Arbuscular Mycorrhizal Association is Induced by Long-Term Cotton Cropping and Enhances P Uptake and Initial Growth of Cotton Plants by Legacy P Exploration in Soil

Production systems can affect soil properties, such as soil fertility and microbiological community and activity, favoring plant growth and crop yield. This study aimed to investigate the effect of successive cropping systems on the chemical, biochemical, and biological properties of a tropical Oxisol and their relationship with cotton initial growth and nutritional status. soil samples were collected in areas with different soybean/maize/cotton cropping system histories (T0—consolidated soybean/corn system; T1—first year of soybean/cotton system; T2—second year of soybean/cotton system; T3—third year of the soybean/cotton system, and T4—fourth year of the soybean/cotton system; T10—tenth year of soybean/cotton system). First, we evaluated the effect of T0—T4 on soil properties and cotton initial growth (cropping history experiment). Then, we evaluated the effect of dilution and autoclaving in T10 samples on soil properties and cotton growth (soil dilution/autoclaving experiment). Both experiments were carried out under greenhouse conditions. in the cropping history experiment, we observed that longer soybean/cotton systems increased P availability and legacy P index in soil and favored arbuscular mycorrhizal colonization in cotton roots and P uptake by cotton plants. Similarly, we observed in the soil dilution/autoclaving experiment that the sterilization limited the mycorrhizal colonization and induced P deficiency, even with available P above the critical limit in soil. the results indicated that the successive soybean/cotton cropping for several years (long-term) stimulates root mycorrhizal colonization of cotton and increases legacy P in soil compared to the recent soybean/cotton cropping, improving legacy P exploration, P uptake, and the growth and development of cotton plants.