Influence of potassium fertilizer on nutrient accumulation and physiological efficiency of hybrid rice

Fertilizer K experiments were conducted for consecutive 4 years at Jinhua city in Zhejiang province under field condition to study the influence of fertilizer K on nutrient absorb and use efficiency for rice. The results indicated that fertilizer K could promote nitrogen and phosphorus transporting from stem and leaf to panicle in rice plant, therefore, the yield increased. Contrast to the treatment without fertilizer K application, average total N uptake of hybrid rice increased 7.1-9.3 kg/hm2, total P increased 10-2.0 kg/hm2, total K uptake increased 45.3-56.6 kg/hm2 respectively. N and P nutrient use efficiency did not increased and reached to statistically significance, but K use efficiency significantly decreased 26.3%-28.9% compared with inbred rice. Hybrid rices behaved of physiology advantage in nutrient uptake and use efficiency than that of inbred rice. By analyzing annual dynamic change of exchangeable K and nonexchangeable K in testing soil, suggested that hybrid rice depleted more nonexchangeable K in soil than inbred rice. The trend of content of available K in testing soil decreased annually whereas nonexchangeable K increased when fertilizer K were applied.