Effects Of Soil Fertility Levels On Rice Yield, Quality And Indexes Of The Precise And Quantitative Nitrogen Application

In the precise and quantitative nitrogen application of rice, the determination of aim yield, annual soil availability nitrogen and annual nitrogen use efficiency had close relation with the soil fertility. Furthermore, in rice production, the formation of high yield and good quality was also closely related to the soil fertility. In this paper, several questions were discussed including the response of rice varieties to different type of soil and soil fertility levels, effects of soil types and fertility levels on the yield, quality and nitrogen use efficiency of rice, analysis and calibration of precise and quantitative N application indexes at different sites. The results were as follows:(1)The responses of different soil types and levels of soil fertility to the growth period and basal yield of grain were obviously various among rice. The basal yield of rice was relatively higher inclay at the high level of soil fertility and it reached to 421.8kg/666.7m~2 in average (Its range was 380.5-469.2kg/666.7m~2). It is higher than 408.5kg/666.7m~2 in sandy soil by3.26%. At the middle level of soil fertility, the basal yields in clay and sandy soil were about equal which were reached above 370kg/666.7m~2. In contrast, it was the highest in sandy soil at the low level of soil fertility. The yield was 344.1kg/666.7m~2 12.01% higher than 307.2kg/666.7m~2 in clay. With the increased level of soil fertility, the basal yield in the same type of soil and different levels of soil fertility enhanced immediately and it was increased by 114.6kg/666.7m~2,64.4kg/666.7m~2 in clay and sandy soil respectively. Basal yield of rice varieties with different growth period increased with the extension of growth period and soil fertility levels. Yield of rice grown in clay was the highest among rice varieties with different types of growth period and it was higher in Indica between two rice...