饲用玉米器官含水率、力学强度与籽粒机收质量的关系研究

在玉米正常收获期间,明确器官含水率、力学强度和机收质量的变化规律,探明影响籽粒机收效果的直接因素,对实现玉米籽粒机收和提升机收质量具有重要意义。本试验以两个不同熟性品种为材料,采用半喂入式籽粒收割机,开展分期收获的田间试验研究。结果表明,籽粒静态压碎强度(耐破碎性)和籽粒与穗轴连接强度(易脱粒性)分别与籽粒破碎率形成了直接的因果关系,两者同是影响破碎率的关键因素。籽粒压碎强度(x)与破碎率(y)可高度拟合为二项式回归关系(R²=0.8827,P<0.001),回归方程为$\hat{y}$=0.0021x²-1.5443x+293.78,籽粒和穗轴连接强度(x)与破碎率(y)可高度拟合为幂函数型回归关系(R²=0.7656,P<0.001),回归方程为$\hat{y}$=0.007x^4.12,而穗轴弯折强度与破碎率之间的关系小于上述(R²=0.1644,0.010.05)。落地籽粒损失率除了与植株倒伏倒折有关以外,对刀式割台容易在果穗脱粒前产生落地籽粒损失,并且越容易脱粒的籽粒损失越大,籽粒含杂率总体上随杂质器官含水率的下降而显著降低。适宜籽粒机收的玉米品种应具备的主要特征是茎秆坚韧抗倒伏、籽粒坚硬易脱粒。

Role of grain crushing resistance and grain threshing characteristics in determining suitability of feed maize cultivars for machine harvesting and effect of plant moisture content

This research studied the role of selected mechanical properties of grain and cob (in particular grain crushing resistance and the detachment resistance of grain on the cob) and plant and cob moisture content in determining suitability for machine harvesting in feed maize. This information is important for improving harvest outcomes for feed maize crops in Southwest China. An early and a late maturing cultivar were tested. The experiment involved a mechanical harvester and a large field study. It was found that the grain crushing resistance (CR, force required to crush grains) and detachment resistance (DR, force required to detach grains from the cob) directly affected the percentage of broken grain (%BG). The relationship between %BG and CR could be described by the quadratic regression relationship: $\overline{\%BG}$=0.0021CR²-1.5443CR+293.78 (R²=0.8827, P<0.001), and the relationship between %BG and DR by a power regression relationship: $\overline{\%BG}$=0.007DR^4.12 (R²=0.7656, P<0.001). The relationship between %BG and crushing resistance of the cobs was much lower than the aforementioned (R²=0.1644, 0.01