Conventional wet chemical methods for the determination of soil phosphorus (P) pools, relevant fo... more Conventional wet chemical methods for the determination of soil phosphorus (P) pools, relevant for environmental and agronomic purposes, are labor-intensive. Therefore, alternative techniques are needed, and a combination of the spectroscopic techniques—in this case, laser-induced breakdown spectroscopy (LIBS)—and visible near-infrared spectroscopy (vis-NIRS) could be relevant. We aimed at exploring LIBS, vis-NIRS and their combination for soil P estimation. We analyzed 147 Danish agricultural soils with LIBS and vis-NIRS. As reference measurements, we analyzed water-extractable P (Pwater), Olsen P (Polsen), oxalate-extractable P (Pox) and total P (TP) by conventional wet chemical protocols, as proxies for respectively leachable, plant-available, adsorbed inorganic P, and TP in soil. Partial least squares regression (PLSR) models combined with interval partial least squares (iPLS) and competitive adaptive reweighted sampling (CARS) variable selection methods were tested, and the rel...
<p>... more <p>Explicit knowledge of the dynamics and spatial distribution of surface runoff, leaching and preferential flow paths in landscapes and their connections with surface water is critical for protecting the aquatic environment for inputs of sediment, nutrients, pesticides and other harmful substances. Therefore, there is a need for quantifying off-site surface runoff and the resulting transport of sediment, nutrients and pesticides to surface waters at the field scale combined with simultaneous measurements in receiving watercourses to increase our knowledge about the linkages between source areas, transport pathways and the resulting impacts on water quality in receiving water bodies. The importance of surface runoff for transport of sediment, nutrients and pesticides to surface waters have only been limited studied in Denmark even though forecasts of climate change predicts that extreme weather conditions with more intense precipitation events will increase in the future with a risk of having more frequent incidents with surface runoff from agricultural land.</p><p>In a recent project soil erosion and surface runoff risks have been modelled for the entire of Denmark on a 10 m x10 m grid scale (Onnen et al., 2019). The influence of surface runoff for transport of sediment, nutrients and pesticides to streams is measured in three carefully selected agricultural mini-catchments showing high risks for having surface runoff in the national model. Within each catchment, an edge of field monitoring site and a stream monitoring station has been established. The edge of field monitoring site consists of a flow chamber collecting surface runoff from the neighbouring field and an automatic sampler initiated at the onset of surface runoff. The edge of field station is established with communication to the stream station for starting an automatic sampler at the time of surface runoff. Selected water samples collected at the edge of field and stream station is analysed for sediment, nutrients and pesticides. A first pilot study from one of the small catchments during the winter of 2015-2016 showed that surface runoff from the field amounted to 48 mm. the loss of suspended sediment, total nitrogen and total phosphorus, respectively, 56 kg sediment ha<sup>-1</sup>, 0.29 kg N ha<sup>-1 </sup>and 0.30 kg P ha<sup>-1</sup> (Zak et al., 2019). The new edge of field and stream monitoring setup in three agricultural catchments was established during autumn and winter of 2019-2020. The first pilot results from the winter of 2019-2020 with the full monitoring programme in the three catchments have shown frequent surface runoff events and relatively high concentrations of a number of pesticides both in edge of field and stream samples.</p><p> </p><p>References</p><p>Onnen, N., Heckrath, G., Stevens, A., Olsen, P., Greve, M.B., Pullens, J.W.M., Kronvang, B. and Van Oost, K. 2019. Distributed water erosion modelling at fine spatial resolution across Denmark. Geomorphology 342: 150-162.</p><p>Zak, D., Stutter, M., Jensen, H.S., egemose, S., Carstensen, M.V., Audet, J., Strand, J.A., Feuerbach, P., Hoffmann, C.C., Christen, B., Hille, S., Knudsen, M., Stockan, J., Watson, H., Heckrath, G. and Kronvang, B. 2019. An assessment of the multifuntionality of integrated buffer zones in northwestern Europe, JEQ 48:…
Soil organic matter (SOM) is unevenly distributed in arable fields in undulated landscapes, but t... more Soil organic matter (SOM) is unevenly distributed in arable fields in undulated landscapes, but the chemical composition resulting from their turnover, transport and deposition processes is insufficiently known. Therefore, we aimed at disclosing the molecular-chemical composition of SOM in four different catenae at shoulderslope, backslope and footslope positions in arable fields in the Baltic Sea catchment, Europe. The backslope positions always had the lowest organic C-contents (Corg) (1.6…11.8 g·kg−1) and C-stocks (3.8…8.5 kg·m−2) compared to the shoulderslopes and footslopes (1.7…17.7 g·Corg·kg−1, 5.4…15 kg·Corg·m−2). In the SOM-poor backslope positions, the organic matter was characterized by relatively high proportions of carbohydrates, phenols + lignin monomers, alkylaromatic compounds, N-compounds and amides, indicating intensive microbial decomposition. By contrast, the footslopes had the largest Corg-contents (9.3…16.5 g·kg−1) and C-stocks (8.9…15 kg·m−2) in the catenae an...
