Evaluation of the Parameters of Soil Phosphorus Availability Factors in Predicting Yield Response and Phosphorus Uptake

Abstract

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, Ec, E1.0, Q0 value, NH4F‐P, NaOH‐P, H2SO4‐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 0.25M NaOH‐0.1M Na2CO3 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 (0.01M CaCl2 soluble P, aH2PO4i 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.

Phosphorus diffusion in soils in relation to some edaphic factors and its influence on P uptake by maize and wheat

“…Significant negative correlation of capacity factor with soil solution P and % P in the shoot confirms this observation. Dalai & Hallsworth (1976) have made similar observations.…”

“…Phosphorus renewal in the soil solution is thus an essential pathway in the process of nutrient acquisition by plant roots. This ability of the soil to renew the P depleted by plants is related to its capacity factor (Dalai & Hallsworth, 1976). Movement of P to the root absorption site is another important factor that can become limiting in plant uptake (Fried & Shapiro, 1956).…”

Evaluation of chemical extractants for assessing phosphate availability in volcanic ash soils

“…3 Yo = Grain yield without the application of P in the field trial. "Yr = Relative yield in the field trial without added P. 5 Ym = Estimated grain yield (field trial) for recommended rate of P. 6 Bd = Bulk density.…”

“…Some researchers (9,10) have found P uptake to be proportional to quantity and intensity, whereas others (5,6) have shown that a term combining the factors of intensity, quantity and buffer capacity was a better measure of soil P status than was either quantity or intensity alone. Furthermore, the relationship between the intensity and quantity of labile P is governed by the buffer capacity in such a way that, at any particular level of labile P, the higher the buffer capacity, the lower the concentration of P in solution (1,10).…”

Increase in phosphorus availability of upland Andosol under different fertilization conditions measured by isotopic techniques

“…It was reported that the L-val ue measured by the isotopic dilution method and E -val ue measured by the isotopic exchange kinetic method were more suitable for estimating the amount of available soil P (Russel et al 1957;Dalal and Hallsworth 1976;Tran et al 1988;Kato et al 1995a, b), and that isotope techniques could become valuable tools for understanding the P dynamics in soil-plant systems (Di et al 1997).…”