Spatial variability and microbiological and structural quality in sandy soil under managed functional diversity in integrated crop-livestock systems

Managed functional diversity (MFD), with or without grazing, plays a fundamental role in conservation agriculture. However, its effects on the spatial variability of soil physical and biological quality and crop productivity remain unclear. Therefore, understanding these relationships is essential to inform more efficient and sustainable management strategies, especially in sandy soils. The objective was to investigate the impact of five MFD levels, acting as determinants of soil quality in a context of spatial variability, on soybean (Glycine max) and cotton (Gossypium hirsutum) production in sandy soils of the Cerrado, in Mato Grosso, Brazil. A total of 60 soil samples (0–20 cm), georeferenced, in a grid covering the whole field area, were recorded at MFD levels: very low (VL), low (LW), average (AVG), long-term average (AVL) and high (ICLS). The soil properties and crop yield were assessed in 2017 and 2020, respectively, and results were analyzed using classic statistics and geostatistics by constructing semivariograms and 2D mapping by kriging estimation. The MFD affected microbiological indicators and weighted mean diameter of soil aggregates (MWD), without significant changes in total organic carbon (TOC) of soil. The rise in microbiological stress suggests that a very low MFD is an inefficient and unsustainable agronomic model for crop production. High MFD in ICLS increased soybean productivity by 20 % and cotton productivity by 60 %, which was directly related to improvements in microbiological abundance (C and N of microbial biomass: R² > 0.50) and the soil MWD (R² > 0.60). The MFD induced strong spatial variability for microbial biomass C and N, microbial quotient and MWD and moderate for crop yield. With the shortest effective ranges (a), soybean yield (a = 40 m) and SBR (a = 61 m) were more sensitive to MFD disturbances, exhibiting greater spatial variability at shorter distances. High MFD proved to be an efficient and valid strategy to intensify crop production and increase the microbiological and physical quality of sandy soil in the Brazilian Cerrado.