Soil, water, nutrients and soil organic matter losses by water erosion as a function of soil management in the Posses sub-watershed, Extrema, Minas Gerais, Brazil / Perdas de solo, água, nutrientes e matéria orgânica do solo por erosão hídrica em função do manejo na sub-bacia das Posses, Extrema, MG

Knowledge of the quantity and quality of the material lost by soil erosion due to soil management is a basic need to identify land management zones in catchments. The aim of this study was to investigate the influence of soil management on the quantity and quality of soil material lost by erosion in the Posses sub-watershed, Municipality of Extrema, State of Minas Gerais, Brazil. Water and sediments lost by natural rainfall erosion were sampled from erosion plots located on a Red-Yellow Argisol (PVA) under the following systems: bare soil, subsistence farming (maize/beans/pumpkin/jack-beans/fallow), degraded pasture, well-managed pasture, and reforestation set up in 2013; and in a Litholic Neosol (RL): reforestation set up in 2008, bare soil, and native forest. Ca, Mg, K, P, N and soil organic matter (SOM) contents were determined in sediment and soil samples (at 0-5 cm depth) for the determination of the runoff enrichment ratios. Management influences soil losses more so than water losses. Minor losses were found in reforestation set up in 2013 (soil); in well-managed pasture (water); and in reforestations (nutrients and SOM). These losses tend to stability with time. The general sequence of nutrient losses was N > Ca > Mg > K > P in PVA; and N > Ca > K > Mg > P in RL. Loss rates of SOM and N followed the order: bare soil > subsistence farming > degraded pasture > well-managed pasture >reforestation, in PVA; and bare soil > native forest > reforestation, in Argisol. Reforestation and wellmanagementpasture are effective conservation strategies in order to lower the erosion process in thePosses sub-watershed. Soil losses, as well as nutrients and organic matter losses were more influencedby soil management than water losses. The safeguarding native forest under Argisol is essential to theconservation of this pedoenvironment, especially in steep slopes.(AU)

O conhecimento da quantidade e qualidade de material perdido por erosão hídrica em função do manejo do solo constitui uma necessidade básica para a definição de zonas de manejo em áreas de recarga de água. O objetivo desse trabalho foi verificar a influência do manejo do solo sobre a quantidade e qualidade de material perdido por erosão hídrica na sub-bacia hidrográfica das Posses, Extrema-MG. Para isso, foram coletados água e sedimentos erodidos através de parcelas de erosão, instaladas, sob chuva natural, em Argissolo Vermelho-Amarelo (PVA) nos manejos: solo descoberto, rotação cultural (milho/feijão-de-porco/pousio), pastagens degradada e bem manejada, e reflorestamento implantado em 2013; e em Neossolo Litólico (RL) nos manejos: reflorestamento implantado em 2008, solo descoberto e mata nativa. Nas amostras de sedimentos e de solos (coletadas na profundidade de 0-5 cm) foram determinados os teores de Ca, Mg, K, P, N (NT) e de matéria orgânica do solo (MOS) e com isso, calculada a taxa de enriquecimento de enxurrada. O manejo exerce maior influência nas perdas de solo do que nas perdas de água. Menores perdas foram encontradas no reflorestamento implantado em 2013 (solo), pasto bem manejado (água) e reflorestamentos (nutrientes e matéria orgânica). Há uma tendência de estabilização dessas perdas com o tempo de implantação dos sistemas. A tendência geral das perdas de nutrientesno PVA foi NT > Ca > Mg > K > P; e no Argisol foi de NT > Ca > K > Mg > P. As taxas de perdasde MOS e NT seguem a ordem: solo descoberto > rotação cultural > pasto degradado > pasto bemmanejado > reflorestamento, no PVA; e solo descoberto > mata nativa > reflorestamento, no Argisol. Oreflorestamento e o manejo das pastagens são estratégias conservacionistas que minimizam as perdaspor erosão hídrica na sub-bacia das Posses, Extrema-MG. O manejo exerce maior influencia nas perdas de solo e de materiais a ele relacionados do que nas perdas de água. A manutenção da mata nativa sob...(AU)

Soil, water, nutrients and soil organic matter losses by water erosion as a function of soil management in the Posses sub-watershed, Extrema, Minas Gerais, Brazil / Perdas de solo, água, nutrientes e matéria orgânica do solo por erosão hídrica em função do manejo na sub-bacia das Posses, Extrema, MG