Granular drainage filters may provide new innovative solutions for removing phosphorus (P) from a... more Granular drainage filters may provide new innovative solutions for removing phosphorus (P) from agricultural tile drainage water. The influence of filter sorbent properties is well recognized; however, intragranular diffusion may be critical for the P retention efficiency in drainage filters, where convective velocities are generally high. This was investigated in granular materials (Leca, Filtralite-P®, granulated Limestone, crushed Seashells, calcined diatomite earth (CDE), and poorly ordered Fe hydroxide aggregates (CFH)) with known solute transport behavior at variable flow rates. Phosphorus retention and release were investigated during continuous P loading with a constant inlet concentration of 0.3 mg P L −1 followed by a subsequent P release phase. A parallel batch sorption experiment ranked the materials according to strength of P retention CFH > Filtralite-P® > Seashells > Limestone > Leca, while CDE was a P source at low solution concentrations. Column experiments demonstrated that filters with non-equilibrium transport (CFH and Seashells) attained higher P retention rates and lower P release rates compared to filters with equilibrium flow (Filtralite-P® and Limestone). This behavior was even more pronounced as flow rate increased and was attributed to intragranular diffusion of P in CFH and Sea-shells, which would maintain concentration gradients between mobile convective water and immobile domains. This facilitated further diffusion and thus increased P retention. In addition, the release of previously retained P was limited in filters with non-equilibrium transport (<2 %) compared to the other filters (>5 %). The results demonstrated that intragranular diffusion was an important mechanism increasing P retention.
The influence and effect of biochar on soil properties has been intensively investigated, particu... more The influence and effect of biochar on soil properties has been intensively investigated, particularly in the context of its potential to sequester carbon and mitigate the effects of anthropogenic climate change. One major question that remains unanswered concerns the erodibility and fate of biochar in the landscape. Since biochar has a lower bulk-density than soil, preferential erosion of biochar is most likely. However, until now, almost no actual data on the enrichment of biochar in in the eroded sediment or the net loss from fields exist. This important gap of knowledge could have profound economic implications for farmers committed to its use, since a high net annual loss of biochar by erosion could exceed any net annual economic gain. Most importantly, any positive gain for the environment largely depends on the amount of biochar that remains within the upper soil matrix. The overall objective of this study was to explicitly investigate the erodibility of biochar, if erosion e...
Recent studies have shown the potential of biochar for improving overall soil quality including s... more Recent studies have shown the potential of biochar for improving overall soil quality including soil aggregation and structure. Erodibility is an inherent soil property that amongst others is highly dependent on soil organic matter content which affects aggregate stability and crusting during runoff events. We hypothesized that erodibility is reduced in biochar-amended soils and tested this in controlled rainfall-runoff simulations. The specific objectives of our study were (1) to compare runoff and sediment generation between a biochar and an unamended control treatment on an arable sandy loam soil and (2) to determine the effect of the biochar treatment on SOC erodibility. A field experiment with eight plots was established at Risø, Denmark, in 2011; four biochar-amended and four unamended control plots. Biochar produced from birch wood at 500 ºC was applied at a rate of 2 kg m-2, and plots had been harrowed and ploughed twice to a depth of 25 cm prior to sampling. In the laborato...
To reduce losses from agricultural soils to surface water, mitigation options have to be implemen... more To reduce losses from agricultural soils to surface water, mitigation options have to be implemented as a local scale. For a cost-effective implementation of these measures, an instrument to identify critical areas for P leaching is indispensable. In many countries, P-index methods are used to identify areas as risk for P losses to surface water. In flat areas, where losses by leaching are dominant, these methods have their limitations because leaching is often not described in detail, PLEASE, is a simple mechanistic model designed to stimulate P Losses by leaching at the field scale using a limited amount of local field data. In this study, PLEASE, was applied to 17 lowland sites in Denmark and 14 lowland sites in the Netherlands. Results show that the simple model simulated measured fluxes and concentrations in water from pipe drains, suction cups, and groundwater quite well. The modeling efficiency ranged from 0.92 for modeling total-P fluxes to 0.36 fr modeling concentrations in...
