Effects of different proportions of nitrogen and potassium amounts on the nitrogen absorption and utilization in the direct-seeded rice

Under the condition of different proportion of three nitrogen amounts with three potassium amounts,the effects of different proportions of nitrogen and potassium amounts on the nitrogen absorption and utilization were discussed. The result indicated: the total accumulation and utilization of nitrogen were the highest in the N 2 K 3 treatment. At the same nitrogen level,the nitrogen accumulation increased with potassium fertilizer amount,there were significant differences among different treatments. The nitrogen accumulation showed no significant difference when the nitrogen amount was 165 kg / hm2and 210 kg / hm2at the same level of potassium fertilization. The increase of nitrogen and potassium amounts was conducive to raising nitrogen accumulation before the panicle differentiation stage of direct-seeded rice. The increase of nitrogen and potassium amounts was conducive to raising the nitrogen distribution proportions in vegetative organs,and nitrogen distribution proportion in panicle decreased with increase of amount of potassium applied. The nitrogen translocation rate and contribution rate of each organ nitrogen to grain increased with the increase of nitrogen fertilizer amount. The nitrogen transport rate of leaf and sheath declined with increased amount of potassium fertilizer at the level of nitrogen fertilizer of 120 kg / hm2and 165 kg / hm2. Potassium fertilizer had obvious influence on the nitrogen translocation rate at the level of nitrogen amount of 210 kg / hm2. The activites of NR,GOGAT,GS increased with nitrogen fertilization before heading. The activity of nitrogen metabolism enzyme of N 2 treatment was the highest usually after heading. The activites of NR,GOGAT,GS increased with potassium fertilizer. The nitrogen agronomy utilization ratio of N 2 was the highest at three nitrogen fertilizer levels. Increase of potassium fertilizer amount improved the utilization rate of nitrogen with the same amount of nitrogen fertilization,this effect was significant at low nitrogen levels. The increase of fertilization amount of nitrogen and potassium decreased the harvest index of nitrogen. 165 kg / hm2of nitrogen and 210 kg / hm2of potassium made the best coordination group for cultivation of direct-seeded rice.