Study the effect of different levels of nitrogen and potassium fertilizers on yield, yield components and growth of rice c. v. Khazar

The effects of 0,30,60,90 and 120 Kg N/ha and 0,100,200 or 300 Kg K2O/ha on growth, grain yield, yield components of transplanted rice cv. Khazar were investigated in a field trial in 2001 crapping system at the Rice Research Institute, Rasht, Iran. Results showed that increasing rates of nitrogen fertilizer, increased plant height, tiller number per square meter and panicle length. Yield response to applied nitrogen fertilizer was significant up to 60 Kg N/ha. Grain yield was not affected by potassium fertilizer. However, the highest yield was obtained from 60 kg N/ha + 300 kg K2O/ha. Total dry matter increased as nitrogen rate increased up to 60 kg N/ha. Potassium fertilizer did not affect the total dry matter production. Nitrogen and potassium effect on the harvest index (HI) was not significant. Increasing the rates of nitrogen from 0 to 120 kg/ha increased the number of rice panicles per square meter. Potassium fertilizer did not have significant effect on panicles/m2. Spikelets per panicle increased by nitrogen and potassium and was greatest at 120 kg N/ha + 300 kg K2O/ha. Percentage of filled grains was affected by nitrogen and potassium fertilizers. Thousand grain weight was not affected by nitrogen and potassium fertilizer. Grain yield correlated positively with panicle number/m2 and spikelet per panicle. Nitrogen fertilizer had significant effect on Leaf Area Index (LAI) but potassium did not affect LAI significantly. Crop Growth Rate (CGR) and Net Assimilation Rate (NAR) were affected by both nitrogen and potassium fertilizers.