Effect Of Harvesting Time On Maize Mechanized Grain Direct Harvesting Quality And Grain Quality

Maize was the largest planting area and the highest total yield crop in Inner Mongolia,which has ensured food security.In order to improve the mechanical grain harvest quality and grain quality of maize,different varieties suitable for harvesting using as materials,it was to study the changes of maize yield,grain harvest quality and grain quality at different harvest times,and to clarify the reasonable harvest period of varieties suitable for harvesting,under the demand background of maize high yield and high efficiency in our region.At the same time,the response of grain harvest quality and grain quality with different planting densities to harvest times was studied,and the reasonable harvest time of different densities was defined,which provided theoretical reference for the development of maize mechanical grain harvesting industry in the district.The results of the study were as following.Grain moisture content and impurity rate decreased,and ear fall rate and yield loss rate increased,and grain breakage rate and grain fall rate decreased and then increased which were the lowest values at 21 days after physiological maturity,with the harvest time delayed.The top grain puncture strength and embryo puncture strength showed an increasing trend when delaying the harvest time.The contents of crude protein and crude fat in maize grain were the highest at physiological maturity stage,and they declined faster between 21d and28d.The maize yield increased by 12.11%-16.93%after 21 days of physiological maturity,compared with that of physiological maturity.With the planting density increased,there was not significant decrease for the grain breakage rate,and the impurity rate,ear fall rate and yield loss rate showed an increasing trend,and the grain fall rate decreased and then increased.The grain crude starch content increased trend,and grain bulk density,crude protein and crude fat decreased with planting density increased.The highest yield was achieved when the planting density was 120 000plants ha^-1.Based on the growing conditions in Tumed plain irrigated area,the maize grain nutrient quality decreased rapidly from 21d to 28d after physiological maturity,and the grain fall rate and breakage rate were the lowest at about 21d after physiological maturity.It suggested that the harvest time should be around 14-21d after physiological maturity by comprehensive analysis,when the water content was in the range of 20.13%-22.26%,and the grain breakage rate ranged from 2.17%to 2.87%,and the grain breakage rate ranged from 0.23%to 0.42%,and the grain yield loss rate ranged from 2.15%to 3.16%.Therefore,it was suggested that the suitable time of mechanical grain harvesting for different varieties and different densities was about 14-21d after physiological maturity.The variety test is in progress,The characteristics of Xianyu 1619,C1563,Dika 159 and KWS9384 were superior to those of A2636.In the density test,The recommended planting density of Dika 159 is 120000 plants ha^-1.