Citric and malic acids at concentrations of 0.1, 1.0, 10, and 100 mmol/L were added to three Ultisolsand one Oxisol. The amount of P in solution increased with increasing organic acid concentrations, while theaniount ...Citric and malic acids at concentrations of 0.1, 1.0, 10, and 100 mmol/L were added to three Ultisolsand one Oxisol. The amount of P in solution increased with increasing organic acid concentrations, while theaniount of Fe- and Al-bound P decreased. This result suggested that naturally occurring products of organicmatter decomposition could increase the P availability to plants in soils where there is a relatively large poolof Fe- and Al-bound P.The interactions between citric and malic acids at the above concentrations. and P added at rates of10, 20, 40, and 80 mg/kg were determined. At zero levels of organic acids, all added P became either labileor bound, and greater proportions remained soluble as the concentration of organic acids increased, whichsuggested that organic acids reduced fixation of dissolved P in Fe- and AI-rich soils.Agricultural practices which increase organic matter input on P-deficient acid soiIs could decrease Pdeficiency. This would be important in many tropical and subtropical regions where these soils are common,and where the costs of fertilizers and lime are relatively high.展开更多
文摘Citric and malic acids at concentrations of 0.1, 1.0, 10, and 100 mmol/L were added to three Ultisolsand one Oxisol. The amount of P in solution increased with increasing organic acid concentrations, while theaniount of Fe- and Al-bound P decreased. This result suggested that naturally occurring products of organicmatter decomposition could increase the P availability to plants in soils where there is a relatively large poolof Fe- and Al-bound P.The interactions between citric and malic acids at the above concentrations. and P added at rates of10, 20, 40, and 80 mg/kg were determined. At zero levels of organic acids, all added P became either labileor bound, and greater proportions remained soluble as the concentration of organic acids increased, whichsuggested that organic acids reduced fixation of dissolved P in Fe- and AI-rich soils.Agricultural practices which increase organic matter input on P-deficient acid soiIs could decrease Pdeficiency. This would be important in many tropical and subtropical regions where these soils are common,and where the costs of fertilizers and lime are relatively high.
