Studies On The Feasibility Of Maize Mechanically Harvesting Grain In Huanghuaihai Regions

Maize is currently China’s very important crop with the largest planting areas and the highest total yield. The whole course mechanization is the developing direction of modern maize production. Maize harvest is the most heavy part of maize production, and it currently is the bottleneck of the whole process of maize production mechanization. At now maize mechanical harvesting rate is low, and the harvesting equipment is mainly for ear harvest, and the proportion for mechanical harvesting of maize grain is lower in current maize harvest. At present, there are few studies on the field of mechanical grain direct harvesting in China. The different quality indicators of maize grain harvesting machinery at different sites was studied in four sites of Huanghuaihai regions(including Linying county, Xinxiang city, Henan province, Chiping county, Shandong province, and Cixian county, Hebei province), using different genotypes of maize varieties, by scientific experimental design, using the appropriate test methods. At the same time, the related factors influencing the grain harvest were studied by analysis of meteorological factors and different varieties at different sites. The results were showed as follows:1. With the improvement of grain moisture content the grain broken rate increased, and the difference reached significant level. So, grain broken rate is an very important index for the evaluation of grain harvest quality. Grain impurity rate increased with the water content of grain, but showing a range of different at different sites. At the site of Linying county, Henan province, the variation of impurity rate is far lower than the other three sites. The loss rate of grain was relatively low in four experimental sites. Although within the scope of all test sites the loss rates were increased with the water content of grain, the relative grain broken rate and impurity rate were not obvious, especially in Chiping county of Shandong province, the grain loss rate and grain moisture content did not reach the significant correlation. In the experimental range, the grain loss rate in the four sites of the vast majority of sample points can reach the national standard, and further confirmed, loss rate was the key factor affecting the grain harvest quality evaluation.2.The experiment results showed that, the yield loss rate of mechanical grain harvesting in the four sites was far lower than the national standard of GB/T 21962-2008; when the grain moisture content below 28.27%, impurity rate could reach the requirements of the national standard of 3% In Xinxiang under the conditions no natural disasters, using suitable varieties and reasonable arrangement of sowing date; When it was lower than 26.96%, broken rate could meet the requirements of the third degree of maize quality.3.When AT of test varieties in the whole growing period reached 2932 degree·day(dd), grain moisture content could be reduced to below 26.96%, meet the quality requirement for mechanical grain harvest. The average AT was 3099 dd in Xinxiang city during 20 years(1994-2013) from June to September, even taking the delay in sowing time into account, its still fully met the requirement of low grain moisture content. Appropriate postpone the maize harvest time was not only meet the technique demand of high yielding maize, but also increase the quality for mechanical grain harvest, under the conditions that the next season winter wheat sowing was not affected.4.There were about 6 maize varieties of Xianyu 335, Zhengdan 958, Liangyu 66, Zhongzhong 8, Dika 517 and DL11016 were selected In Xinxiang experimental site, and the difference of the quality of mechanical grain harvest was studied. There were obvious differences in descending process of maize grain moisture among different varieties. Under the experimental conditions, Xianyu 335, Dika 517, DL1101, and Zhongzhong 8 all had the ability of rapid dehydration to meet grain direct harvesting under relatively low temperature conditions, while for Zhengdan 958 and Liangyu 66 with relatively slowly dehydration, they need higher AT, and It is very difficult to meet the requirement of the mechanical grain harvest in Xinxiang city.