ABSTRACT Agricultural management significantly influences soil physical properties and soil erosion. However, there are few studies investigating the long-term effects of agricultural management on soil erosion and physical properties. Here, we assessed the impacts of 20-year agricultural land uses under different management practices on soil physical properties and interrill erosion. This study was conducted on an experimental farm of the Embrapa Western Agriculture, Brazil, and the treatments consisted of soybean cropping under conventional tillage (CT) and no-tillage (NT), crop-livestock integration during the cropping phase (CL-C) and the livestock phase (CL-L), and Brachiaria decumbens pasture under rotational grazing (PP). Soil samples were taken to evaluate the soil physical properties, and 25 rainfall simulations with an intensity of 60 mm h-1 were carried out by using a portable rainfall simulator with runoff plots of 0.7 m2 to quantify surface runoff and interrill erosion. After two decades, the crop-livestock systems (CL-L and CL-C) presented better soil physical properties in the topsoil layer (0.00–0.05 m) with a higher level of aggregation. Soil and water losses ranged from 4.7 to 14.4 × 10-3 kg m-2 and 4.9 to 12.4 mm, respectively. A higher reduction in soil erosion was observed in NT, while CT showed the highest soil erosion rates. These findings indicate an opportunity for a reduction of soil erosion by 60 % by adopting crop-livestock integration comparing CL-C with CT, while livestock under an integrated system (CL-L) decreased water loss by 30 % compared with PP. This study is a starting point for future research, and the findings reveal the potential to minimize the agriculture footprint.

O objetivo deste trabalho foi avaliar a degradação dos inseticidas bifentrina, permetrina e tiametoxam em um solo sob sistemas de integração lavoura-pecuária (SILP), plantio direto (SPD) e convencional (SC), e sua relação com atributos microbiológicos (carbono da biomassa microbiana, respiração basal e atividade das enzimas -glucosidase e fosfatase ácida). O experimento foi realizado utilizando solos incubados (0-10cm) com umidade a 75% da capacidade de campo e 28ºC por 51 dias. Além de aumentos de matéria orgânica, biomassa e atividade microbiana, o sistema SILP também favoreceu a degradação mais rápida dos três inseticidas no solo, em comparação aos outros sistemas avaliados. Dentre os inseticidas avaliados, o tiametoxam apresentou degradação lenta no solo, com valores de meia-vida (TD50) entre 46 e 89 dias. Os valores de TD50 para bifentrina ficaram entre 14 e 44 dias e para permetrina entre 9 e 47 dias, considerando todos os sistemas avaliados.

The aim of this research was to evaluate the degradation of bifenthrin, permethrin and thiamethoxam insecticides in a soil under crop-livestock integration (CLIS), no-tillage (NTS) and conventional (CS) systems and its relationship with microbiological attributes (microbial biomass C, basal soil respiration and activities of β-glucosidase and acid phosphatase). The experiment was carried out using incubated soil (0-10cm) with moisture content about 75% of field capacity at 28ºC for 51 days. Besides the increase in soil organic matter content, biomass and microbial activity, CLIS system also favored a faster degradation of the three insecticides in soil compared to the others. Among the evaluated insecticides, thiamethoxam showed the slowest degradation in soil with half-life (DT50) values between 46 and 89 days. Bifenthrin DT50 values were between 14 and 44 days and for permethrin between 9 and 47 days

O objetivo deste trabalho foi avaliar a capacidade de sistemas de manejo do solo alterarem os teores e a dinâmica do carbono no solo. Foram avaliados a vegetação natural e sistemas de manejo compostos de pastagens, lavouras anuais em preparo convencional e em plantio direto, e rotação de pastagem com lavoura, em experimentos de longa duração conduzidos em Dourados, Maracaju e Campo Grande, MS. Os experimentos foram dispostos em delineamento inteiramente casualizado, em Dourados e Maracaju, e em blocos ao acaso em Campo Grande. Foram determinados os teores e os estoques de C total no solo e em frações granulométricas da matéria orgânica do solo (MOS). A qualidade da MOS foi estimada pela relação entre o C nas frações lábil e não lábil, e expressa na forma de labilidade. A pastagem, permanente ou em rotação com lavouras, aumentou o C na fração particulada e a labilidade da MOS. As menores taxas de acúmulo e os menores estoques de C no solo foram observados nos sistemas apenas com lavouras anuais, enquanto os maiores valores foram registrados nos sistemas com pastagens.

The objective of this work was to evaluate the ability of soil management systems to change the contents and dynamics of soil carbon. Natural vegetation and systems composed of perennial tropical pastures, annual crops under conventional tillage and no-tillage systems, and pasture rotation with annual crops were evaluated in long-term experiments carried out in Dourados, Maracaju and Campo Grande, Mato Grosso do Sul state, Brazil. The experiments were set in a completely randomized block design, in Dourados and Maracaju, and in a randomized complete block design in Campo Grande. Contents and stocks of total C in soil and in soil organic matter (SOM) fractions were measured. The quality of SOM was estimated by the ratio of C in labile and nonlabile fractions, and expressed in the form of lability. Permanent pasture or pasture in rotation with crops increased C in the particulate fraction and the SOM lability. Lower rates of accumulation and of stocks of soil C were observed in systems explored only with annual crops, while higher values were recorded in systems with pasture.

