Abstract
The ripening and drying of maize (Zea mays L.) grain are closely related to temperature. In accordance with maize grain drying characteristics, regional accumulated temperature (AT00°C) distribution is of great significance for a rational allocation of maize varieties, thus reducing grain moisture content (MC) to improve maize harvest efficiency. From 2016 to 2018, a multi-site trial was carried out in the spring maize production area of Northeastern China. In this study, under a guaranteed rate of 80% for AT0, this area was divided into 15 accumulated temperature zones (ATZs) with an interval of 100°C based on climatic data of 78 local weather stations. Then the AT0 demand of different maize varieties during different growth stages was calculated by combining experimental records with the established prediction model of MC, and then, the spatial partition for different types of maize varieties under different MCs was analyzed. The results showed that all the tested varieties could not reach physiological maturity (PM) at ATZs 13-15, hence, where maize planting is risky. With the increasing accumulated temperature demand of different types of maize varieties from planting to PM, to the MC of 25% and to the MC of 20%, the unplantable areas were gradually expanded from south to north while the region where the maize varieties could be harvested under different MCs was also moved southwardly. Additionally, at 1-2 ATZs, it is entirely possible to achieve mechanical kernel harvesting under the MC of 20%, even though the AT0 requirements of the varieties are relatively high. Conclusively, on the grounds of AT0 demand law of maize varieties and heat resource distribution in Northeastern China, the layout optimization for achieving different harvesting scenarios is conducive to providing a basis not only for selecting suitable varieties but also for promoting mechanical kernel harvesting in the spring maize production area of this region. Keywords: grain, moisture content, accumulated temperature zone, cultivars’ layout, Northeastern China DOI: 10.25165/j.ijabe.20211404.6337 Citation: Huang Z F, Hou L Y, Xue J, Wang K R, Xie R Z, Hou P, et al. Improving harvest efficiency of maize varieties via accumulated temperature in a certain planting area. Int J Agric & Biol Eng, 2021; 14(4): 175–181.
Highlights
Grain drying is affected by genotype and environment, thereinto, the temperature is an important meteorological factor affecting grain drying during crop growth and development[1,2]
The results showed that, for the AT0 required from planting to achieve moisture content (MC) of 25%, DD1331 was the highest (3525°C·d) and A6565 was the lowest (2896°C·d); for the AT0 required from planting to achieve MC of 20%, DY311 was the highest (3945°C·d) and DMY1 was the lowest (3009°C·d); for the AT0 required from physiological maturity (PM) to achieve MC of 25%, DD919 was the highest (342°C·d) and HT4 was the lowest (9°C·d); for the AT0 required from PM to achieve MC of 20%, DY311 was the highest (756°C·d) and DMY3 was the lowest (136°C·d)
The AT0 required from PM to achieve MC of 25% was 73°C·d, 151°C·d, 158°C·d, and 217°C·d for LTD, LMTD, MTD, and HTD, respectively, with an average of 160°C·d, while the AT0 required from PM to achieve MC of 20% for the four categories was 249°C·d, 378°C·d, 461°C·d, and 594°C·d, respectively, with an average of 451°C·d. 3.2 Accumulated temperature zones and the area covered by them
Summary
Grain drying is affected by genotype and environment, thereinto, the temperature is an important meteorological factor affecting grain drying during crop growth and development[1,2]. The total thermal requirement of various crops is named accumulated temperature, which is calculated as mean daily air temperature multiplied by the number of days to harvest[3]. The accumulated temperature ≥10°C is used to characterize the growth period of thermophilic crops and the number of regional heat resources[4,5]. In 1976, for the first time, a study proposed the equation y=c+dx to predict grain drying rate and MC at harvest[12]. In order to avoid the influence of environmental conditions on the drying date of grains in different ripening stages, previous studies analyzed the AT0 and MC after-silking with a more stable correlation[13,14,15], and established a regression model of the relationship between the two, so as to estimate the MC with the AT0 after-silking
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