Adsorption and desorption of phosphate in some semi-arid tropical Indian Vertisols

Shailaja, S.; Sahrawat, K. L.

doi:10.1007/bf01063335

Cited by 15 publications

(7 citation statements)

References 16 publications

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“…This agrees with the results of electroultrafiltration (EUF) extractions on some Indian Vertisols [19]. The additional P desorbed in the last of the CAER extractions was small in most samples and it had been thought that Resin-a might predict available P better than Resin8-P because it may be viewed as the maximum amount of CAER extractable P. A similar asymptotic estimate of resin extractable P was the best chemical assessment of available P in about 500 tropical soils [16], although most soils were acid.…”

Section: Sequential Extraction With Resinsupporting

confidence: 90%

Assessment of fertilizer P residues in a calcareous vertisol

Warren

Sahrawat

1993

Fertilizer Research

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The amounts of available P in a Typic Pellustert containing different levels of residual fertilizer P were assessed in a field experiment and chemically with cation-anion-exchange resin, using: (i) P desorbed after 1 extraction, (ii) cumulative P from 8 extractions [Resin8-P] and (iii) the asymptote of the extraction curve. P exchangeable to 32p, Olsen-P and P extracted by dilute salt solution (0.03 M KC1) were also measured. P available to sorghum in 1989 was strongly influenced by fertilizer P applied in 1988, but not by P applied in 1987. Olsen-P and Resin8-P both reflected well the effects of residual P on yield and P uptake and could therefore be used to predict available residual P. The amounts of Resin8-P were much larger than Olsen-P, so it was easier to observe the differences between soil treatments, but Olsen-P gave the better correlations with grain yield and P uptake.Multiple regressions of crop yield or P uptake with amounts of P applied in 1987 and 1988 gave the best correlations, without the need for practical work. Thus, the development of an appropriate model based on records of P fertilization is seen as the most effective way to predict availability of residual P. Assessments related to the P intensity and desorption rate using resin were not able to improve predictions of available P, indicating that within one soil the quantity of residual P is most important, but for comparisons between soils, account will need to be taken of differences in soil characteristics.

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