60.09% of the splashed erosion amounts of the two rainfall intensities, respectively. The erosion amount of the five rainfall events showed a trend of first increasing and then decreasing with the decrease of particle size, while the mass percentage with particle size<0.053mm showed a trend of first decreasing and then increasing with the increase of intermittent frequency. The mass percentage with particle size<0.053mm all showed the minimum value in the third rainfall event, which was 18.21% and 17.63%, respectively.[Conclusion] Rainfall can lead to the formation of soil crust, and the thickness of soil crust shows dynamic changes with the increase of rainfall frequency. In the third rainfall, the soil crust thickness is the highest, and at this time, the splash erosion amount has the minimum value, mainly greater than 0.053mm. The research results provide reference for the study of soil water erosion mechanism in the black soil area of Northeast China.

Keywords: intermittent rain; Black soil; aggregate; erode

How to cite: Zhang, X.: Sorting Characteristics of Black Soil Splash Erosion Aggregates under Intermittent Rainfall Conditions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3983, https://doi.org/10.5194/egusphere-egu25-3983, 2025.

Soil water and heat are critical factors for the sustainable development of alley cropping systems in the Loess Plateau, west Shanxi, China. Experiments were conducted from 2021 to 2023 to explore the impacts of water and heat coupling regulation on crop root distribution, physiological growth, and the interrelationships between soil water and heat. The treatments consisted of three irrigation upper limit levels, set at 50% (W1), 65% (W2), and 80% (W3) of field capacity for the top 0–60 cm soil layer, and two film mulching durations: from soybean sowing to the podding stage (M1) and throughout the entire growth period (M2). Additionally, three non-irrigation control groups were included: CK0 (no mulch), CK1 (film mulching from branching to podding stage), and CK2 (full-period film mulching). In years with ample rainfall (2021 and 2023), half-period mulching was found to effectively preserve soil water compared to full-period mulching, resulting in higher underground interspecific competition coefficient; conversely, in the drier year of 2022, full-period mulching proved more effective at retaining soil water, with a lower underground species competition coefficient observed. Elevated soil moisture increased root length density (RLD) across species, intensified belowground interspecific competition, and consequently reduced soil temperature. The underground interspecific competition index initially increased and then gradually decreased as irrigation levels rose, with the peak intensity of competition occurring at the W2 irrigation level. Principal component and multiple regression analyses indicated that a water input range of 1015.63–1093.75 m³·ha⁻¹·a⁻¹ combined with half-period mulching was most advantageous during the initial 3–5 years of the alley cropping system under local production conditions.

How to cite: Wang, L., Wang, R., and Luo, C.: Characteristics of soil water and heat, physiological growth and interspecific competition in apple–soybean alley cropping for different water and heat coupling on the Loess Plateau, China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5599, https://doi.org/10.5194/egusphere-egu25-5599, 2025.

Abstract: [Objective]To investigate the effects of intermittent rainfall conditions on pore structure and aggregate turnover in the black soil topsoil. [Methods]Black soil topsoil was selected as research object, using a combination of rare earth element tracer method + artificial rainfall simulation + CT scanning research method. To elucidate the response of topsoil aggregate characteristics, turnover characteristics of topsoil aggregates, and topsoil pore characteristics to rainfall intensity and number of rainfall events. [Results]Under intermittent rainfall conditions, isolated pores are concentrated in the topsoil layer. With the increase in the number of rainfall events, the connected porosity was always greater than the isolated porosity at a rainfall intensity of 40 mm/h, and the maximum values of connected porosity and isolated porosity alternated at a rainfall intensity of 70 mm/h. For large aggregates, as the number of rainfall events increases，when the connecting porosity decreases，the ability of 5-2 mm aggregates to break up into 0.25-0.053 mm aggregates becomes smaller, and the ability of 5-2 mm aggregates to break up into <0.053 mm aggregates increases . The opposite was true when the connectivity porosity increased. For small aggregates, as the number of rainfall events increases，the ability of 0.25-0.053 mm aggregates to break into <0.053 mm aggregates is stronger, while the ability of <0.053 mm aggregates to aggregate to form 0.25-0.053 mm aggregates decreases gradually. [Conclusion]With the increase in the number of intermittent rainfall, isolated pores were concentrated in the soil top layer, while the ability of large aggregates to gradually break up into small particle sizes gradually increased, but the ability of small aggregates to form large aggregates gradually decreased.

