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New Mechanistic Phosphorus Fertilizer Recommendation Model Based on Two Intrinsic Phosphorus Pools in Tropical Soils
Author(s) -
Shuai Xiufu
Publication year - 2019
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2018.12.0485
Subject(s) - fertilizer , phosphorus , soil water , desorption , nutrient , crop , adsorption , environmental science , agronomy , chemistry , tropics , sowing , soil science , biology , ecology , organic chemistry
No mechanistic model for phosphorus (P) fertilizer recommendation is available for nutrient management in tropical soils. Soil intrinsic P pools, including a weakly and a tightly adsorbed P pool, were proposed to quantify actual soil available P. The goal of this study was to develop a new mechanistic P fertilizer recommendation model based on the two pools. The public data set of a corn ( Zea mays L.) field experiment was used to estimate the daily corn P uptake. Seven soils were used to demonstrate the effects of P‐sorption site density (PSSD) and desorption rate of the tightly adsorbed P pool on the P fertilizer recommendation. Dynamics of soil P pools in a corn–soil system were modeled based on the transformation between the pools, the daily crop P uptake, and P fertilizer added at the beginning of planting. The weakly adsorbed P pool was required to be positive to represent no constraint of crop P nutrition. Results showed that the derived P recommendation model was a linear model of the total crop P uptake minus the two pools with three different coefficients. The weakly adsorbed P pool was readily available for crop uptake. The coefficients of the total crop P uptake and the tightly adsorbed P pool were >1.0 and <1.0, respectively, and they changed slightly with PSSD but were dependent on the desorption rate. The coefficient of the total crop P uptake showed a maximum 1.679 at the desorption rate 0.0118 d −1 . Core Ideas A P recommendation model was developed based on dynamic soil surface reaction and crop uptake. Intrinsic weakly and tightly adsorbed P pools quantify dynamics of soil P supply. P requirement was a linear function of crop uptake and initial values of P pools. Model parameters were determined by soil P‐sorption site density and desorption rate.