Tillage erosion had been identified as a major process of soil redistribution on sloping arable l... more Tillage erosion had been identified as a major process of soil redistribution on sloping arable land. The objectives of our study were to investigate the extent of tillage erosion and its effect on soil quality and productivity under Danish conditions. Soil samples were collected to a 0.45-m depth on a regular grid from a 1.9-ha site and analyzed for 137Cs inventories, as a measure of soil redistribution, soil texture, soil organic carbon (SOC) contents, and phosphorus (P) contents. Grain yield was determined at the same sampling points. Substantial soil redistribution had occurred during the past decades, mainly due to tillage. Average tillage erosion rates of 2.7 kg m(-2) yr(-1) occurred on the shoulderslopes, while deposition amounted to 1.2 kg m(-2) yr(-1) on foot- and toeslopes. The pattern of soil redistribution could not be explained by water erosion. Soil organic carbon and P contents in soil profiles increased from the shoulder- toward the toeslopes. Tillage translocation r...
ABSTRACT ABSTRACT Soil erosion is a complex process with multiaspects that depends on soil proper... more ABSTRACT ABSTRACT Soil erosion is a complex process with multiaspects that depends on soil properties, slope steepness, vegetation cover, rainfall intensity and management scenarios. In this regard the management of organic amendments play a decisive role in soil erosion potential. Best management practices (BMPs) were chosen to alleviate soil erodibility and acquire the soil sustainability. Recent studies showed the potential of biochar as a non-structural BMP for improving overall soil quality. Biochar is a carbon-rich compound with high porosity produced by the pyrolysis process of biomass at relatively low temperature, under field conditions is costly and time consuming. Rainfall simulation provides the possibility to quantify the effects of different management scenarios on erosion and runoff potential at a smaller scale under controlled conditions. This study investigated the short term effects of biochar application on a sandy loam soil in Denmark. The field experiment was established with eight plots (four plots with and four plots without biochar application) in 2011. The clay, silt and sand contents of these plots were within range of 9-11 g 100 g-1, 12-14 g 100g-1 and 74-79 g 100g-1 respectively. The plots with biochar were established using biochar produced from birch wood at a temperature of 500 ͦ C (74 % of particles having a size of 4-8 mm). An amount of 2 kg m-2 where applied to the topsoil and was incorporated into the soil by harrowing back and forth (one time). From each plot a representative sample with systematic sampling from 6 points (0-20 cm depth) has obtained. In the laboratory the soil samples were analysed in relation to aggregate stability and soil organic carbon (SOC) content including total organic carbon (TOC %), total inorganic carbon (TIC %) and total carbon (TC %). Soil erosional properties including erosion rate, runoff rate, runoff coefficient and total organic carbon eroded from each plot were measured during a 3½ hour rainfall simulation tests (30 minutes time interval) using a round flume setup (outside diameter of 50 cm and an inner diameter of 10 cm) having an inclination of 10 % from the outside to the inner rim. Artificial rain was applied with a specific nozzle at a rate of 30 mm h-1. Measurements showed that biochar application into the soil was able to enhance SOC and aggregate stability. Plots with biochar application, showed significantly lower runoff rate (mm h-1) and erosion rate (g m-2 h-1) compared to the control plots due to aggregating effects of organic carbon with binding agents resulting from biochar application. The sediment concentration during rainfall simulation tests was decreased for both biochar and control plots and for plots with biochar application was lower. Moreover, the runoff coefficient (RC) in plots with biochar application was lower. Enrichment ratio (the ratio of organic carbon in the sediment to the original soil) of plots with biochar was lower than control plots. Total organic carbon eroded (g) in plots with biochar application was lower than plots without biochar application. In addition the results showed that there was difference between surface pattern of plots without biochar and plots with biochar application. On the surface of soil amended with biochar there were biochar lumps as binding proxies to form the soil aggregates and caused increase the resistance of soil surface against erosive forces. The results illustrated that biochar application already in a short term can lead to an improvement of soil aggregation thereby enhancing the aggregate stability leading to a lowering of soil erosion. Key words: best management practice (BMP), erosion potential, biochar, rainfall simulator, aggregate stability, enrichment ratio (ER)
Conventional wet chemical methods for the determination of soil phosphorus (P) pools, relevant fo... more Conventional wet chemical methods for the determination of soil phosphorus (P) pools, relevant for environmental and agronomic purposes, are labor-intensive. Therefore, alternative techniques are needed, and a combination of the spectroscopic techniques—in this case, laser-induced breakdown spectroscopy (LIBS)—and visible near-infrared spectroscopy (vis-NIRS) could be relevant. We aimed at exploring LIBS, vis-NIRS and their combination for soil P estimation. We analyzed 147 Danish agricultural soils with LIBS and vis-NIRS. As reference measurements, we analyzed water-extractable P (Pwater), Olsen P (Polsen), oxalate-extractable P (Pox) and total P (TP) by conventional wet chemical protocols, as proxies for respectively leachable, plant-available, adsorbed inorganic P, and TP in soil. Partial least squares regression (PLSR) models combined with interval partial least squares (iPLS) and competitive adaptive reweighted sampling (CARS) variable selection methods were tested, and the rel...
