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Evaluation of the Parameters of Soil Phosphorus Availability Factors in Predicting Yield Response and Phosphorus Uptake
Author(s) -
Dalal R. C.,
Hallsworth E. G.
Publication year - 1976
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/sssaj1976.03615995004000040026x
Subject(s) - phosphorus , soil water , chemistry , phosphate , zoology , sowing , carbonate , agronomy , soil science , geology , biochemistry , biology , organic chemistry
The importance of quantity, intensity, capacity, and rate factors of soil P availability to account quantitatively for the variation in P uptake and wheat grain yield in pot and field experiments was studied. Among the parameters of the quanitity factor ( L, E, E c , E 1.0 , Q 0 value, NH 4 F‐P, NaOH‐P, H 2 SO 4 ‐P, organic P, Olsen P, Colwell P, carbonate P, and anion‐exchange resin, AER‐P), L value was found to be highly correlated with P uptake at 35 and 150 days after planting (maturity) when all the soils were considered. However, the carbonate P (soil P extracted for 16 hours with 0.25 M NaOH‐0.1 M Na 2 CO 3 at a soil/solution ratio of 1:100) was found to be the best parameter of the quantity factor when the soils containing high amounts of hematite/goethite (> 20%) were excluded. The parameters of the intensity factor (0.01 M CaCl 2 soluble P, a H 2 PO 4 i and phosphate potential) were significantly correlated with P uptake at early growth (35 days) whereas the parameter of the capacity factor (maximum buffering capacity, Mb ) was bezter correlated with P uptake at the later stage (150 days). The rate factor, as measured by AER was better correlated with P uptake at 35 days than with P uptake at 150 days after planting. The quantity factor as measured by the carbonate P accounted for 75 and 93% of the variation in P uptake and grain yield, respectively. The capacity factor, Mb when combined with the quantity factor accounted for more of the variation in P uptake (150 days) from 75 to 86%. The intensity and the rate factors had a smaller effect.