Effects of N and K Applications on Agronomic Characteristics of Two Iranian and Landrace Rice (Oryza sativa L.) Cultivars

Abstract

Nutrition elements like nitrogen and potassium are restricting yield performance of rice cultivars and affecting on their characteristics. In order to consider effects of different amount of nitrogen and potassium on yield and chemical compounds of two rice cultivars (Tarrom and Neda which are landrace and improved Iranian genotypes, respectively), current experiment has been undertaken in 2004 and 2005. Four levels of nitrogen fertilizer (0, 50, 100 and 150 kg N ha(-1) from urea source) and four levels of potassium fertilizer (0, 75, 150 and 225 kg K2O ha(-1) from potassium sulfate source) have been applied in a split-factorial based on randomized block design with three replications. Nitrogen fertilizer has been applied in three different stages of plant growth (1/3 in transplanting, 1/3 in tillering and 1/3 in flowering initial stages) and potassium fertilizer has also been applied in two growth stages (1/2 in transplanting and 1/2 in shooting stages). Results indicated that application of nitrogen has increased plant height, number of tiller, length and width of flag leaf, length of panicle, number of grain per panicle, grain yield, amount of dry matter, biological yield, harvest index, leaf potassium, leaf nitrogen, 1000 grain weight and reducing percentage of hallow grain. Also, applied potassium has positive effects on all of above mentioned yield components except harvest index and 1000 grain yield. Neda cultivar was better than Tarrom genotype for most of the measured traits. Interaction of nitrogen and potassium were affected significantly on number of tiller per plant, grain yield, amount of dry matter and biological yield in Neda cultivar and on length of flag leaf, number of grain per panicle, grain yield, amount of dry matter, biological yield, harvest index and 1000 grain yield in Tarrom genotype.