The study of effects of different nitrogen and potassium levels on yield and mineral elements storage in straw and grain of rice ratoon (Hashemi cultivar)

In order to study the effect of application of nitrogen and potassium fertilizers on rice ratoon yield three an experiment was carried out in 3 rice farms of Guilan Province، Iran. Four levels of nitrogen (N): 0، 50، 100 and 150 kg/ha in form of as well as 0 and 100 kg/ha of potassium (K) in form of potassium chloride were applied on the rice field after harvesting in Astaneh Ashrafiyeh and Amlash (two sites). At the end of growing season grain yield، the weight of straw، nitrogen، potassium and phosphors concentration in straw and grain were measured. According to the results the effect of location on the grain yield، the weight of straw، the phosphors concentration in straw، nitrogen and phosphors concentration in grain، nitrogen agronomical efficiency (NAE) and nitrogen physiological efficiency (NPE) were significant (p<%1). Nitrogen had significant effect on grain yield (p<%1) and of potassium in straw (p< %5). The effect of potassium on grain yield and NAE was significant (p<%1). The results of this research showed that the use of nitrogen and potassium fertilizer increased grain yield and the weight of straw in comparison with no application of both fertilizers. The highest grain yield was observed in N100K100 with 1142 kg/h. There was an intraction between nitrogen and potassium levels and locations on yield of ratoon. Fertilizer treatment N0K100 had the highest straw weight with 305. 81 kg/ha. Potassium had a vital role in the distribution and partitioning of photosynthetic materials among different organs of shoot. In appropriate condition of potassium، the distribution of photosynthetic materials and carbohydrates among different organs of bush will be performed better.