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Variation in Corn Stover Yield and Fuel Quality with Harvest Time

The objective of this investigate is to evaluate the variation in yield and fuel quality of corn stover under different harvest time and to determine appropriate harvest time. Using Zhengdan 958 as research material, the effect of harvest time on yield and fuel quality of corn stover was studied under field conditions in Baicheng Academy of Agricultural Sciences, during 2007-2008. Results showed that with the delayed harvest time, yield of corn stover decreased, and the proportion of leaves reduced gradually, reduction of leaf biomass was the main reason for lower yield. With the delayed harvest time, moisture, ash, and mineral elements contents of corn stover significantly decreased, cellulose and lignin contents increased, but hemicellulose content decreased. Heating value of corn stover was maximum at filling stage and minimum at maturity, it was slightly higher after maturity. Heating value was significantly correlated with cellulose and lignin contents; ash content was significantly positively correlated with mineral elements contents, and was significantly negatively correlated with Si/K ratio. Delayed harvest reduced the yield of corn stover, but significantly improved its fuel quality. Fuel quality of corn stover was better when harvested in winter and spring.