黄土高原旱作玉米籽粒水分与机械粒收质量的关系

玉米机械粒收是全程机械化的关键,但存在着籽粒破碎、果穗和落粒损失严重等备受关注的问题。开展机械粒收质量及其影响因素研究,对推进旱作玉米机械粒收技术应用具有重要意义。本研究选择国内玉米主栽品种33个,于2016–2017年在甘肃泾川同一地块上用福田雷沃谷神收割机械粒收,分析籽粒水分与机械粒收质量指标的关系。结果表明,基因型差异是造成玉米机械粒收质量不同的主要原因,两年收获时平均籽粒水分26.05%,破碎率7.47%,产量损失率3.25%,落穗损失率2.58%,杂质率1.04%;籽粒水分(X)与破碎率(Y1)、产量损失率(Y2)显著正相关,并且存在Y1=0.027X2–0.987X+14.06(R2=0.373**,n=51),Y2=0.052X2–2.223X+24.86(R2=0.418**,n=51)的变化关系,籽粒水分依次下降到18.3%、21.4%时,对应的破碎率(5.1%)、产量损失率(1.1%)最低,即在一定含水率范围内随着籽粒水分的增加破碎率、产量损失率升高,机械粒收的籽粒适宜水分为18%~22%,破碎率可控制在5.0%~5.5%的范围内;籽粒水分对落穗损失的影响大于落粒损失,随着籽粒水分增加落穗损失率增加的幅度明显高于落粒损失率的升高;各因素对玉米机械粒收产量损失的影响为:落穗损失率(0.924)籽粒水分(0.048)破碎率(0.043),因而籽粒水分高和落穗损失量大是影响黄土高原旱作玉米机械粒收质量的主要因素。

Relationship between Grain Moisture and Maize Mechanical Harvesting Qualities in Dry Highland of Loess Plateau

Grain harvesting is a key process in whole mechanization of maize, and grain breakage and ear and kenenal losses have attracted more and more attention, therefore studying on maize mechanical harvesting qualities and its related factors has very important practical significance for promoting maize grain harvesting techniques in dryland. From 2016 to 2017, 33 maize varieties were used under full film mulched ridge-furrow planting system at Pingliang, Jingchuan county to harvest grain with Futian leiwo Ceres harvester for determining relationship between grain harvesting qualities and grain moisture. Grain harvesting qualities highly depended on maize genotypes, the average values were 26.05% in grain moisture content, 7.47% in grain broken rate, 2.58% in ear loss rate, 1.04% in impurity rate, and 3.25% in total grain loss rate. Grain broken rate (Y₁) and total grain yield loss rate (Y₂) were significantly and positively correlated with grain moisture content (X), expressing as Y₁ = 0.027X ²-0.987X+14.06 (R ² = 0.373 ^**, n = 51) and Y₂ = 0.052X ²-2.223X+24.86 (R ² = 0.418 ^**, n = 51). When grain moisture content declined to 18.3% in Y₁ and 21.4% in Y₂, grain breakage rate and grain loss reduced to minimum value of 5.1% and 1.1%, respectively. When the suitable grain moisture for mechanical harvesting was 18%-22% in the broken rate was in a range of 5.0%-5.5%. In a certain range of grain moisture content, grain broken rate and grain loss rate increased with the increase of grain moisture content. Effect of grain moisture on ear loss rate was higher than that on kernel loss rate, and the increasing extent of ear loss rate along with grain moisture was much higher than that of kernel loss rate. The effect of problem factors in maize mechanical harvesting on total grain loss was era loss rate > grain moisture > broken rate, showing that high grain moisture content and high ear loss are main factors affecting maize mechanical harvesting qualities in dryland.