Keywords：intermittent rainfall；pore structure；aggregate turnover；rare earth element；CT scanning

How to cite: Lei, H.: The Influence of Intermittent Rainfall Conditions on the Pore Structure and Aggregate Turnover of Black Soil Topsoil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3996, https://doi.org/10.5194/egusphere-egu25-3996, 2025.

Soil erosion can cause the dispersion and breakdown of soil aggregates. One key indicator of soil erosion resistance is soil anti-scourability. In black soil regions, the surface soil of cultivated land is particularly vulnerable to the scouring effects of runoff. This runoff can further break down and disperse soil aggregates. Therefore, studying the soil's anti-scourability, as well as the erosion characteristics of soil aggregates of different particle sizes in the surface soil of black soil cultivated land, is essential. To investigate the anti-scourability and aggregate loss characteristics of surface soil in cultivated land of the black soil area, the undisturbed soil (0-6 cm) was taken as the research object. The relationships between soil anti-scourability coefficient, scouring duration, scouring amount, and soil aggregate loss characteristics were explored, with 5 scouring amounts (6, 12, 18, 24, and 30 L/min) under indoor simulated runoff scouring experiments. The aim was to reveal the anti-scourability of the surface soil and the impact of runoff scouring on aggregate loss characteristics in cultivated land of the black soil area. 1) Overall, the total amount of soil loss gradually increased with the increase of scouring amount. The total amount of soil loss at a scouring amount of 18 L/min was 1.50 times that of 6 L/min. The soil loss decreased exponentially with decreasing scouring duration. 2) Under the conditions of scouring amounts of 6, 12, and 18 L/min, the soil anti-scourability coefficient increased as a power function with scouring duration. The soil anti-scourability coefficient was highest at a scouring amount of 18 L/min within 15 minutes, which was 2.01 and 1.38 times that at 12 and 6 L/min, respectively. 3) The loss characteristics of soil aggregates were differently affected by the scouring amount. Overall, the stability of soil aggregates gradually decreased with the increase of scouring amount, and the mass percentage of < 0.25 mm aggregates gradually increased. Conversely, the mass percentage of > 2 mm aggregates gradually decreased. The fraction size of 0.5-1 mm aggregate was the main lost fraction size under different scouring amounts, accounting for 26.84%-29.66%. 4) Compared to before runoff scouring, the mass percentage of <0.25 mm aggregates under the scouring amounts of 6, 12, and 18 L/min increased by 2.49, 14.17, and 4.18 times, respectively. 5) The erosion resistance of soils gradually decreased as the scouring amount increased. The fractal dimension of soil aggregates at a scouring amount of 18 L/min was 1.05 times that of 6 L/min. The total amount of soil loss in the surface soil of cultivated land of the black soil gradually increased with the increase of scouring amount. At the same time, the soil anti-scourability became stronger and the stability of soil aggregates gradually decreased. Additionally, the erosion resistance of soil under the 3 scouring amounts was ranked as 6 > 12 > 18 L/min. The research results provide insights into the changes in the surface soil anti-scourability in cultivated land of black soil and offer references for agricultural land use.

How to cite: Yan, J. and Fu, Y.: The surface soil anti-scouribility and aggregate loss characteristics in cultivated land of the black soil area, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3973, https://doi.org/10.5194/egusphere-egu25-3973, 2025.

