Welcome to Acta Prataculturae Sinica ! Today is Share:

Acta Prataculturae Sinica ›› 2020, Vol. 29 ›› Issue (9): 125-135.DOI: 10.11686/cyxb2019517

Previous Articles     Next Articles

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

LEI En1,2, SHAO Di2, ZHU Tian-biao2, SHU Xing2, YANG Yong-bing3, WANG Yue-dong3, TANG Qi-yuan1,*   

  1. 1. College of Agronomy, Hunan Agricultural University, Changsha 410128, China;
    2. College of Life Science and Technology, Honghe University, Mengzi 661199, China;
    3. Agricultural Maechinery Research Institute of Yunnan Honghe Hani and Yi Autonomous Prefecture, Mengzi 661100, China
  • Received:2019-11-26 Revised:2020-03-25 Online:2020-09-20 Published:2020-09-20

Abstract: 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: $\overline{\%BG}$=0.007DR4.12 (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<P<0.05). In the later stages of maturation, although the DR of early maturing cultivar ‘JY99’ was significantly lower than that of late maturing cultivar ‘BY9’, the grain crushing strength of ‘BY9’ was significantly higher than that of ‘JY99’, so that these two factors cancelled each other, leading to there being no significant difference in %BG between the two cultivars. In addition to these relationships there was also an association between plant lodging and grain loss; the stripper rotor of the header harvester readily caused grain loss before ear threshing. Further, the grain loss was greater when grains were easy to thresh. Overall, grain impurity rate significantly declined as the water content of the non grain organs reduced. A maize cultivar suitable for mechanical grain harvesting should possess specific characteristics, including tough stalks that are resistant to lodging, with grains that are hard and easily detachable.

Key words: maize, mechanical grain harvesting, organs moisture content, mechanical strength, grain broken rate