Diverse production systems affect soil phosphorus forms and crop productivity in tropical soil

Diversified agricultural systems, associated with greater species diversity (SD), can alter the dynamics of phosphorus (P) in the soil and consequently increase crop productivity. This study evaluated the P forms and yields of soybean and cotton in a sandy loam Ultisol under various levels of species diversity of land use in tropical soil. The experimental design was randomized blocks, with five levels of SD: very low (VL), low (LW), medium (AVG), long-term mean (AVL) and high (ICLS). The increase in the level of species diversity significantly (255 %) influenced the yield of cotton in the ICLS compared with that in the LV and that of soybean in the 2022/23 crop. Treatments with greater species diversity significantly increased P concentrations in the most labile soil fractions. The Melhlich-3 P fraction represented approximately 30 %, and the organic P represented approximately 9 % of the total P in the three evaluated layers, whereas the occluded P fraction represented more than 40 % of the total P in the soil. In the 10–20 cm layer, the ICLS recorded the highest proportion of labile P. Additionally, the determination of available P should be performed in the more superficial layers (0–5 and/or 5–10 cm), especially in the no-tillage system, due to the greater accumulation of P in the upper layers. ICLS increased the availability of P in the subsurface by increasing the amount of labile and moderately labile P forms. • High diversity increased labile and organic phosphorus in sandy loam soils. • High diversity enhanced subsurface P availability and reduced occluded P fractions. • Cotton yield rose 255 % under high compared to low diversity systems. • Available P in 10–20 cm soil layer is strongly correlated with cotton yield. • New P fractionation method linked soil P forms to crop productivity.