Soil burial influencing response to applied phosphorus in a torrifluvent
2002
Rahmatullah (University of Agriculture, Faisalabad (Pakistan). Dept. of Soil Science) | Salim, M. | Gill, M.A. | Hussain, K. | Aziz, T.
Crops responses are erratic to fertilizer application on buried Shahdrah series in sub-recent alluvial plains of the river Ravi due to three distinct soils stacked one over other. Samples of the three soils were used for laboratory and greenhouse studies to monitor their P supplying behavior. Estimation of physical composition of the soils, their P sorption behavior and the recovery of applied P against NaHCO3 extraction separated surface soil (S1) and the original soil (S3) from the fine dense alluvium (S2) deposited by flood water. The two types of the soils differed widely in their clay content, free lime and active amorphous iron oxides, barley plants did not survive in fine dense alluvium (S2) due to high sodicity and maximum clay (54%) content. Plants also did not respond to P application in S1 due to its high initial NaHCO3, extractable P. Phosphorus sorption described by the Freundlich isotherm in the three soils had steeper slope in S1 and S3 than its flatter shape in S2. However, the curve shifted a little upward in S1 due to its high initial NaHCO3 extractable P. Different rates of P application were calculated for the three soils from the regression equations of NaHCO3 extractable P versus applied P to achieve sufficiency level of 8 mg P kg-1. No application of P was required for the surface soil (S1). It was 17 mg P kg-1 for dense alluvium (S2) and 1 mg P kg-1 for original soil (S3). Further incubation studies involving more soils has been suggested for better understanding the behavior of applied P in relation to soil properties.
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