Gully erosion poses greater threat to ecological and food security globally. The gully development rate and the contributions of primary influencing factors have not been thoroughly understood, primarily due to the complicated environmental conditions characterized by climate, soil, topography, and human activities. Therefore, this study was conducted to explore the gully development and contributions of its driving factors from 2013 to 2021 based on historical Google Earth images and field investigation in a typical rolling hilly watershed of northeast China. The climatic factors reflected by precipitation, topographical factors related to gully, and anthropological factors reflected by tillage ridge orientation and linear anthropological factors (LAF) including roads and shelterbelts were obtained. The tillage effect index (TEI), LAF effect index (LEI) and the distance from gully to LAF (D_L) were calculated to analyze the influence of anthropological factors on gully development. The results showed that the linear, areal and volumetric gully development rates (R_L, R_A and R_V) showed great variabilities in different periods with the average of 5.69 m year^-1, 137.37 m² year^-1 and 428.54 m³ year^-1, respectively. The accumulated R_L, R_A and R_V increased exponentially or linearly with accumulated precipitation amount (P), erosive rainfall duration (RD), erosive rainfall (ER), maximum 30-min rainfall intensity (I30) and rainfall erosivity (RE) increased (P<0.001). The slope of the gully head (HS) was identified as the primary topographic factor influencing R_L. Both R_A and R_V showed positive power relationships with the drainage area of the gully (CA) and the upstream gully head (HA). The human activity reflected by tillage ridge orientation, unpaved road and shelterbelts had different effects on R_L and R_A. The increased orientation angle between gully and tillage ridge (ROA) mitigated headcut retreat for normal precipitation year but it would aggravate headcut retreat in the periods of continuous heavy rainfall. Gully bank with the ROA of 30 - 90° was more prone to areal development. The TEI, LEI and D_L had significantly positive linear, power or exponential relations with gully development rates. The PLSR and VPA analysis indicated that topography, the interaction between topography and human activity, and the coupled effects of precipitation, topography and human activity were the main contributor of R_L, R_A and R_V, respectively, and accounted for 34%, 50%, and 40% of total variability of R_L, R_A and R_A, respectively. This study can provide guidance for the control of gully erosion and the optimization of land use structure in the gully catchment.

How to cite: Liu, X.: Quantifying the contributions of precipitation, topography and human activity and their coupling to the development of permanent gully, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4655, https://doi.org/10.5194/egusphere-egu25-4655, 2025.

Soil aggregate stability and erodibility reflect soil resistance to erosion. Although the factors influencing soil aggregate stability and erodibility have been extensively studied, the driving effects of these factors and their interactions remain limited. 184 sampling sites were selected in topsoil (0-20 cm) of a small watershed (1.42 km²) in a Mollisol watershed to measure soil bulk density (BD), soil porosity (SP), soil moisture content (MC), soil organic carbon (SOC), total nitrogen (TN), >0.25 mm water stable aggregates content (WSA_{> 0.25}), mean weight diameter (MWD) and K factor. Pearson correlation analysis, semi-variance function, redundancy analysis (RDA), and structural equation model (SEM) were used to quantify the impact of environmental variables (individual and interaction) on the spatial variations of WSA_{> 0.25}, MWD, and K factor. The findings indicated that higher values of WSA_{> 0.25} and MWD are observed in the central and western watershed, while the K values tend to be lower in areas with high WSA_{> 0.25} and MWD values within the watershed. The Exponential model optimally described WSA_{> 0.25}, MWD, and K factor with C₀/(C + C₀) indicating moderate spatial dependence for MWD (39.79%) and K factor (42.86%), while strong spatial autocorrelation for WSA_{> 0.25} (7.23%). Soil properties (moisture content, silt content, and bulk density), topography (elevation, SPI, and slope), and land use contributed 46.6%, 41.4%, and 9.1% of the spatial variation in WSA_{> 0.25}, MWD, and K factor, respectively. SEM revealed that silt content, SOC, and water condition played a fundamental role in controlling the spatial variability of WSA_{> 0.25}, MWD, and K factor. Topography exerted both direct or indirect effects by coupling land use or soil properties spatially. Land use had direct or indirect effects on WSA_{> 0.25} and K factor through regulating MC, but it primarily influences MWD indirectly through impacting MC. These results could clarify the roles and influencing paths of factors controlling the spatial heterogeneity of WSA_{> 0.25}, MWD, and K factor, contributing to optimizing land management strategies.

How to cite: Wang, L.: Quantifying the contributions of factors influencing the spatial heterogeneity of soil aggregate stability and erodibility in a Mollisol watershed, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7553, https://doi.org/10.5194/egusphere-egu25-7553, 2025.

Phosphorus (P) deficiency causes yield losses in tropical regions due to the strong P sorption of tropical soils attributed to the high amount of iron and aluminium oxyhydroxides and the low pH. Novel P fertilisers such as hydroxyapatite nanoparticles (HAP-NPs) have been proposed to improve the P application efficiency. Such nanoparticles (< 100 nm) potentially have higher mobility and bioavailability in strongly sorbing soils as they interact less with sorption sites and have a more controlled P release than soluble P fertilisers.

