Effect Of Application Of Nitrogen And Potassium At Different Leaf Age Period On Yield And Population Quality Of One-season-medium Rice

The experiment was carried in Fengtai County Rice Original Seed Farm , Anhui Province from 2007 to October 2008. Japonica Wandao68 was used as material to study effect of application of nitrogen and potassium in different leaf-age-period on grain yield and population quality. The results are as follows:1.On the base of the same amount of basic fertilizer ,yields of treatments with N, K top-dressing at all leaf ages were more than CK increased significantly, The yield of applying N at the third leaf age from top was tiptop (11111.2 kg/hm2), the fifth leaf from top was followed (A5, 11055.6 kg/hm2).Their yields increased by 32.6 percent and 34.4 percent respectively compared with CK1 .So the third leaf age from top is efficient N topdressing leaf-age period. In experiment of K, the yield of applying K at forth leaf age from top (B4) was significantly higher than other processing, reached 11076.5 kg/hm2,which increased 40.5 percent than CK2, the forth leaf age from top is efficient K topdressing leaf-age period.The panicles and grains per panicle were at most when applying N at the third leaf age from top. The seed setting rate was at most at the first leaf age from top and lowest was at forth leaf age. The effect of 1000-grain weight was not significantly on every top-dressing treatments of N. It's beneficial for increasing of grains per panicle and seed setting rate on every top-dressing treatments of N. While the grains per panicle and seed setting rate decreased gradually with postponing the date of K top-dressing. The effect of panicle and 1000-grain weight was not significant on every top-dressing treatments of K.2, The total stems and tillers decreased gradually with the postponing the date of N top-dressing, and ultimately the panicle decreased. The total stems and panicle bearing rate deceased with postponing the date of K top-dressing.3, The Max LAI of population increased gradually with postponing the date of N topdressing. The effective LAI, high effective LAI , percentage of effective LAI and high effective LAI were at most on N topdressing at third leaf age from top which with the lowest ineffective LAI. The Max LAI of population was at most on N top-dressing at fifth leaf age from top which with the highest ineffective LAI. The effective LAI and high effective LAI decreased with extinction of ineffective LAI gradually. It's beneficial for advancing effective tillers ,increasing the effective LAI and high effective LAI and improving the quality of leaf-source.4, The production on dry matter in heading stage and percentage to total dry matter weight after heading stage were higher than any other treatments on N top-dressing at third leaf age from top(A3) and on K top-dressing at forth leaf age from top .5,The total spikelets of population and the ratio of grain weight to leaf area increased gradually with the advance of date on N top-dressing .It's beneficial for increasing yield. While the yields with insufficient total spikelets of population which caused few sink storage were not high because the date on N top-dressing (A1,A2)were too late. The total spikelets of population and the ratio of grain weight to leaf area were higher obviously than other treatments on K top-dressing leaf age from top. So it's beneficial for optimizing population quality, raising sink storage and coordinating sink-source relationship to apply K ahead of time.6, The plant height, panicle length and neck-panicle node height were significantly increased on N top-dressing . The plant height and panicle length increased significantly most on N top-dressing at forth leaf age from top. The neck-panicle node height, percentage of the neck-panicle node height to plant height and the neck-panicle node height and panicle length to plant height were highest on N top-dressing at third leaf age from top. The differences of plant height, panicle length and neck-panicle node height were not significantly but increased significantly compared to CK2 on K top-dressing at every leaf age.In conclusion, N top-dressing at third leaf age from top and K top-dressing at forth leaf age from were high effective ear-fertilizer period Application of ear-fertilizer reasonable could control the inefficient tiller growing, increase the number of total spikelets, improve the effective leaf area percentage and high effective leaf area percentage ,increase grain-leaf ratio, coordinate the relationship of ear and grain. It also could establish the plant type of resistance to lodging and improve the elevation of photosynthetic efficiency from heading to maturing to achieve high yield. It also could establish the reasonable plant type and improve the elevation of photosynthetic efficiency from heading to maturing to achieve high yield.