Abstract The development of agroecosystems that can provide multiple ecosystem services with a reduced need of external inputs, requires management practices that foster ecological processes to enhance soil quality and crop productivity. We assessed the direct and indirect impacts of farmers’ management practices on plant diversity, soil quality and crop productivity in coffee and pasture fields belonging to different types of farms: agroecological, conventional, and large-scale. The study was carried out in twelve farms in the Zona da Mata, Brazil. For each of the total of 24 fields (twelve pastures and twelve coffee) we recorded 41 variables associated with management practices, indicators of plant diversity (taxonomical, structural and functional diversity) and soil quality (biological, chemical and physical properties). The direct and indirect effects of management on plant diversity, soil quality and in the case of coffee, crop productivity, were assessed using structural equation models. In the case of pastures, we found that increased plant diversity due to agroecological management resulted in higher soil quality, probably due to higher soil litter cover and plant structural heterogeneity. Yet, practices presented in the agroecological farms also had a direct negative effect on soil quality, which indicates that increased plant diversity in pastures needs to be combined with other agroecological management practices than currently adopted. In the case of coffee, we show that despite the higher weeding intensity and higher use of external inputs in large-scale and conventional coffee farming systems, these practices did not result in increased soil quality or coffee productivity as compared to agroecological systems. In contrast, agroecological coffee management was associated with increased plant diversity, which, in turn, was positively associated with soil microbial biomass carbon. Our results highlight a causal pathway of agroecological management leading to increased plant diversity and, in turn, maintenance or increase in soil quality. While no causal link between agroecological coffee management and coffee productivity could be demonstrated, the biodiversity-mediated pathway resulted in similar coffee productivity in agroecological farms as compared to conventionally managed farms, which relied on pesticides and higher inputs of chemical fertilizers. We conclude that agroecological practices can be efficient to maintain satisfactory crop yields and soil fertility without the need of intensive use of external inputs and weeding.

中文翻译：

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农业生态管理对巴西大西洋森林牧场和咖啡系统中植物多样性和土壤生态系统服务的影响

摘要 农业生态系统的发展可以在减少外部投入需求的情况下提供多种生态系统服务，需要管理实践来促进生态过程，以提高土壤质量和作物生产力。我们评估了农民的管理实践对属于不同类型农场的咖啡和牧场的植物多样性、土壤质量和作物生产力的直接和间接影响：农业生态、常规和大规模。该研究在巴西的 Zona da Mata 的 12 个农场中进行。对于总共 24 个田地（12 个牧场和 12 个咖啡）中的每一个，我们记录了 41 个与管理实践、植物多样性指标（分类、结构和功能多样性）和土壤质量（生物、化学和物理特性）相关的变量。使用结构方程模型评估了管理对植物多样性、土壤质量以及咖啡作物生产力的直接和间接影响。在牧场的情况下，我们发现由于农业生态管理增加的植物多样性导致更高的土壤质量，这可能是由于更高的土壤凋落物覆盖和植物结构异质性。然而，生态农业农场的做法也对土壤质量产生了直接的负面影响，这表明牧场植物多样性的增加需要与目前采用的其他农业生态管理做法相结合。就咖啡而言，我们表明，尽管在大规模和传统的咖啡种植系统中除草强度更高且外部投入的使用更多，与农业生态系统相比，这些做法并未提高土壤质量或咖啡产量。相比之下，农业生态咖啡管理与植物多样性增加有关，而植物多样性又与土壤微生物生物量碳呈正相关。我们的结果突出了农业生态管理的因果途径，导致植物多样性增加，进而维持或提高土壤质量。虽然无法证明农业生态咖啡管理与咖啡生产力之间存在因果关系，但与依赖杀虫剂和更多化肥投入的传统管理农场相比，生物多样性介导的途径导致农业生态农场的咖啡生产力相似。