Effect of Calcium on Nitrogen Utilization by Rice in Saline Soils

Calcium Effect on Nitrogen Utilization by Rice

Abstract

In the study of the effect of CaSO4 application and soaking of rice seedlings in 2% CaSO4 on N use effi- ciency of rice (var. Shaheen) in 3 sample soils (ECe=0.4, 4.8 and 8.7 dS/m, SAR=1.05, 14.86 and 21.43, pH=7.7, 8.3 and 9.20, respectively), a considerable reduction was observed in tillering (about 26% and 46%), plant height (about 20% and 46%) and yield (about 33% and 53%) of paddy grown in the saline soil (ECe=4.8 and 8.7 dS/m, respectively), as compared to the non-saline soil (ECe=0.4 dS/m), while soaking of seedlings in CaSO4 and N application with or without CaSO nutrition, significantly improved plant growth and paddy yield in all types of soil; overall, 26% increase in plant growth and 48% gain in paddy yield over the control was observed due to N and CaSO application, respec- tively, with soaking of seedlings in high salinity soil. Interestingly, seedlings soaked in 2% CaSO and with N applica- tion but with or without Ca supplementation performed statistically equal. Tissue Na+ significantly decreased, while K+ and Ca+2 concentrations were high due to N application along with Ca nutrition and soaking of seedlings in all types of soil. Maximum N uptake and apparent N recovery were detected in treatments, where N was applied supplemented with CaSO .