中国玉米机械粒收质量主要指标分析

Analysis of main quality index of corn harvesting with combine in China

机械粒收是中国玉米生产技术的重大变革与发展方向,团队于2012—2019年在玉米主产区21个省(市区)布设了155个点次的粒收试验与示范,开展适宜机械粒收品种的筛选和粒收质量调查,共测试了865个玉米品种(组合),获取了2987组8961个机械粒收质量样本数据,分析表明,收获籽粒的平均含水率为25.91%,平均破碎率为7.96%,杂质率为1.18%,总损失率为3.54%,其中落穗损失占76.5%,是收获损失的主要部分。对比2012—2015年测试数据,近年我国玉米收获质量得到明显改善,其中,2015年以来收获期籽粒含水率平均每年下降0.78%、破碎率平均每年下降0.51%。与美国玉米收获质量相比,收获时籽粒含水率高9.5%,破碎率、杂质率也明显高于美国。收获质量指标间的相关分析表明,破碎率、杂质率均与籽粒含水率呈极显著正相关,籽粒含水率在19.06%时收获破碎率最低,收获期籽粒含水率高仍是籽粒破碎率高的主要原因。不同生态区间以黄淮海夏播玉米收获时籽粒含水率和破碎率最高、华北春玉米最低,西北和东北春玉米居中。进一步选育脱水快、收获时含水率低、后期站秆性能好的品种,推广品种脱水与区域气候配置技术,改进收获机械,并适期收获是降低破碎率、损失率的主要方向。

Mechanical harvest of corn grains is of major importance for China’s corn production.In this study,we used data from a total of 155 experimental sites to study mechanical grain harvest in 21 major corn producing provinces,cities,or autonomous regions in China from 2012 to 2019.Corn hybrids suitable for mechanical grain harvest were selected and field tests of mechani-cal harvest quality were carried out.A total of 865 corn varieties(hybrid combinations)were tested,and 8961 samples of me-chanically harvested grain were obtained from 2987 tests.The harvested grains were assessed for grain quality to provide a basis for developing mechanical harvest corn in China.Results showed that,on the average,moisture content of harvested grain was 25.91%,grain breakage rate was 7.96%,impurity rate was 1.18%,and loss rate was 3.54%.Additionally,the ear loss accounted for 76.5%of the total harvest losses.Compared with the test data from 2012 to 2015,the quality of corn harvest in China had been significantly improved in recent years,with the average moisture content of harvested grains decreasing by an average of 0.78 percentage point every year and the average grain breakage rate decreasing by an average of 0.51 percent every year between 2015 and 2019.Compared with data of corn harvest of the United States between 2011 and 2019,the average moisture content of harvested corn from the present study was 9.5 percentage points higher,and the breakage rate and impurity rate were also signifi-cantly higher.Further analysis showed that both grain breakage rate and impurity rate were positively correlated with the grain moisture content.Additionally,grain breakage rate was the lowest when grain moisture content was 19.06%.Cross regarding different corn producing regions,the grain moisture content and grain breakage rate were the highest in the Huang-Huai-Hai summer corn region and lowest in the Northern China spring corn region,with medium values in the Northwestern China spring corn region and the Northeastern China spring corn region.The findings suggested that,in China,it was necessary to reduce the grain breakage rate,impurity rate,combine losses,and improve the harvest quality by breeding corn varieties with fast grain de-hydration,low grain moisture content,and strong stalk stand ability at harvest stage,as well as by appropriately matching the dehydration characteristics of corn varieties with regional climate characteristics,improving the performance of harvesting ma-chinery,and harvesting at the most appropriate time.