17 O. U. Rehman S. M. Mehdi M. Sarfraz M. A. Shakir G. Shabir Soil Journal of Animal and Plant Sciences JAPS 20132013/04/01 23 2 480-486 1018-7081 NA <p>Phosphorus (P) nutrition of the rice cropping system is very important due to alternate wetting and drying cycles. A field experiment was conducted on a sandy loam soil (Typic Camborthid) to observe residual effect of P on succeeding crops and rate of P depletion after one crop rotation (wheat- sorghum fodder-rice). Rice was raised as second crop on the residual P after sorghum fodder, grown after wheat. Analysis of variance (ANOVA) technique under RCBD was used and Duncan&rsquo;s multiple range test (DMR) was applied to see the significance of difference among treatment means. Maximum residual P after sorghum fodder was 13.10 mg kg-1 , considered quite sufficient for rice crop. The significantly higher yield of paddy (2.83 Mg ha-1) and straw (2.96 Mg ha-1) was found where residual P was 10.65 mg kg-1 soil. Maximum P concentration (0.15 %) in paddy was found at highest residual P level while in straw it was maximum (0.10 %) where residual P was 10.65 mg kg-1 soil. Similar trend was found in case of P uptake i.e. it was significantly higher in paddy (4.22 Kg ha-1) at highest residual P level and straw (3.05 Kg ha-1) where residual P was 10.65 mg kg-1 while total P uptake was maximum (7.20 kg ha-1) at highest residual P level. Maximum Olsen- P (8.70 mg kg-1) was found after harvest of rice crop where maximum P was applied to wheat. Level of P depletion at the end of three crops was found to be 0.004 mg kg-1 annum-1 where P was applied at 13.76 mg kg-1 soil and this depletion was promoted where no NPK was applied and further deterioration was noticed where only NK was applied without P. However at the higher rates of P application, there was no net P depletion It may be concluded from this study that phosphatic fertilizers be recommended and applied to the crops by taking P adsorption capacities into the account and P application should be soil and crop specific as the solution P and Olsen P vary with varying soils and crops. The residual P upto 13.1 mg Kg-1 can support 2 to 3 succeeding crops in loose textured soils and soils are being mined annum-1 @ 0.138 mg P kg-1 if no fertilizers are applied @ 0.149 mg P kg-1 if only NK are applied in light textured soils under rice cropping system.</p> P decline rate, phosphorus, residual effect, rice, Typic Camborthid Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2013-JAPS-225