The residual value of rock phosphate and superphosphate from field sites assessed by glasshouse bioassay using three plant species with different external P requirements

Abstract

A pot experiment with two lateritic soils measured the relative residual effectiveness (RRE) of superphosphate and three rock phosphate (RP) fertilizers applied six years previously in the field. Three plant species (lettuce, wheat and maize) having very different external P requirements were grown as indicators of P availability. Superphosphate had the maximum RRE (1.0) and low reactive Queensland RP had the minimum RRE (0.04–0.45) for all plant species. For one soil the RRE of reactive North Carolina RP was similar to that of superphosphate (0.87–1.04), but ranged from 0.07 to 0.30 for the other soil. The RRE of Calciphos (one soil only) ranged from 0.60 to 0.98 for all plant species. The RRE of rock phosphate decreased for the three crops in sequence maize> wheat> lettuce for a 30 days growth period. This ranking follows the increasing external P requirement of the three plant species. Very high rates of application of RP may have induced micronutrient deficiencies.

DOI: 10.1007/BF01048782

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Cite this paper

@article{Kumar2005TheRV, title={The residual value of rock phosphate and superphosphate from field sites assessed by glasshouse bioassay using three plant species with different external P requirements}, author={Vijay P. Kumar and Robert J. Gilkes and M. D. A. Bolland}, journal={Fertilizer research}, year={2005}, volume={32}, pages={195-207} }