Effects of Combined Application of Nitrogen and Phosphorus on their and Potassium Uptake by Rice Plant under Flooded vs. Non-flooded Conditions

Rice (Oryza sativa L.) is one of the strategic crops in Iran and water shortage is the most important abiotic stresses limiting its yield. In this research the effect of variety، water regime، nitrogen (N) and phosphorus (P) levels on N، P and K uptake was studied under greenhouse conditions. The experiment design was factorial based on randomized complete blocks with three replications. The factors included two varieties of rice (Hashemi and Ali Kazemi)، two water regimes (flooded and periodic saturation)، three nitrogen levels as urea (0، 75، 150 mg kg-1) and three P levels as mono calcium phosphate (0، 25، 50 mg kg-1). After 90 day growth period، plants were harvested and total content and concentration of N، P and K in shoot and root were determined. The results showed that K concentrations in shoot and root، K content in shoot and N translocation factor in Ali Kazemi were greater than Hashemi variety. But P concentration in root، P translocation factor and P content of the root in Hashemi became higher in Ali Kazemi variety. P concentration of shoot and root، K concentration of shoot، N content of shoot، P and K contents of the shoot and root under flooded conditions were significantly (P<0. 01) higher under periodic saturation conditions. Interaction between N and P produced significant effect on N and K concentrations of shoot and root، P concentration of root، N and P translocation factors، N، P and K contents of the shoot and root.