Effects Of Variety, Nitrogen Fertilizer And Plant Density On Maize Yield And Quality

As a multipurpose crop, maize (Zea mays L.) is very important for grain security, food security and energy security in China. Based on the scientific problem of how to harmoniously increase yield and improve quality, effects of variety, nitrogen fertilizer and plant density on maize yield and quality of grain and stover were researched. The results were showed as follows.Near infrared reflectance spectroscopy (NIRS) calibration models of in vitro dry matter digestion (IVDMD), acid detergent fiber (ADF), neutral detergent fiber (NDF) and water soluble carbohydrate (WSC) of maize stover were established with NIRS technique, partial least square regression (PLS) and data pretreatment of 1st derivative+mean center+Multiple scatter correction. Determination coefficients of calibration about those models were above 0.91. Standard error of calibration, cross validation and prediction ranged from 0.935 to 1.904. All values of relative percent differences(RPD) were greater than 3. It demonstrated that these calibration models could be used to rapidly and accurately predict forage quality of maize stover and screen various samples in maize breeding.The results showed that there were significant differences in grain yiled, crude protein, ether extract, starch and Lys content, stover yiled, IVDMD, ADF, NDF and WSC content among forty varieties. The quality traits were almost accorded with normal distribution respectively. The coefficient of variation of stover WSC content was maximal, and that of grain starch content was minimal. Grain yield was not significantly and negatively correlated with CP, but, it was significantly and negatively correlated with EE and positively correlated with ST. CP was not significantly and positively correlated with EE, but, it was significantly and negatively correlated with ST. There was a significantly negative correlation between EE and ST. Grain yield was not significantly and positively correlated with stover yield, IVDMD and WSC, and was not significantly and negatively correlated with stover ADF and NDF. IVDMD was significantly and negatively associated with ADF and NDF, and positively associated with WSC.Forty maize varieties were classified three clusters through dynamic cluster analysis and varieties include in the third cluster with better integrated traits accounted for 29.55%. Yield and quality traits were two-dimensionally sorted and optimized through the four-quadrant analysis, in this way, maize varieties with excellently integrative traits of Zhengdan958, Shaandan8806, Denghai11 and Dongdan60 were screened out.Two excellent maize varieties of Shaandan8806 and Zhengdan958 were selected to research effects of nitrogen fertilizer and plant density on maize yield and quality of grain and stover.The results showed that applied nitrogen fertilizer under appropriate amount could improve quality and yield. In the range of pure nitrogen from 0 to 337.5 kg/hm2, with increase of applied nitrogen fertilizer, grain and stover yield, and stover IVDMD of two varieties increased, but stover ADF and NDF content decreased. EE and ST content of two varieties, and CP content of Shaandan8806 increased from 0 to 225 kg/hm2 and then decreased, while CP content of Zhengdan958 sostenuto increased.Feasible plant density could improve yield and quality. From 45 000 to 75 000 plants/hm2, with the increase of plant density, stover yield of two varieties, and Grain yield, ADF and NDF content of Zhengdan958 increased, but CP and EE content of two varieties and ST content and IVDMD of Zhengdan958 decreased. Grain yield, ST, ADF and NDF content of Shaandan8806 increased from 45000 to 75 000 plants/hm2 and then decreased, while IVDMD decreased in the beginning and increased. Grain yield, ADF and NDF of Shaandan8806 increased from 45000 to 75 000 plants/hm2 and then decreased, while IVDMD decreased in the beginning and increased.