In a diffusion experiment using tropical soil (pH 5), the P mobility of liquid and powdered HAP-NPs was investigated and compared with that of liquid K₂HPO₄ and powdered TSP, all added at an equal P dose located at the centre of a soil column. A novel sampling method using Diffusive Gradients in Thin Films (DGT) was applied that could distinguish colloidal P from dissolved P. The soil was sampled with a back-to-back pairwise system of a classic and a nano DGT. The nano DGT consists of a normal DGT but with the addition of a dialysis membrane between the diffusive membrane and the binding layer to exclude all colloidal particles. Therefore, the difference in DGT-P between both DGTs could be attributed to P-loaded colloids or nanoparticles.  In addition, standard soil extractions (1 mM CaCl₂ and oxalate extractions) were performed to compare with the DGT method.

After one week of incubation, colour visualisation of the gels showed that the HAP-NPs were still mobile and colloidal when applied as a liquid. In contrast, the liquid K₂HPO₄ fertiliser no longer yielded mobile P. Both powdered HAP-NPs and TSP did not yield any mobile P after one week.  Results after one month are pending, but the HAP-NPs are expected to produce more bioavailable P than K₂HPO₄ and TSP, as the HAP-NPs dissolve slower and adsorb less strongly to the soil's binding sites. These results will help to understand the fate of  HAP-NPs in a tropical soil and how they may improve P application efficiency.

How to cite: Aerts, L.: The use of hydroxyapatite nanoparticles as novel phosphorus fertilisers to enhance phosphorus mobility in tropical soils, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17569, https://doi.org/10.5194/egusphere-egu25-17569, 2025.

Soil health is essential for a well-functioning, healthy food web that is vital for sustaining agricultural productivity. Evaluating soil health involves the assessment of physical, chemical, and biological indicators that reflect the soil's capacity to support plant growth, resist degradation, and sustain ecosystem functions. Soil health is viewed as a living system that can change and improve over time with the focus on long-term sustainability and recovery. Assessing soil health can help land managers, farmers, and environmentalists understand the current condition of the soil as well as make informed decisions for long term sustainable land managements. There are common approaches used to assess soil health and ecosystem recovery such as soil quality assessment where soil quality indicators are measured. Monitoring soil quality indicators over time is an essential step, involves the use of various tests and measurements that provide data on key soil attributes.

The present work aims to assess the impacts of some of the top-ranking soil properties associated with soil health in aiming to develop an integrated indicator of soil health for stakeholders which could help deliver essential ecosystem services. Overall, 15 soil properties were selected and analysed by calculating response ratios of each indicator paired with practices. The effects of vegetation cover vs no cover, the effect of different vegetation cover and different tillage systems were compared. Over 350 topsoil and sub-soil samples were collected from the TUdi partners’ mid- and long-term experimental sites differing in climate, land use, soil type and management. Our proposed list of sensitive indicators for the topsoil layer are available phosphorus, exchangeable Ca, total nitrogen, soil carbon, soil respiration, root length density and root dry weight. For the sub-soil layer, sensitive indicators are exchangeable sodium, root length density and root dry weight. By introducing two new soil biology indicators linked to plant root traits, this raises the possibility of measuring and comparing other easily measurable root traits in future research, to provide an integrated soil health indicator for soil monitoring. Providing such an inexpensive methodology, accessible to stakeholders with minimum training, should help stakeholders assess the ability of the soil to deliver the necessary ecosystem services.

How to cite: Csilla, H., Nick, O., John, Q., Ian, D., Laura, Z., Marco, P., Octavian Puiu, C., Gunther, L., Tomáš, D., David, Z., Raquel, F., César, P., Juan Carlos, G., José, G., Iria Benavente, F., Gema, G., Peter, S., Zsofia, B., and Bela, P.: Assessing the impact of some of the top-ranking soil properties associated with soil health , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20274, https://doi.org/10.5194/egusphere-egu25-20274, 2025.

Agricultural systems are inherently complex, as they are influenced by the interlinkages between biological, physical, and chemical processes, alongside uncontrollable factors such as weather and soil conditions. To overcome these challenges, dynamic system models have emerged as indispensable tools that can be effectively implemented in precision agriculture. Such dynamic models enable the optimization of variable-rate fertilization and, consequently, enhance crop management strategies while fostering environmental sustainability.

