Effect of tissue phosphorus concentration on the mineralisation of nitrogen from stylo and cowpea residues

Nguluu, S N and Probert, M E and Myers, R J K and Waring, S A (1997) Effect of tissue phosphorus concentration on the mineralisation of nitrogen from stylo and cowpea residues. Plant and Soil, 191 (1). pp. 139-146. ISSN 1573-5036

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Laboratory studies were conducted to investigate the effect of phosphorus concentration in residues of cowpea (t Vigna unguiculata, L. Walp) and stylo (t Stylosanthes hamata, L., cv Verano) on their rate of nitrogen mineralisation when incubated in a soil whose P status was deficient for plant growth. Residues with a range of P concentrations were obtained by applying varying rates of P to soil in which the plants were grown in the field or the glasshouse. Variations in P concentration of field- or glasshouse-grown residues were not accompanied by variations in other chemical components (C:N ratio, lignin and polyphenol concentrations). Both lignin and polyphenol concentrations were higher in the field-grown than in the glasshouse-grown residues. Lignin concentration was greater in cowpea than in stylo, but polyphenols were higher in stylo. Cowpea residues mineralised N less rapidly than stylo. N mineralisation from residues with low P concentration was consistently less than from those of higher P concentration; reduced mineralisation was observed for P concentration in the residues below 1.6 g kg−1. When inorganic P was added to the residue-soil systems, N mineralisation from the residues was increased, though no interaction between the effects of adding inorganic P and P concentration in the residues was observed

Item Type: Article
Uncontrolled Keywords: cowpea; crop residues; mineralisation; nitrogen; phosphorusconcentration; t Stylosanthes
Subjects: Others
Depositing User: Ms K Syamalamba
Date Deposited: 10 Apr 2013 08:47
Last Modified: 10 Apr 2013 08:47
URI: http://oar.icrisat.org/id/eprint/6739
Official URL: http://dx.doi.org/10.1023/A:1004261812861
Acknowledgement: UNSPECIFIED
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