Knowledge of the quantity and quality of the material lost by soil erosion due to soil management is a basic need to identify land management zones in catchments. The aim of this study was to investigate the influence of soil management on the quantity and quality of soil material lost by erosion in the Posses sub-watershed, Municipality of Extrema, State of Minas Gerais, Brazil. Water and sediments lost by natural rainfall erosion were sampled from erosion plots located on a Red-Yellow Argisol (PVA) under the following systems: bare soil, subsistence farming (maize/beans/pumpkin/jack-beans/fallow), degraded pasture, well-managed pasture, and reforestation set up in 2013; and in a Litholic Neosol (RL): reforestation set up in 2008, bare soil, and native forest. Ca, Mg, K, P, N and soil organic matter (SOM) contents were determined in sediment and soil samples (at 0-5 cm depth) for the determination of the runoff enrichment ratios. Management influences soil losses more so than water losses. Minor losses were found in reforestation set up in 2013 (soil); in well-managed pasture (water); and in reforestations (nutrients and SOM). These losses tend to stability with time. The general sequence of nutrient losses was N > Ca > Mg > K > P in PVA; and N > Ca > K > Mg > P in RL. Loss rates of SOM and N followed the order: bare soil > subsistence farming > d

O conhecimento da quantidade e qualidade de material perdido por erosão hídrica em função do manejo do solo constitui uma necessidade básica para a definição de zonas de manejo em áreas de recarga de água. O objetivo desse trabalho foi verificar a influência do manejo do solo sobre a quantidade e qualidade de material perdido por erosão hídrica na sub-bacia hidrográfica das Posses, Extrema-MG. Para isso, foram coletados água e sedimentos erodidos através de parcelas de erosão, instaladas, sob chuva natural, em Argissolo Vermelho-Amarelo (PVA) nos manejos: solo descoberto, rotação cultural (milho/feijão-de-porco/pousio), pastagens degradada e bem manejada, e reflorestamento implantado em 2013; e em Neossolo Litólico (RL) nos manejos: reflorestamento implantado em 2008, solo descoberto e mata nativa. Nas amostras de sedimentos e de solos (coletadas na profundidade de 0-5 cm) foram determinados os teores de Ca, Mg, K, P, N (NT) e de matéria orgânica do solo (MOS) e com isso, calculada a taxa de enriquecimento de enxurrada. O manejo exerce maior influência nas perdas de solo do que nas perdas de água. Menores perdas foram encontradas no reflorestamento implantado em 2013 (solo), pasto bem manejado (água) e reflorestamentos (nutrientes e matéria orgânica). Há uma tendência de estabilização dessas perdas com o tempo de implantação dos sistemas. A tendência geral das perdas de nutrien

Soil, water, nutrients and soil organic matter losses by water erosion as a function of soil management in the Posses sub-watershed, Extrema, Minas Gerais, Brazil / Perdas de solo, água, nutrientes e matéria orgânica do solo por erosão hídrica em função do manejo na sub-bacia das Posses, Extrema, MG

Knowledge of the quantity and quality of the material lost by soil erosion due to soil management is a basic need to identify land management zones in catchments. The aim of this study was to investigate the influence of soil management on the quantity and quality of soil material lost by erosion in the Posses sub-watershed, Municipality of Extrema, State of Minas Gerais, Brazil. Water and sediments lost by natural rainfall erosion were sampled from erosion plots located on a Red-Yellow Argisol (PVA) under the following systems: bare soil, subsistence farming (maize/beans/pumpkin/jack-beans/fallow), degraded pasture, well-managed pasture, and reforestation set up in 2013; and in a Litholic Neosol (RL): reforestation set up in 2008, bare soil, and native forest. Ca, Mg, K, P, N and soil organic matter (SOM) contents were determined in sediment and soil samples (at 0-5 cm depth) for the determination of the runoff enrichment ratios. Management influences soil losses more so than water losses. Minor losses were found in reforestation set up in 2013 (soil); in well-managed pasture (water); and in reforestations (nutrients and SOM). These losses tend to stability with time. The general sequence of nutrient losses was N > Ca > Mg > K > P in PVA; and N > Ca > K > Mg > P in RL. Loss rates of SOM and N followed the order: bare soil > subsistence farming > degraded pasture > well-managed pasture >reforestation, in PVA; and bare soil > native forest > reforestation, in Argisol. Reforestation and wellmanagementpasture are effective conservation strategies in order to lower the erosion process in thePosses sub-watershed. Soil losses, as well as nutrients and organic matter losses were more influencedby soil management than water losses. The safeguarding native forest under Argisol is essential to theconservation of this pedoenvironment, especially in steep slopes.