O objetivo deste trabalho foi avaliar mudanças nos atributos químicos, no estoque de carbono e no índice de manejo de C de um Latossolo Vermelho argiloso, sob diferentes sistemas de manejo. Avaliou-se o solo sob sistemas de manejo com diferentes históricos de uso, sob as seguintes coberturas: Zea mays, Urochloa decumbens e Panicum maximum cv. Tanzania. Como testemunha, avaliou-se área sob vegetação de cerrado. Foram coletadas amostras compostas das camadas de solo de 0-5, 5-10 e 10-20 cm. Os teores de fósforo diminuíram com a profundidade, e os maiores valores foram observados na área com P. maximum. Na área com milho, observaram-se maiores valores de K+, Ca++, Mg++, CTC, e de soma e saturação por bases. O teor de C orgânico total do solo (COT) foi maior sob cerrado e menor sob cobertura com P. maximum, à profundidade de 5-10 cm. Os maiores estoques de COT, carbono nas frações particuladas (C-MOP) e nas frações associadas à fase mineral do solo ocorreram na área com U. decumbens, o que promoveu maiores índices de labilidade e de manejo de C, similares aos da vegetação de cerrado. Em todas as coberturas, a labilidade da matéria orgânica do solo diminuiu com o aumento da profundidade. A fração C-MOP apresenta maior sensibilidade às alterações de manejo e relaciona-se ao COT.

The objective of this work was to evaluate changes in the soil chemical attributes, carbon stock and in the C management index of a clayed Oxisol under different management systems. The soil under management systems with different historical usage was evaluated under the following covers: Zea mays, Urochloa decumbens, Panicum maximum cv. Tanzania. A cerrado area was used as check. Four composite samples were collected at 0-5, 5-10 and 10-20 cm soil depths. The phosphorus contents decreased with depth, and the higher values were observed in the area with P. maximum. In the area with Z. mays, higher values for K+, Ca++, Mg++, CEC, and base sum and saturation were observed. The total organic C content (TOC) was higher under cerrado vegetation cover, and smaller under P. maximum at 5-10 cm soil depth. The higher stocks of TOC, and of carbon in particulate fractions (C-POM) and in fractions associate to the soil mineral phase occurred in the area with U. decumbens, which promoted higher values for lability and C management indexes, similar to those for cerrado vegetation. In all coverings, the organic soil matter lability decreased with depth. The C-POM fraction had higher sensibility to variation in management practices, and is related to TOC.

Sistemas de manejo do solo, incluindo lavouras em plantio direto, lavouras (soja) em rotação com pastagens em plantio direto e pastagens permanentes (Brachiaria sp.), foram avaliados quanto à agregação do solo e estabilidade dos agregados. Em três experimentos de longa duração (9 e 11 anos) localizados em Mato Grosso do Sul, o solo foi amostrado nas camadas de 0 a 5, 5 a 10 e 10 a 20 cm, para determinação da estabilidade dos agregados em água e a seco. Foram calculados o diâmetro médio ponderado (DMP) e o índice de estabilidade dos agregados (IEA). Em todos os experimentos, nos sistemas com pastagens, seja de forma isolada ou em rotação com lavouras, foi verificado maior volume do solo, constituindo agregados com tamanho superior a 4,76 mm. Os sistemas com pastagens também apresentaram maior DMP e maior IEA em todos os experimentos. O sistema apenas com lavouras apresentou, nos três experimentos, o maior volume de solo com agregados de tamanho entre 0,25 e 2,00 mm. Esses efeitos ocorreram de forma semelhante em todas as profundidades avaliadas. Entre os locais, observou-se o efeito do teor de argila na agregação, sendo maior em Maracaju e menor em Campo Grande. Foi observada estreita relação entre a estabilidade dos agregados e o teor de C no solo. A formação de macroagregados parece estar relacionada à presença de raízes, que são mais abundantes sob pastagem de gramíneas.

Soil management systems, with crops under no-tillage (NT), crops (soybean) in rotation with pastures under NT and permanent pastures (Brachiaria sp.), were evaluated for soil aggregation and aggregate stability. Three long-term experiments (9 and 11 years) in the state of Mato Grosso do Sul were sampled in the layers 0-5, 5-10 and 10-20 cm for determination of the aggregate stability in wet and dry sieving. The mean weight diameter (MWD) and the aggregate stability index (IAS) were calculated. In all experiments, the greatest soil volume was verified in the systems with isolated pastures or in rotation with crops, constituting aggregates of over 4.76 mm. The soil volume was largest in the crop system, in the three experiments, with aggregate sizes between 0.25 and 2.00 mm. These effects ocurred similarly at all studied depths. In the pasture systems, the MWD was largest and IAS highest in all experiments. The clay effect in the aggregation was greatest in Maracaju and lowest in Campo Grande. A close relation between the IAS and soil carbon was observed. The formation of macro-aggregates seems to be related to the presence of roots, which are more abundant under grass pastures.