Given the significant increase in fertilizer use over the past decades, there is an ongoing effort to enhance better nutrient management and sustainable development in agriculture within the European Union. This includes the integration of nutrient recovery technologies, such as anaerobic digestion (AD) that converts organic waste into bio-based fertilizers, helping mitigate excessive nutrient loss in Nitrate Vulnerable Zones (NVZs). Additionally, introducing circularity into the fertilizer production system offers a viable solution by replacing the traditional, emission-intensive nitrogen fertilizer production methods with innovative, low-emission alternatives. However, improper application of these pre-processed fertilizers can lead to environmental issues, such as N and/or phosphorus leaching and greenhouse gas (GHG) emissions. Therefore, it is essential to (i) select the right product with least N loss (via leaching or emissions) to the environment among selected (ammonium sulphate, pig urine, liquid fraction of digestate and mineral concentrate) pre-processed bio-based fertilizers, (ii) opt the right application techniques (injection, drag hose, spraying, etc.) available for the variable-rate fertilization, (iii) provide farmers with the best optimal rate and timing for performing precision applications under changing climate.

To address this issue, we implement the CANDY (Carbon And Nitrogen DYnamics) model in a site-specific manner. The model is applied to ongoing field experiments in maize and potato fields (2023–present) at the 3-hectare Bottelare research farm, as well as two commercial farms in Lamstraat and northwest France (2.7 and 8 hectares, respectively). Different application rates of selected bio-based fertilizers (ammonium sulphate, pig urine, liquid digestate, mineral concentrate) are simulated for soil mineral and organic nitrogen (minN, SON), soil organic carbon (SOC), nitrous oxide (N2O) emission dynamics, and validated with observed values from soil properties (e.g. NH₄/NO₃, OC, etc.) and GHG measurements (N₂O, CO₂). This provides valuable data-driven insights of potential mitigation measures regarding N losses and further can be used to inform stakeholders (i.e. farmers).

How to cite: Amangeldy, N., Meurer, K., Franko, U., Boneke, E., and Mouazen, A.: Simulating variable fertilizer application ‘rates’ of synthetic and bio-based fertilizers in potato and maize fields to optimize nutrient management and validate environmental sustainability, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1127, https://doi.org/10.5194/egusphere-egu25-1127, 2025.

Uniform and excessive nitrogen (N) fertilization practices in agriculture often lead to spatial and temporal crop variability, resulting in inefficient nutrient distribution, environmental harm, reduced orchard yields, and fruit quality. This study investigates the effects of N fertilization levels on avocado ecophysiology using advanced remote sensing (RS) techniques, focusing on the estimation of Nitrogen Use Efficiency (NUE), Leaf Nitrogen Content (LNC [% dry weight]), Plant Area Index (PAI), and Canopy Nitrogen Content (CNC [kg per tree]) to estimate crop responses to over and under fertilization. NUE was calculated as Partial Factor Productivity (PFP) of N; kg of N in harvested avocado per kg N applied. This research includes three experimental systems: (1) a lysimetric experiment at the Gilat with five continuous N fertigation treatments ranging from 115 to 1400 kg-N ha; (2) Kfar Menachem Commercial Orchard, a controlled orchard with three continuous N fertigation treatments ranging from 70 – 570 kg-N ha; and (3) Kabri Orchard, a mature commercial avocado orchard (~10 ha) with standard N application (270 kg-N Ha). Key eco-physiological parameters were measured on the ground bi-monthly in tandem with UAVs during 2022-2023. The ground measurements included nutrient uptake (in the lysimetric experiment only), LNC, stomatal conductance, chlorophyll fluorescence, and growth rates. Yield, fruit quality, and shelf-life were assessed at harvest and after cold storage and shelf life. UAV flights integrated multispectral, thermal, and LiDAR sensors. Canopy metrics, such as height, volume, PAIwere estimated on the based segmentation model, and spectral indices related to vegetative growth, were extracted and incorporated into a CNC prediction model and used to evaluate spatial-temporal variability. Random forest models demonstrated high predictive accuracy on CNC (R² = 0.94, RMSE = 0.4 kg per tree). Results revealed significant site-specific leaf nitrogen responses, with notable NUE differences (p-value < 0.05). A strong negative correlation was observed between NUE and PAI (p-value < 0.05), underscoring the importance of precise nitrogen management. This research highlights the potential of advanced remote sensing and site-specific fertilization strategies to optimize precise N use, enhance avocado yield and quality, and mitigate environmental impacts. By addressing spatial variability and leveraging predictive RS modelling, this study contributes to sustainable avocado farming practices.

