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Changes in P fractions and sorption in an Alfisol following crop residues application
Author(s) -
Reddy Damodar D.,
Rao Subba A.,
Singh Muneshwar
Publication year - 2005
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200421444
Subject(s) - alfisol , chemistry , fertilizer , incubation , fractionation , sorption , crop residue , residue (chemistry) , zoology , soil water , bioavailability , agronomy , environmental chemistry , chromatography , adsorption , biochemistry , agriculture , biology , organic chemistry , ecology , bioinformatics
With the emphasis on sustainable agriculture, attention has been increasingly turning to recycling of crop residues as a component of fertility management strategies for tropical soils. We assessed the effects of soybean residue (SR) and wheat residue (WR) applied either alone or in combination with fertilizer P (FP) on dynamics of labile P, distribution of P fractions, and P sorption in a semiarid tropical Alfisol by conducting a 16 w long incubation experiment. The amount of P added through crop residues, FP or their combinations was kept constant at 10 mg P (kg soil) –1 . Addition of SR or WR resulted in net increase of labile inorganic (P i ) and organic P (P o ) and microbial P throughout the incubation period, except that the WR decreased labile P i during first 2 w due to P i immobilization. The P immobilization associated with WR addition was, however, offset when fertilizer P was combined with WR. Generally, the increases in labile‐P fractions were larger with the SR and SR+FP than with the WR and WR+FP. The sequential fractionation of soil P at the end of 16 w indicated that a major part of added fertilizer P transformed into moderately labile and stable P fractions as evident from the increased NaOH‐P i and HCl‐P in the FP treatment. In contrast, the addition of SR and WR alone or in combination with FP favored a build‐up in NaHCO 3 ‐P i and ‐P o and NaOH‐P o fractions while causing a decrease in NaOH‐P i and HCl‐P fractions. The addition of these crop residues also effectively decreased the P‐sorption capacity and hence reduced the standard P requirement of the soil ( i.e., the amount of P required to maintain optimum solution P concentration of 0.2 mg P l –1 ) by 24%–43%. Results of the study, thus, imply that soybean and wheat crop residues have the potential to improve P fertility of Alfisols by decreasing P‐sorption capacity and by redistributing soil P in favor of labile‐P fractions and promoting accretion of organic P.