<p>... more <p>Explicit knowledge of the dynamics and spatial distribution of surface runoff, leaching and preferential flow paths in landscapes and their connections with surface water is critical for protecting the aquatic environment for inputs of sediment, nutrients, pesticides and other harmful substances. Therefore, there is a need for quantifying off-site surface runoff and the resulting transport of sediment, nutrients and pesticides to surface waters at the field scale combined with simultaneous measurements in receiving watercourses to increase our knowledge about the linkages between source areas, transport pathways and the resulting impacts on water quality in receiving water bodies. The importance of surface runoff for transport of sediment, nutrients and pesticides to surface waters have only been limited studied in Denmark even though forecasts of climate change predicts that extreme weather conditions with more intense precipitation events will increase in the future with a risk of having more frequent incidents with surface runoff from agricultural land.</p><p>In a recent project soil erosion and surface runoff risks have been modelled for the entire of Denmark on a 10 m x10 m grid scale (Onnen et al., 2019). The influence of surface runoff for transport of sediment, nutrients and pesticides to streams is measured in three carefully selected agricultural mini-catchments showing high risks for having surface runoff in the national model. Within each catchment, an edge of field monitoring site and a stream monitoring station has been established. The edge of field monitoring site consists of a flow chamber collecting surface runoff from the neighbouring field and an automatic sampler initiated at the onset of surface runoff. The edge of field station is established with communication to the stream station for starting an automatic sampler at the time of surface runoff. Selected water samples collected at the edge of field and stream station is analysed for sediment, nutrients and pesticides. A first pilot study from one of the small catchments during the winter of 2015-2016 showed that surface runoff from the field amounted to 48 mm. the loss of suspended sediment, total nitrogen and total phosphorus, respectively, 56 kg sediment ha<sup>-1</sup>, 0.29 kg N ha<sup>-1 </sup>and 0.30 kg P ha<sup>-1</sup> (Zak et al., 2019). The new edge of field and stream monitoring setup in three agricultural catchments was established during autumn and winter of 2019-2020. The first pilot results from the winter of 2019-2020 with the full monitoring programme in the three catchments have shown frequent surface runoff events and relatively high concentrations of a number of pesticides both in edge of field and stream samples.</p><p> </p><p>References</p><p>Onnen, N., Heckrath, G., Stevens, A., Olsen, P., Greve, M.B., Pullens, J.W.M., Kronvang, B. and Van Oost, K. 2019. Distributed water erosion modelling at fine spatial resolution across Denmark. Geomorphology 342: 150-162.</p><p>Zak, D., Stutter, M., Jensen, H.S., egemose, S., Carstensen, M.V., Audet, J., Strand, J.A., Feuerbach, P., Hoffmann, C.C., Christen, B., Hille, S., Knudsen, M., Stockan, J., Watson, H., Heckrath, G. and Kronvang, B. 2019. An assessment of the multifuntionality of integrated buffer zones in northwestern Europe, JEQ 48:…
Soil organic matter (SOM) is unevenly distributed in arable fields in undulated landscapes, but t... more Soil organic matter (SOM) is unevenly distributed in arable fields in undulated landscapes, but the chemical composition resulting from their turnover, transport and deposition processes is insufficiently known. Therefore, we aimed at disclosing the molecular-chemical composition of SOM in four different catenae at shoulderslope, backslope and footslope positions in arable fields in the Baltic Sea catchment, Europe. The backslope positions always had the lowest organic C-contents (Corg) (1.6…11.8 g·kg−1) and C-stocks (3.8…8.5 kg·m−2) compared to the shoulderslopes and footslopes (1.7…17.7 g·Corg·kg−1, 5.4…15 kg·Corg·m−2). In the SOM-poor backslope positions, the organic matter was characterized by relatively high proportions of carbohydrates, phenols + lignin monomers, alkylaromatic compounds, N-compounds and amides, indicating intensive microbial decomposition. By contrast, the footslopes had the largest Corg-contents (9.3…16.5 g·kg−1) and C-stocks (8.9…15 kg·m−2) in the catenae an...
