Effect of Different Rates of (N,P,K) Fertilizer Rates on Yield and Yield Components of Sinthukha Rice Variety in Two Different Locations

Field experiments were conducted in two different locations: Department of Agricultural Research (DAR) farms in Yezin and Myaungmya Township from July to November 2016. The study was aimed to find out the effect of different rates of Nitrogen (N), Phosphorus (P) and Potassium (K) application on yield and yield components of Sinthukha rice variety. Eight treatments of NPK fertilizer rates: [T1 (max NPK) = 150: 26: 83 kg NPK ha-1, T2 (PK-N) = 0: 26: 83 kg NPK ha-1, T3 (NK-P) = 150: 0: 83 kg NPK ha-1, T4 (NP-K) = 150: 26: 0 kg NPK ha-1, T5 (Low NPK) = 68: 9: 16 kg NPK ha-1, T6 (High NPK) = 90: 9: 24 kg NPK ha-1, T7 (Control)= no fertilizer, T8 (Farmers’ Field Practice, FFP)= 170: 24: 60 kg NPK ha-1] were assigned in randomized complete block design with four replications. According to the experimental results, different rates of N, P and K fertilizer applications had significant effects on panicles per hill, spikelet per panicle, panicle length and filled grain percent in both locations. The highest yield components were observed in T6 (High NPK). In both experiments, the maximum grain yield was found in T6 (High NPK). The second maximum grain yield was obtained from treatment of T1 ( NPK max )which was statistically similar to those resulted from T5 (Low NPK). Among the different rates of NPK fertilizer treatments, there was a highly significant difference on grain yield of Sinthukha rice variety at 1% level. The mean value of grain yield of T4 (NP-K) was not statistically different with that of T8 (Farmers’ Field Practice, FFP) treatment and then yield followed by T3 (NK-P), T2 (PK-N) and the minimum grain yield was observed in T7 (Control). Although the highest fertilizer rates were applied in these experiments of T1 (NPK max), there was no further increasing in grain yield. Increasing the N fertilizer rate for rice plants does not always increase grain yield due to diminishing return