Effect of harvesting methods and grain moisture content on maize harvesting quality

In China, maize crops are harvested about 35.93% underplanting area and 39.16% share of the total yield. Maize grains are the most significant concerns during the harvesting stage for the further process towards foods yield for the designing of the harvester, thresher, handling, processing, and storage equipment. The maize grain harvesting quality is affected by maize variety characteristics, dehydration rate after physiological maturity and grain moisture content, etc. Therefore, the harvesting area of maize grain harvesting only accounts for 5%-6% of the total maize production area though maize grain harvesting technology is the key technology of modern production of maize and a developing direction of maize harvesting. Therefore, the present research was planned to analyze the effect of harvesting techniques (maize harvesting and maize grain harvesting), moisture content (17.62% to 32.12 %) and thirteen maize grains varieties (ZD958, XYu335, DH605, DH618, NH101, WK702, JD29, LD818, LD9066, XY218, LD9088, LD9151, LD2016) on maize harvesting quality. Further, cluster falling rate, grain falling rate, grain broken rate and rate of chips were assessed during harvesting time. The results revealed that the grain moisture content of maize varieties decreased significantly (P<0.05) from 32.12% to 17.62% towards the normal and delayed harvesting periods, but the change rates of grain moisture content among maize varieties were different. The total harvesting loss rates were 2.59% and 3.28% observed towards maize harvesting and maize grain harvesting, and there was no significant difference (P>0.05) found between maize harvesting and maize grain harvesting. The cluster falling rate occupied 75.28% (maize harvesting) and 54.53% (maize grain harvesting) of total loss rate. Furthermore, the mechanical harvesting method significantly (P<0.05) affected grain falling rate during the normal harvesting time, grain falling rate and cluster falling rate decreased significantly (P<0.05) during the delayed harvesting time. There was no significant correlation between grain moisture content and loss rates (including total loss rate, cluster falling rate and grain falling rate) when maize harvesting was adapted. As for maize grain harvesting, there was significant correlations between grain moisture content and grain falling rate, total loss rate, broken rate, rate of chips. Further, the average rate of chips, total loss rate and broken rate (1.32%, 1.74%, and 13.23%) were found under the delayed harvesting period. Thus, results revealed that the average rate of chips and total loss rate was observed not higher than the national standard requirements of 3% and 5%, whereas the average broken rate was observed higher than the national standard requirement of 5%. The linear relationship between the rate of chips and the grain moisture content was developed. According to the relationship, the rate of chips can meet the national requirement if the grain moisture content rate is less than 32.40%. Therefore, it is concluded that the delayed harvesting period would minmize the losses of harvesting and provide a guideline to farmers for harvesting the grains on the appropriate time. This study can provide data support and scientific basis for the research and popularization of maize grain harvesting technology.