Granular drainage filters may provide new innovative solutions for removing phosphorus (P) from a... more Granular drainage filters may provide new innovative solutions for removing phosphorus (P) from agricultural tile drainage water. The influence of filter sorbent properties is well recognized; however, intragranular diffusion may be critical for the P retention efficiency in drainage filters, where convective velocities are generally high. This was investigated in granular materials (Leca, Filtralite-P®, granulated Limestone, crushed Seashells, calcined diatomite earth (CDE), and poorly ordered Fe hydroxide aggregates (CFH)) with known solute transport behavior at variable flow rates. Phosphorus retention and release were investigated during continuous P loading with a constant inlet concentration of 0.3 mg P L −1 followed by a subsequent P release phase. A parallel batch sorption experiment ranked the materials according to strength of P retention CFH > Filtralite-P® > Seashells > Limestone > Leca, while CDE was a P source at low solution concentrations. Column experiments demonstrated that filters with non-equilibrium transport (CFH and Seashells) attained higher P retention rates and lower P release rates compared to filters with equilibrium flow (Filtralite-P® and Limestone). This behavior was even more pronounced as flow rate increased and was attributed to intragranular diffusion of P in CFH and Sea-shells, which would maintain concentration gradients between mobile convective water and immobile domains. This facilitated further diffusion and thus increased P retention. In addition, the release of previously retained P was limited in filters with non-equilibrium transport (<2 %) compared to the other filters (>5 %). The results demonstrated that intragranular diffusion was an important mechanism increasing P retention.
The influence and effect of biochar on soil properties has been intensively investigated, particu... more The influence and effect of biochar on soil properties has been intensively investigated, particularly in the context of its potential to sequester carbon and mitigate the effects of anthropogenic climate change. One major question that remains unanswered concerns the erodibility and fate of biochar in the landscape. Since biochar has a lower bulk-density than soil, preferential erosion of biochar is most likely. However, until now, almost no actual data on the enrichment of biochar in in the eroded sediment or the net loss from fields exist. This important gap of knowledge could have profound economic implications for farmers committed to its use, since a high net annual loss of biochar by erosion could exceed any net annual economic gain. Most importantly, any positive gain for the environment largely depends on the amount of biochar that remains within the upper soil matrix. The overall objective of this study was to explicitly investigate the erodibility of biochar, if erosion e...
Recent studies have shown the potential of biochar for improving overall soil quality including s... more Recent studies have shown the potential of biochar for improving overall soil quality including soil aggregation and structure. Erodibility is an inherent soil property that amongst others is highly dependent on soil organic matter content which affects aggregate stability and crusting during runoff events. We hypothesized that erodibility is reduced in biochar-amended soils and tested this in controlled rainfall-runoff simulations. The specific objectives of our study were (1) to compare runoff and sediment generation between a biochar and an unamended control treatment on an arable sandy loam soil and (2) to determine the effect of the biochar treatment on SOC erodibility. A field experiment with eight plots was established at Risø, Denmark, in 2011; four biochar-amended and four unamended control plots. Biochar produced from birch wood at 500 ºC was applied at a rate of 2 kg m-2, and plots had been harrowed and ploughed twice to a depth of 25 cm prior to sampling. In the laborato...
To reduce losses from agricultural soils to surface water, mitigation options have to be implemen... more To reduce losses from agricultural soils to surface water, mitigation options have to be implemented as a local scale. For a cost-effective implementation of these measures, an instrument to identify critical areas for P leaching is indispensable. In many countries, P-index methods are used to identify areas as risk for P losses to surface water. In flat areas, where losses by leaching are dominant, these methods have their limitations because leaching is often not described in detail, PLEASE, is a simple mechanistic model designed to stimulate P Losses by leaching at the field scale using a limited amount of local field data. In this study, PLEASE, was applied to 17 lowland sites in Denmark and 14 lowland sites in the Netherlands. Results show that the simple model simulated measured fluxes and concentrations in water from pipe drains, suction cups, and groundwater quite well. The modeling efficiency ranged from 0.92 for modeling total-P fluxes to 0.36 fr modeling concentrations in...
