Responses Of Rice Quality Parameters To Nitrogen Application Under Different Ecological Conditions

Rice is one of the most important food crops in China and rice quality is directly related to the competitiveness of rice in the market and to the living standard of Chinese people. This study was carried out in 2003 and 2004 to investigate the response of rice quality parameters to nitrogen application under different ecological conditions. Two factors were designed in this study, one was nitrogen rates and the other was ecological conditions including rice cultivar, transplanting timing, green manure and straw application and atmospheric CO2 elevation. The milling, appearance, nutritional and cooking quality and the parameters in RVA profile of rice starch were measured for different treatments. Following results were obtained(1) Free-air CO2 enrichment (FACE) reduced the percentage of head rice and the content of protein, and increased the chalkiness and amylose content of milled rice, which caused the degradation of milling, appearance, cooking quality of rice. The peak, holding and final viscosity in RVA profile of rice starch was significantly higher under FACE treatment than that under ambient condition (CK) and peak time delayed under FACE condition, but FACE had little impact on breakdown and setback value. Nitrogen application improved the milling quality, increased protein content and reduced amylose content of rice, under both FACE and ambient condition. Nitrogen application also reduced peak, holding and final viscosity and peak time in RVA profile, but RVA profile was more sensitive to nitrogen application in ambient than that in FACE. The effect of...