Research On Maize Seed Dehydration And Its Cultivation Environment Influencing Factors In High Latitude

Northeast China is the most important corn main producing area in China,in recent years,due to the rising demand for corn and grain prices,the corn planting area in Northeast China has been moving north to the third and fourth temperate zones of Heilongjiang Province,through the use of cultivation technology of dense planting of medium and early maturing corn varieties,the yield and production efficiency have been significantly improved,and gradually become an important food crop in the cold and cool area of Northeast China.However,rapid autumn cooling and early frost occur in the cold and cool area of Northeast China,which affects the maturity of maize grain and the dehydration of grain fields,and high grain moisture content and poor maturity at harvest have always been the key problems plaguing maize production in Northeast Cold and Cool District.In this paper,three varieties(Demeiya 1,Demeiya 3 and Heyu 29)were selected in Northeast China,and the sowing test was set up to observe the dynamic change of grain moisture content.Different modeling strategies such as full sowing period and partial sowing period were used to construct a grain moisture content prediction model by using accumulated temperature and moisture content,and the accuracy difference of dehydration models under different strategies was analyzed,and a method for quickly constructing a variety dehydration model was established.Simulated blocking grout was carried out to observe the changes of grain dry weight and moisture content after blocking filling,which provided a theoretical basis for the research on high yield of maize and the adjustment of planting structure in this region.The main results were:(1)Dynamic and characteristic analysis of grain dehydrationIn 2021,the dehydration rates of Demeiya 1,2 and 3 were 0.49 %/d,0.48 %/d and 0.43 %/d,respectively.The dehydration rates of Demeyer 3 sowing period 1,sowing period 2 and sowing period 3 were 0.63 %/d,0.72 %/d and 0.63 %/d,respectively.The dehydration rates of Heyu 29 sowing period 1,sowing period 2 and sowing period 3 were 0.54 %/d,0.57 %/d and 0.58 %/d,respectively.In 2022,the dehydration rates of Demeiya 1,2 and 3 were 0.57 %/d,0.70 %/d and0.65 %/d,respectively.The dehydration rates of Demeiya 3 sowing period 1,sowing period 2 and sowing period 3 were 0.71 %/d,0.67 %/d and 0.61 %/d,respectively.The dehydration rates of Heyu 29 sowing period 1,sowing period 2 and sowing period 3 were 0.61 %/d,0.60 %/d and0.61 %/d,respectively.The dehydration rate before physiological maturity slowed down with the delay of sowing date,and the dehydration rate varied between different varieties and different years.In 2021,the average physiological maturity and harvest water content and natural dewatering rate of each sowing period were lower than those in 2022.(2)Construction of dehydration modelIn the dehydration models of Demeyer 1 and Demeiya 3 varieties constructed by different modeling strategies,there was no significant difference in model parameters and simulation accuracy with the increase of the number of sowing periods participating in the modeling,and the variability of model parameters gradually decreased.Combined with the grain moisture content data of the same varieties measured in 2021 in Tongliao,Tieling and Gongzhuling accumulated by the research group,the model established by different strategies was tested in three sites in the northeast spring maize area,and there was no significant difference in model accuracy,and the RMSE value was between 2.76～2.88 %.A robust variety model can be constructed by using the staged sowing method,which has stable prediction accuracy between years and regions,and the RMSE value verified by the model between regions accelerates the construction of maize variety dehydration model,which provides a powerful theoretical tool for evaluating the suitability of mechanical harvesting of varieties.(3)Blocking grout testDemeiya 1,Heyu 29 and Zhengdan 958,the dry weight of the kernels was distributed in a line after the blocking of the germplasm at different days after spatulation by both picking and post-picking freezing,and the later the blocking of the germplasm,the higher the dry weight of the kernels and the higher the moisture content of the kernels.The rate of dehydration in the blocked kernels was higher than that of the normal growing plants in the field for the same period of time,with the rate of dehydration decreasing as the blocking was delayed.The blocked grouting experiment illustrates that without the maintenance of grouting stability,the rate of dehydration under environmental influence is faster than that of normal growth.