Does Crop-Livestock-Forest Systems Contribute to Soil Quality in Brazilian Savannas?

ABSTRACT In this paper we discuss the impact on conversion degraded pasture areas into an integrated crop, livestock and forest system (ICLFS). We collected 30 soil samples at 0-0.1 m depth in five agroforestry systems, degraded pasture and native areas along Brazilian Cerrado biome. We analyzed the influence of chemical variables on microbial biomass carbon and enzyme activity using multivariate statistic analysis. The land use explained only the variation of microbial biomass carbon and seasonality explained the variation in glycine aminopeptidase activity. The sample controls differ from the other soil areas due to their greater biological activity (MBC). The enzymatic indicators showed that the biological activity is lower in degraded pasture. It was observed that the ICLFS system had a positive effect on the microbial activity (MBC and soil enzyme) when compared to pasture. This reinforces the importance of adopting more sustainable practices to improve soil quality.摘要 本研究探讨了将退化牧场改造为作物-畜牧-森林复合系统（integrated crop, livestock and forest system, ICLFS）所产生的生态影响。研究团队于巴西塞拉多生物群落沿线的5种农林业系统、退化牧场及原生区域内，采集了0~0.1米深度的土壤样本共计30份。采用多元统计分析方法，探究了土壤化学变量对微生物生物量碳及土壤酶活性的影响。结果显示，土地利用方式仅能解释微生物生物量碳的变异，而季节周期性则可解释甘氨酸氨肽酶活性的变异。对照土壤样本的生物活性（即微生物生物量碳，MBC）更高，因此与其余土壤区域存在显著差异。酶活性指标结果表明，退化牧场的土壤生物活性更低。研究观察到，相较于传统牧场，作物-畜牧-森林复合系统（ICLFS）对土壤微生物活性（微生物生物量碳与土壤酶活性）具有积极改善作用。该结果进一步印证了采用更可持续的土地管理模式以提升土壤质量的重要性。