Effects of drying-rewetting cycles on colloidal phosphorus composition in paddy and vegetable soils.

The impact of drying-rewetting (DRW) cycles on soil phosphorus (P) behavior is well-established; however, its impact on the different-sized colloidal P (CP) in agricultural soils is still unclear. To investigate the effect of DRW events on the mobilization of CP in agricultural soils, and to understand how this impact varies with different DRW cycles and drought intensities, the study explored the role of soil type, CP fractions, and compositions. The concentration of CP was measured in paddy soil and vegetable soil after 3, 6, and 9 DRW cycles of varying intensities.

Phytate exudation by the roots of Pteris vittata can dissolve colloidal FePO.

Phosphorus (P) is limiting nutrient in many soils, and P availability may often depend on iron (Fe) speciation. Colloidal iron phosphate (FePO) is potentially present in soils, and we tested the hypothesis that phytate exudation by Pteris vittata might dissolve FePO by growing the plant in nutrient solution to which FePO was added. The omission of P and Fe increased phytate exudation by P.