Structure of AMF Community in an Agroforestry System of Coffee and Macauba Palm

Abstract Coffee crop in Brazil is typically grown as a monoculture. However, we hypothesized that agroforestry system is favorable association for arbuscular mycorrhizal fungi (AMF), affecting its community structure and potentially impacting crop productivity and agroecosystem health. This study evaluated how the microclimate, soil depth, macauba field spacing and distance between coffee plants and palms affect the structure of the AMF community. The structure of the AMF community was influenced by the soil depth, microclimate features, soil moisture, maximum air temperature, and photosynthetically active radiation (PAR). The distance at which coffee-macauba influences ecological diversity indices of AMF, and higher diversity are related to the proximity between plants. AMF diversity (Richness and Shannon) in the agroforestry system exceeded that observed in the full-sun coffee in the 0-20 soil depth layer. Our results showed that the microclimate, soil depth, plant density, and distance between coffee from macauba affected the AMF community structure.

摘要 巴西咖啡作物通常采用单一栽培模式进行种植。本研究假设，农林业系统对于丛枝菌根真菌（arbuscular mycorrhizal fungi, AMF）而言是更为适宜的共生体系，可对其群落结构产生影响，并潜在地作用于作物生产力与农业生态系统健康。本研究探究了微气候、土壤深度、马考巴棕榈种植间距以及咖啡植株与棕榈间的距离，如何影响丛枝菌根真菌的群落结构。研究发现，丛枝菌根真菌群落结构受到土壤深度、微气候特征、土壤湿度、最高气温以及光合有效辐射（photosynthetically active radiation, PAR）的影响。咖啡与马考巴棕榈之间的距离会影响丛枝菌根真菌的生态多样性指数，且更高的多样性与植株间距离更近呈显著相关。在0-20土层中，农林业系统内的丛枝菌根真菌多样性（丰富度与香农指数）显著高于全日照咖啡栽培模式。本研究结果表明，微气候、土壤深度、植株密度以及咖啡与马考巴棕榈间的距离，均会对丛枝菌根真菌群落结构产生影响。