How to cite: Grozdov, I., Erel, R., Baram, S., Alkan, N., and Paz-Kagan, T.: Assessing Nitrogen Fertilization Impacts on Avocado Ecophysiology: Insights from UAV-Derived Remote Sensing and Nutritional Experiments Responses, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3574, https://doi.org/10.5194/egusphere-egu25-3574, 2025.

Soil acidification and low nutrient availability are critical challenges for agriculture in East Africa, often leading to aluminium (Al) toxicity and reduced crop yields. Amending arable land with local sediments has been shown to be a promising strategy to address these issues, although responses have been variable. We investigated the effects of local sediment amendments influenced by volcanic deposits on soil pH, nutrient availability, and barley productivity in field trials conducted in Eldoret, Western Kenya in the first year and compared it to lime amendments and straw return in the second year. Plots were amended with 1% and 3% of two local sediments (from Baringo and Nakuru). The 3% Baringo amendment significantly increased soil pH (from 4.7 to 7.0), enhanced available phosphorus (P) content (from 0.01 mg g⁻¹ to 0.02 mg g⁻¹), and reduced Al availability (from 3.03 mg g⁻¹ to 2.17 mg g⁻¹), resulting in the highest barley yield of 4.7 t/ha (+1061%). In the second year, growth was strongly inhibited by drought periods, but the trends were visible again with Baringo 3%. Similarly, lime at 0.15% improved soil conditions and barley yield (0.91 t ha^-1), though less effectively than Baringo 3% (1.3 t ha^-1). Control and Nakuru, as well as straw return did not improve the soil conditions and yield significantly. These findings highlight the potential of local sediment amendments to mitigate soil acidification and enhance crop productivity, particularly through carbonate dissolution and pH elevation, though outcomes depend on sediment composition and amendment rates.

How to cite: Scherwietes, E., Six, J., and Schaller, J.: Enhancing Barley Yield and Biomass in Kenya: The Effects of Local Sediments, Lime Amendments and Straw Return, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5878, https://doi.org/10.5194/egusphere-egu25-5878, 2025.

Rainfall simulators are indispensable in soil hydrology and erosion research, offering controlled conditions to investigate water erosion. Despite their widespread use, the absence of standardized methodologies leads to variability in design and rainfall characteristics across simulators. To address this challenge, key parameters such as drop size distribution and terminal velocity, uniformity of the spatial distribution of raindrops over the sprinkled surface area (Christiansen uniformity coefficient; CU), kinetic energy (KE), and rainfall intensity are used for comparative analysis. In this study, three rainfall simulators with varying transportability, nozzle system, and raindrop generation are compared. Laser distrometers and Tübingen Splash Cups (T-cups) were used to measure rainfall characteristics and kinetic energy.

The rainfall simulators produced rainfall intensity ranging from 38 to 95 mm h-1, and CU values between 60.5% and 75.8%. Most drops (>90%) were slower than 3.4 m s-1 for all simulations. The maximum number of drops was within the 0.25 – 0.375 mm class, generally smaller than that observed in natural rain, all at 1.4-1.8 m s-1 velocity. We found kinetic energy measured by T-cups to agree with values calculated with the Thies disdrometers, confirming its pertinence in rainfall studies. However, caution is advised when applying the T-cup equation under low kinetic energy scenarios, as it tends to overestimate KE.

Furthermore, we found that portable systems have distinct lower kinetic energy characteristics than indoor systems, and notable differences do not allow for the direct comparison of measurements. However, they have distinct advantages in direct field measurements and handling. The devices’ CU ranges from 60.5 to 75.8%, which falls within the range of those presented in the literature.

This study highlights the importance of accurately characterizing rainfall parameters before soil erosion modeling. The methodologies and insights provided tools for improved assessment of soil erosion risks, particularly considering its practicality in remote areas.

Keywords: Rainfall simulators, Soil erosion, Drop size distribution, Drop velocity, Raindrop kinetic energy

Research has been supported by project TUDI (European Union's Horizon 2020 research and innovation programme under grant agreement No 101000224), technology Agency of the Czech Republic (grants 8J23DE006 and QK22010261) and Czech Technical University in Prague (grant SGS23/155/OHK1/3T/11)

How to cite: Falcao, R., Krasa, J., Neumann, M., Kubát, J.-F., Gall, C., Seitz, S., and Dostal, T.: Evaluating Compact Portable and Indoor Rainfall Simulators for the Estimation of Rainfall Characteristics in Soil Erosion Studies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6127, 2025.

