Effect Of Harvesting Time And Stubble Height On Silage Quality Of Whole Plant Corn In Northeast China

This experiment was conducted at five time points in September 2021,harvesting whole maize at three different stubble heights(20cm,40 cm,60cm)from five different latitudes in Northeast China(Shenyang,Changchun,Tongliao,Harbin,and Qiqihar),followed by silage fermentation.After 280 days of fermentation,nutritional indicators(DM,CP,Starch,ADF,NDF)were measured Determination of fermentation indicators(p H,lactic acid,acetic acid,propionic acid,butyric acid,NH3-N)and hygiene indicators(DON).Determine the optimal stubble height and harvesting time by comprehensively considering factors such as nutritional indicators,fermentation indicators,hygiene indicators,and silage yield.The results showed that:(1)The vomiting toxin of whole plant corn silage in Northeast China showed an exponential change with the delay of harvest time,and a linear change with the increase of stubble height.(2)The vomiting toxin of whole plant corn silage in Northeast China increased by 1.90% per day at a stubble height of 20 cm,2.36% per day at a stubble height of 40 cm,and 2.90% per day at a stubble height of 60 cm.And the vomiting toxin of whole plant corn silage in Northeast China decreased by 22.25% with every 20 cm increase in stubble height.(3)The DM content of whole plant corn silage in Northeast China showed a linear change with delayed harvest time,while the CP,Sta,ADF,and NDF content showed a univariate quadratic change with delayed harvest time.(4)The suitable harvesting time for whole plant corn silage varies in different regions,with an overall concentration from September 14 th to September 22 nd.(5)The nutritional indicators of whole plant corn silage in Northeast China increase by 20 cm with stubble height,6.13% with DM,6.63% with CP,4.31% with starch,7.50% with ADF,and 5.31% with NDF.(6)The fermentation indicators of whole plant corn silage in Northeast China show a quadratic variation with the delay of harvest time.(7)The suitable harvest time for the fermentation indicators of whole plant corn silage in Northeast China is from September 9th to September17 th.(8)The fermentation indicators of whole plant corn silage in Northeast China decreased by2.09% for every 20 cm increase in stubble height,LA increased by 2.78%,and ammonia nitrogen decreased by 25.48%.To sum up,when determining the harvesting plan,the latest harvesting time shall be determined according to the accumulation law of DON in different regions and the limited range of silage DON,and then the optimal harvesting time shall be determined by comprehensively considering the nutrition index and fermentation index.Finally,the optimal stubble height for harvesting shall be determined according to the lactation value.