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Soil Test Phosphorus and Phosphorus Fractions with Long‐Term Phosphorus Addition and Depletion
Author(s) -
Zhang T. Q.,
MacKenzie A. F.,
Liang B. C.,
Drury C. F.
Publication year - 2004
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/sssaj2004.5190
Subject(s) - fertilizer , gleysol , phosphorus , chemistry , zoology , agronomy , human fertilization , soil test , soil water , environmental science , biology , soil science , organic chemistry
The fate of fertilizer P in soil during crop production has to be determined to evaluate the long‐term economic value and sustainability of fertilizer practices. We assessed changes in soil test P and soil P fractions with continuous P fertilization and soil P depletion under continuous corn ( Zea mays L.) in a Ste. Rosalie clay soil (humic Gleysol; fine, mixed, frigid, Typic Humaquept). Soil samples were analyzed for Mehlich‐3 P (M‐3 P) and P fractions using a modified Hedley's procedure. Soil M‐3 P values remained constant in spite of crop removal in soil not receiving fertilizer for 10 yr. Continuous P fertilization at rates from 44 to 132 P ha −1 yr −1 increased linearly soil M‐3 P, with 6.3 kg P ha −1 of net P addition required to increase M‐3 P by 1 mg P kg −1 Residual fertilizer P in soil resulted from the continuous P addition were found predominately in labile inorganic P (LP i ) (NaHCO 3 –P i ) and moderately labile P i (MLP i ) (NaOH‐P i ). Increased P rates favored soil P transformation from LP i to MLP i , indicating enhanced soil P retention. With P depletion, soil M‐3 P declined in plots previously receiving 132 kg P ha −1 yr −1 , with 4.2 kg P ha −1 crop P removal decreasing soil M‐3 P by 1 mg P kg −1 Continuous crop removal of soil residual P (Res‐P) resulted in decreases in soil LP i and increases in MLP i , an indication of increased retention of Res‐P with time. However, moderately stable P i (HCl‐P i ) remained constant, both with continuous P addition and P depletion. Conversion of residual fertilizer P to less available P forms in soil was a slow process and thus the fate of the Res‐P should be taken into consideration when developing soil nutrient management plans.