Soil quality and soybean productivity in crop-livestock integrated system in no-tillage

Abstract: The objective of this work was to evaluate the quality of the soil and its relation with soybean (Glycine max) yield in an integrated crop-livestock system (ICLS), with intercropping between grasses and legumes in the pasture phase. The experiment was carried out in the state of Mato Grosso, Brazil, on a dystrophic Oxisol, in which grasses (Megathyrsus maximus 'BRS Tamani' and Urochloa brizantha 'BRS Piatã'), intercropped with cowpea (Vigna unguiculata 'BRS Tumucumaque') and pigeon pea (Cajanus cajan 'BRS Mandarim'), were cultivated after soybean harvest. A randomized complete block design was used, with three replicates, in a split-plot arrangement, in which grasses were considered as plots, and legumes as subplots. Legume intercrops provided increases of C and total N stocks. The intercrops caused the increase of C and N of the microbial biomass, whereas the single cultures contributed to stress in the soil microbiota. The activity of the urease enzyme was sensitive to management changes in the short term, but acid phosphatase and β-glucosidase were poorly sensitive indicators. Soil quality is high with intercropping between grasses and legumes, with positive effects on soybean grain yield.

摘要：本研究旨在评估种养整合系统（integrated crop-livestock system, ICLS）的土壤质量水平，及其与牧草阶段禾本科与豆科作物间作模式下大豆（Glycine max）产量的关联。试验于巴西马托格罗索州的退化氧化土（dystrophic Oxisol）上开展，在大豆收获后，种植禾本科牧草[大黍（Megathyrsus maximus 'BRS Tamani'）与布氏虎尾草（Urochloa brizantha 'BRS Piatã'）]，并分别与豇豆（Vigna unguiculata 'BRS Tumucumaque'）、木豆（Cajanus cajan 'BRS Mandarim'）进行间作。试验采用随机完全区组设计（randomized complete block design），设置3次重复，采用裂区布局：以禾本科牧草为主区，豆科间作作物为副区。结果显示，豆科间作可提升土壤碳（C）与全氮（N）储量；间作模式可提高土壤微生物量碳、氮含量，而单作处理会加剧土壤微生物群落的胁迫状态。脲酶（urease）活性对短期管理措施变化较为敏感，但酸性磷酸酶（acid phosphatase）与β-葡萄糖苷酶（β-glucosidase）的响应敏感度较低。综上，禾本科与豆科作物间作可维持较高土壤质量，对大豆籽粒产量具有积极影响。