O conhecimento da quantidade e qualidade de material perdido por erosão hídrica em função do manejo do solo constitui uma necessidade básica para a definição de zonas de manejo em áreas de recarga de água. O objetivo desse trabalho foi verificar a influência do manejo do solo sobre a quantidade e qualidade de material perdido por erosão hídrica na sub-bacia hidrográfica das Posses, Extrema-MG. Para isso, foram coletados água e sedimentos erodidos através de parcelas de erosão, instaladas, sob chuva natural, em Argissolo Vermelho-Amarelo (PVA) nos manejos: solo descoberto, rotação cultural (milho/feijão-de-porco/pousio), pastagens degradada e bem manejada, e reflorestamento implantado em 2013; e em Neossolo Litólico (RL) nos manejos: reflorestamento implantado em 2008, solo descoberto e mata nativa. Nas amostras de sedimentos e de solos (coletadas na profundidade de 0-5 cm) foram determinados os teores de Ca, Mg, K, P, N (NT) e de matéria orgânica do solo (MOS) e com isso, calculada a taxa de enriquecimento de enxurrada. O manejo exerce maior influência nas perdas de solo do que nas perdas de água. Menores perdas foram encontradas no reflorestamento implantado em 2013 (solo), pasto bem manejado (água) e reflorestamentos (nutrientes e matéria orgânica). Há uma tendência de estabilização dessas perdas com o tempo de implantação dos sistemas. A tendência geral das perdas de nutrientesno PVA foi NT > Ca > Mg > K > P; e no Argisol foi de NT > Ca > K > Mg > P. As taxas de perdasde MOS e NT seguem a ordem: solo descoberto > rotação cultural > pasto degradado > pasto bemmanejado > reflorestamento, no PVA; e solo descoberto > mata nativa > reflorestamento, no Argisol. Oreflorestamento e o manejo das pastagens são estratégias conservacionistas que minimizam as perdaspor erosão hídrica na sub-bacia das Posses, Extrema-MG. O manejo exerce maior influencia nas perdas de solo e de materiais a ele relacionados do que nas perdas de água. A manutenção da mata nativa sob...

Pedotransfer functions to estimate bulk density from soil properties and environmental covariates: Rio Doce basin

Soil bulk density (b) data are needed for a wide range of environmental studies. However, b is rarely reported in soil surveys. An alternative to obtain b for data-scarce regions, such as the Rio Doce basin in southeastern Brazil, is indirect estimation from less costly covariates using pedotransfer functions (PTF). This study primarily aims to develop region-specific PTFs for b using multiple linear regressions (MLR) and random forests (RF). Secondly, it assessed the accuracy of PTFs for data grouped into soil horizons and soil classes. For that purpose, we compared the performance of PTFs compiled from the literature with those developed here. Two groups of data were evaluated as covariates: 1) readily available soil properties and 2) maps derived from a digital elevation model and MODIS satellite imagery, jointly with lithological and pedological maps. The MLR model was applied step-wise to select significant predictors and its accuracy assessed by means of cross-validation. The PTFs developed using all data estimated b from soil properties by MLR and RF, with R2 of 0.41 and 0.51, respectively. Alternatively, using environmental covariates, RF predicted b with R2 of 0.41. Grouping criteria did not lead to a significant increase in the estimates of b. The accuracy of the regional PTFs developed for this study was greater than that found with the compiled PTFs. The best PTF will be firstly used to assess soil carbon stocks and changes in the Rio Doce basin.(AU)

Pedotransfer functions to estimate bulk density from soil properties and environmental covariates: Rio Doce basin

Soil bulk density (b) data are needed for a wide range of environmental studies. However, b is rarely reported in soil surveys. An alternative to obtain b for data-scarce regions, such as the Rio Doce basin in southeastern Brazil, is indirect estimation from less costly covariates using pedotransfer functions (PTF). This study primarily aims to develop region-specific PTFs for b using multiple linear regressions (MLR) and random forests (RF). Secondly, it assessed the accuracy of PTFs for data grouped into soil horizons and soil classes. For that purpose, we compared the performance of PTFs compiled from the literature with those developed here. Two groups of data were evaluated as covariates: 1) readily available soil properties and 2) maps derived from a digital elevation model and MODIS satellite imagery, jointly with lithological and pedological maps. The MLR model was applied step-wise to select significant predictors and its accuracy assessed by means of cross-validation. The PTFs developed using all data estimated b from soil properties by MLR and RF, with R2 of 0.41 and 0.51, respectively. Alternatively, using environmental covariates, RF predicted b with R2 of 0.41. Grouping criteria did not lead to a significant increase in the estimates of b. The accuracy of the regional PTFs developed for this study was greater than that found with the compiled PTFs. The best PTF will be firstly used to assess soil carbon stocks and changes in the Rio Doce basin.