How to cite: Falcao, R., Krasa, J., Neumann, M., Kubát, J.-F., Gall, C., Seitz, S., and Dostal, T.: Evaluating Compact Portable and Indoor Rainfall Simulators for the Estimation of Rainfall Characteristics in Soil Erosion Studies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6127, https://doi.org/10.5194/egusphere-egu25-6127, 2025.

The sustainable management of crops in areas at risk of soil health degradation is crucial, particularly given their vulnerability in the current context of climate change. Decision Support Tools (DSTs) designed specifically for farmers are essential for assessing risks, analyzing the impact of agricultural practices, and defining strategies to mitigate negative impacts on soil health. In response to this need, the TUdi DSTs were developed (in app and web format), integrating functionalities tailored to address different types of soil degradation processes by different approaches related to soil biology, erosion, compaction, structure, organic carbon and fertilization. These DSTs are designed to restore and enhance soil health, and to optimize the use of fertilizers at the user level.

However, in scenarios of high soil health degradation, the tool’s results often highlight negative outcomes, potentially leading to rejection in its adoption. It is therefore crucial to assess user acceptance of such tools in advance. To tackle this challenge, in-person workshops were conducted, engaging both farmers and stakeholders from the agricultural sector. These workshops enabled the evaluation of the TUdi DST's acceptance, and the identification of improvements aimed at optimizing its usability and fostering its broader adoption. These efforts aim to ensure that the TUdi DST becomes an effective tool for supporting farmers in sustainable soil management, while contributing to the mitigation of climate change impacts on vulnerable agricultural systems.

Acknowledgments: this work was supported by the research project TUdi (Horizon 2020, GA 101000224).

How to cite: López Gonzalez, M.-L., Pareja, E., Benavente-Ferraces, I., Osann, A., Sánchez, J., Dostal, T., Krasa, J., Falcão, R., Zavattaro, L., Strauss, P., Carl Liebhard, G., Gómez, J. A., Guzmán, G., Domenech, I., Hudek, C., Bakacsi, Z., Nikolov, D., and Zhang, X.: TUdi Decision Support Tool to assist farmers in soil health management, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12364, https://doi.org/10.5194/egusphere-egu25-12364, 2025.

Soil erosion is a major challenge in agriculture, leading to land degradation, reduced fertility, and water pollution. Effective land management is crucial for controlling runoff, limiting sediment transport, and sustaining soil productivity. Among various conservation practices, vegetative buffer strips are particularly effective, enhancing infiltration, slowing runoff, and trapping sediment.

This study assessed the impact of different grass strip lengths on sediment retention under controlled conditions. Experiments were conducted on plots with varying proportions of grass cover (0%, 25%, 50%, and 100%). A suspension of water and fine sand was used to simulate runoff with high sediment concentration. Flow rates and experiment duration were standardized for comparability.

The results demonstrated that longer grass strips significantly reduced both surface runoff and sediment transport. Runoff was reduced by up to 29%, while sediment loads decreased by up to 85% compared to bare soil. These findings highlight the potential of vegetative barriers as an effective nature-based solution for sustainable land management.

Acknowledgements: Research has been supported by project TUDI (European Union's Horizon 2020 research and innovation programme under grant agreement No 101000224) and SGS23/155/OHK1/3T/11: Experimental research and monitoring of rainfall-runoff and erosion processes on agricultural soils. 

How to cite: Vrana, M., Laburda, T., N. R. Falcão, R., Jachymova, B., Zumr, D., Krasa, J., Tejkl, A., Kubát, J.-F., Bauer, M., and Dostal, T.: Mitigating Soil Erosion and Runoff through Vegetative Barriers in Agricultural Areas, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9549, https://doi.org/10.5194/egusphere-egu25-9549, 2025.

