The Effect Of Different Nitrogen Rate On The Formation Of Bowl Mechanical-transplanting Rice Yield And The Absorption And Utilization Of NPK

The experiment was conducted in the outside experimental base of agriculture college of Yangzhou university during 2013 to 2014, taking two conventional rice Wuyunjing24 and Wuyunjing30, and two hybrid rice Yongyou1640 and Yongyou 2640 as materials, setting six nitrogen levels (0,12.5,15,17.5,20,22.5kg/667m2), simulating nutrition bowl mechanical-transplanting,and setting the conventional blanket seedling mechanical-transplanting as control. On this basis, we studied the effect of different nitrogen levels on the rice yield formation and the absorption and utilization of N, P and K. In addition, the advantage of nutrition bowl mechanical-transplanting rice yield formation had been studied.All of these are aimed to find a proper nitrogen applying level, thus to provide theoretical basis for local bowl mechanical-transplanting rice planting and promote the nutrition bowl mechanical-transplanting application. The main results are as follows:1. With the increase of nitrogen applying, the yield of different rice increased first and then decreased, the highest yields are all in the level of 20N. In the early and middle growth, the tiller number increased with the increase of nitrogen applying, while at the mature stage increased first and then decreased, the highest number was in 20N level. When the nitrogen level reached 22.5N, the spike rate decreased significantly. The dry matter accumulation during transplanting to jointing and jointing to heading increased with the increase of nitrogen level, while at heading to mature reaching highest at 20N and then decreased significantly. The leaf area at jointing increased with the increase of nitrogen level, but the high efficient leaf area at heading was highest at 20N and then decreased significantly, the mature leaf area was same as the high efficient leaf area. The crop growth rate was highest at jointing to heading and increased with the increase of nitrogen level before jointing, while at jointing to heading and heading to mature increased first and then decreased, the highest crop growth rate was at 20N level.2. The ratio of N accumulation was highest at jointing stage, and the second was at heading, the lowest was at mature. The ratio of N accumulation and N accumulation at jointing, heading and mature increased with the increase of nitrogen level. The N accumulation was highest at jointing to heading stage except ON level. Before jointing stage and at jointing to heading stage, the N accumulation increased significantly with the increase of nitrogen level, while at heading to mature increased first and then decreased. The total N accumulation also increased significantly with the increase of nitrogen level. The N utilization rate increased first and then decreased with the increase of nitrogen level, the conventional rice was highest at 20N level while the hybrid rice was highest at 17.5N level. The agronomic nitrogen use efficiency and physiological use efficiency decreased after 20N level. The bias productive forces of nitrogen fertilizer decreased with the increase of nitrogen level and the difference between every treatment was significant. N absorption of 100kg seeds was increased with the increase of nitrogen level. The speed of N accumulation was highest at jointing to heading and lowest at heading to mature. Before jointing, the speed of N accumulation increased with the increase of nitrogen level, while at jointing to heading and heading to mature increased first and then decreased, the quickest was at 20N level.3. The P accumulation and the ratio of P accumulation presented the same trend, they all increased with the increase of nitrogen level at jointing and heading, while at mature they decreased after 20N level. The P accumulation amount was highest at jointing to heading, the second was at heading to mature and the lowest was before jointing. The P accumulation amount before jointing and at jointing to heading increased with the increase of nitrogen level while at heading to mature increased first and then decreased. The speed of P accumulation is highest at jointing to heading, the second was at heading to mature and the lowest was before jointing. Before jointing, the speed of P accumulation increased with the increase of nitrogen level, while at jointing to heading and heading to mature increased first and then decreased, the quickest was at 20N level.The K accumulation and the ratio of K accumulation presented the same trend, they all increased with the increase of nitrogen level at jointing, while at heading and mature increased first and then decreased. The K accumulation amount was highest at jointing to heading, the second was before jointing and at heading to mature only absorbed little K. The K accumulation amount increased with the increase of nitrogen level before jointing and at jointing to heading and heading to mature, the highest value was at 20N level. The speed of K accumulation was quickest at jointing to heading, the second was before jointing and the slowest was at heading to mature. Before jointing, the speed of K accumulation increased with the increase of nitrogen level, while at jointing to heading and heading to mature increased at first and then decreased significantly at 20N level.4. In the aspect of the composition of yield, the grain number per panicle,1000-grain weight and seed setting rate had little difference between nutrition bowl mechanical-transplanting rice and conventional blanket seedling mechanical-transplanting rice, while the ears per mu of nutrition bowl mechanical-transplanting rice was higher at every nitrogen level and the dry matter accumulation was the same. At the highest nitrogen level, the spike rate of nutrition bowl mechanical-transplanting rice was higher than conventional blanket seedling mechanical-transplanting rice. The leaf area of conventional blanket seedling mechanical-transplanting rice was lower than nutrition bowl mechanical-transplanting rice at every nitrogen level when heading, because the high efficient leaf area of nutrition bowl mechanical-transplanting rice was higher and the same was the leaf area at mature. The crop growth rate of nutrition bowl mechanical-transplanting rice was also higher at every nitrogen level.