玉米子粒机械收获破碎率研究

Grain Breakage Rate of Maize by Mechanical Harvesting in China

子粒破碎率是评价玉米子粒机械收获质量的重要指标。2011-2016年在全国16省(市、区)194个地块开展子粒机械收获质量测试,对获取的2450组样本数据的统计表明,当前玉米子粒机械收获破碎率均值为8.56%,高于国标["玉米收获机械技术条件"(GB/T 21961-2008)]≤5%的要求,破碎率偏高是我国玉米子粒机械收获存在的主要质量问题。破碎率与收获时玉米子粒含水率呈极显著正相关,2450组样本子粒含水率平均值达到26.65%,两者呈二次多项式关系,水分偏高是导致当前我国玉米子粒收获破碎率高的主要原因;不同收获机械及其作业对子粒破碎率也会产生显著影响;此外,玉米生育和收获期间生态环境因素、栽培措施对破碎率也有影响。培育早熟、脱水速率快、收获期含水率低及抗破碎性好的品种,研发推广破碎率低的收获机械和选择最佳收获期收获是解决破碎率高的主要措施,而在收获时根据玉米生长、成熟和子粒水分状况及时检查与调试收获机械参数也有助于降低破碎率。

Grain breakage rate is an important indicator to evaluate the harvesting quality for maize combine harvester. From 2011 to 2016, the harvesting quality of maize combine harvester was tested in 16 provinces of China, and 2450 test samples of grain mechanical harvesting were obtained. Results showed that the grain breakage rate was 8.56%, higher than the national standard of 5% [＂Technical requirements for maize combine harvester＂（GB/T 21961-2008）]. The most significant problem of maize grain mechanical harvesting quality is high grain breakage rate in our country. Further analysis of the influencing factors on the grain breakage rate indicated that there was a very significant positive correlation between the grain breakage rate and the grain moisture content, and their relationship could be fitted with the equation： y_（grain breakage rate） =0.0346x^2-1.3325 x ＋18.5640（R^2=0.3982＊＊, n =2450）. The average moisture content of grain of 2450 group samples reached 26.65%. High grain moisture content was the main factor that led to the high grain breakage rate in maize combine harvesting. The results indicated that different combine harvester and its operation had significant effects on grain breakage rate. In addition, ecological and environmental conditions during maize growth, harvesting, and cultivation measures also influenced grain breakage rate. The main measures to solve the problem of high grain breakage rate include breeding maize varieties having characteristics of early maturity, fast dry-down rate of kernel, low water content of grain at physiological maturity, and resistance to breakage; the research and development of maize combine harvester with low grain breakage rate; and harvesting at optimal time. Furthermore, adjusting harvester parameters based on the growth condition, maturity levels, and grain moisture content before harvesting will also be the measures for reducing the grain breakage rate.