Tillage erosion had been identified as a major process of soil redistribution on sloping arable l... more Tillage erosion had been identified as a major process of soil redistribution on sloping arable land. The objectives of our study were to investigate the extent of tillage erosion and its effect on soil quality and productivity under Danish conditions. Soil samples were collected to a 0.45-m depth on a regular grid from a 1.9-ha site and analyzed for 137Cs inventories, as a measure of soil redistribution, soil texture, soil organic carbon (SOC) contents, and phosphorus (P) contents. Grain yield was determined at the same sampling points. Substantial soil redistribution had occurred during the past decades, mainly due to tillage. Average tillage erosion rates of 2.7 kg m(-2) yr(-1) occurred on the shoulderslopes, while deposition amounted to 1.2 kg m(-2) yr(-1) on foot- and toeslopes. The pattern of soil redistribution could not be explained by water erosion. Soil organic carbon and P contents in soil profiles increased from the shoulder- toward the toeslopes. Tillage translocation r...
ABSTRACT ABSTRACT Soil erosion is a complex process with multiaspects that depends on soil proper... more ABSTRACT ABSTRACT Soil erosion is a complex process with multiaspects that depends on soil properties, slope steepness, vegetation cover, rainfall intensity and management scenarios. In this regard the management of organic amendments play a decisive role in soil erosion potential. Best management practices (BMPs) were chosen to alleviate soil erodibility and acquire the soil sustainability. Recent studies showed the potential of biochar as a non-structural BMP for improving overall soil quality. Biochar is a carbon-rich compound with high porosity produced by the pyrolysis process of biomass at relatively low temperature, under field conditions is costly and time consuming. Rainfall simulation provides the possibility to quantify the effects of different management scenarios on erosion and runoff potential at a smaller scale under controlled conditions. This study investigated the short term effects of biochar application on a sandy loam soil in Denmark. The field experiment was established with eight plots (four plots with and four plots without biochar application) in 2011. The clay, silt and sand contents of these plots were within range of 9-11 g 100 g-1, 12-14 g 100g-1 and 74-79 g 100g-1 respectively. The plots with biochar were established using biochar produced from birch wood at a temperature of 500 ͦ C (74 % of particles having a size of 4-8 mm). An amount of 2 kg m-2 where applied to the topsoil and was incorporated into the soil by harrowing back and forth (one time). From each plot a representative sample with systematic sampling from 6 points (0-20 cm depth) has obtained. In the laboratory the soil samples were analysed in relation to aggregate stability and soil organic carbon (SOC) content including total organic carbon (TOC %), total inorganic carbon (TIC %) and total carbon (TC %). Soil erosional properties including erosion rate, runoff rate, runoff coefficient and total organic carbon eroded from each plot were measured during a 3½ hour rainfall simulation tests (30 minutes time interval) using a round flume setup (outside diameter of 50 cm and an inner diameter of 10 cm) having an inclination of 10 % from the outside to the inner rim. Artificial rain was applied with a specific nozzle at a rate of 30 mm h-1. Measurements showed that biochar application into the soil was able to enhance SOC and aggregate stability. Plots with biochar application, showed significantly lower runoff rate (mm h-1) and erosion rate (g m-2 h-1) compared to the control plots due to aggregating effects of organic carbon with binding agents resulting from biochar application. The sediment concentration during rainfall simulation tests was decreased for both biochar and control plots and for plots with biochar application was lower. Moreover, the runoff coefficient (RC) in plots with biochar application was lower. Enrichment ratio (the ratio of organic carbon in the sediment to the original soil) of plots with biochar was lower than control plots. Total organic carbon eroded (g) in plots with biochar application was lower than plots without biochar application. In addition the results showed that there was difference between surface pattern of plots without biochar and plots with biochar application. On the surface of soil amended with biochar there were biochar lumps as binding proxies to form the soil aggregates and caused increase the resistance of soil surface against erosive forces. The results illustrated that biochar application already in a short term can lead to an improvement of soil aggregation thereby enhancing the aggregate stability leading to a lowering of soil erosion. Key words: best management practice (BMP), erosion potential, biochar, rainfall simulator, aggregate stability, enrichment ratio (ER)
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Papers by Goswin Heckrath