Many regenerative agriculture practices (RAP) such as not tillage (NT), cover crop (CC), perennials and agroforestry (AF), organic farming (OF) have potential to limit negative environmental outcomes while enhancing soil health and sustaining diverse ecosystem services. However, the magnitude by which yield responses of different RAP are influenced by inherent soil properties, climate and topographical factors are not fully understood. To elucidate such interaction, field scale experiments related to these RAP were first collected across the globe by combining multiple meta-analyses and the  yield response was extracted and then linked with global gridded soil, climate and topographical datasets. The findings showed that the RAPs were associated with an overall mean crop yield increase of 5 % with specific increase in crop yield by 48 %, 21 % and 0.28 % respectively for AF, CC and NT while a decrease of 2 % was recorded for OF. The use of RAPs had the greatest yield benefit in tropical, arid and temperate climates and when farming at mid to high elevation areas as well as in soils with low soil organic carbon. Specifically, increase in crop yield occurred consistently for AF, CC and NT in environments located in semi-arid area with aridity index between 0.20 and 0.50 and at elevation between 250 and 1000 m as well as in soils characterized by low soil organic carbon (< 5 g/kg). In addition, NT was associated with increase in crop yield especially when N input was considered in addition to cover crop and weeding in arid and tropical regions. Under the RAPs considered, cereal crops such as maize, rice and soybean resulted in significant crop yield increase especially for growing degree days within 4 000 to 10 000 degrees C. The findings shed new light on the ways in which soil characteristics, climate and topography in relation to RAPs interact to affect crop yield and such results can assist in the development of useful, fact-based recommendations for applying these practices to improve crop yields.

How to cite: Hounkpatin, O., Piipponen, J., Jalava, M., and Kummu, M.: Evaluating effect size distribution of different regenerative agriculture practices across soil, climatic and topographical factors, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17537, https://doi.org/10.5194/egusphere-egu25-17537, 2025.

One of the main outputs of the TUdi project is a catalogue of strategies and measures for improving soil quality. This document (alone or in combination with other project outputs) serves farmers to find suitable methods and measures for improving the quality of their soil.

This catalogue aims to present soil restoration and fertilization strategies with feedback from stakeholders in the EU and China. The catalogue consists of a list of practices soil degradation processes. The processes were defined with a multidisciplinary approach by scientists from different fields (soil physics, hydrology, plant and environmental sciences, nutrient management and agronomy) and they are described individually in big detail.

A list of measures and strategies that can be used to eliminate these degradation processes is presented. For individual measures, the catalogue contains a separate chapter with a detailed description of each measure. These chapters describe the principle of the methods/measures, the conditions for their implementation and the importance of individual measures in terms of individual degradation processes. There are also references to appropriate literature at the end of each chapter.

The aim of the catalogue is to support farmers in activities leading to soil improvement. For this reason, the catalogue includes a chapter dealing with financial support tools in individual countries cooperating within the TUdi project. A separate chapter is also devoted to legislative regulations and rules related to the issue of soil degradation and protection.

Research has been supported by project H2020 – TUdi (https://cordis.europa.eu/project/id/101000224)

How to cite: Jáchymová, B., Zumr, D., Dostál, T., Falcão, R., Krása, J., and Bauer, M.: Catalogue of soil restoration and fertilizations strategies across EU and China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8544, https://doi.org/10.5194/egusphere-egu25-8544, 2025.

The growing threats to soil health, particularly in regions increasingly impacted by climate change, demands innovative, science-based solutions. Organic amendments offer a pathway for improving soil health while enhancing SOM content. Addressing these challenges requires a comprehensive approach that bridges nutrient management practices with a deeper understanding of soil organic matter (SOM) dynamics. Therefore, farmers, as key actors in this process, need operational tools that not only highlight potential risks, but also provide strategies to ensure the long-term soil productivity and resilience. To support this, the TUdi Decision Support Tool (DST) combines crop nutrient requirement assessments with SOM evolution forecasting, using nutrient inputs as a factor in modeling SOM dynamics. This DST was designed as a practical decision-support tool for farmers and land managers, enabling informed decision-making to combat soil degradation and support sustainable land management practices.

In this study, we applied the TUdi DST in highly vulnerable region to soil organic matter (SOM) loss of Europe, to evaluate cereal and woody crop management. Under favorable (SOM > 2.5%) and unfavorable (SOM < 2%) scenarios of crops growing conditions were assessed to explore tailored strategies for mitigating SOM decline and enhancing carbon sequestration.

Acknowledgments: this work was supported by the research project TUdi (Horizon 2020, GA 101000224).

How to cite: Pareja-Serrano, E., Benavente-Ferraces, I., López González, M.-L., and Zavattaro, L.: TUdi Decision Support Tool: integrating nutrient management and organic matter dynamics for sustainable soil management, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12300, https://doi.org/10.5194/egusphere-egu25-12300, 2025.