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北方农村,秋收后留作种用的玉米,多是不脱粒、带穗过冬;南方则大都脱粒贮藏,这是为什么?要回答这个问题,首先应弄清楚空气温度与玉米果穗含水量的关系。实验证明:当空气的相对湿度为75%时,整个玉米果穗的平衡水分为14%左右。若空气湿度低于75%时,穗轴比籽粒含有的水分少,籽粒中的水分便不断地为穗轴所吸收,这就有利于籽粒的干燥;若空气湿度高于75%时,穗轴比籽粒含有的水分多,穗轴内的水分便不断地转运给籽粒,因而也就不利于籽粒的干燥。黄河流域以北各地,玉米收获以后到翌年春季,空气相对湿度都在75%以下,玉米经过晾干在自然条件下带穗保管过冬,含水量便可以降低到安全水分以下,完全能够避免发生冻害,保持良好的发芽能力。同时由于采用果穗贮藏的籽粒其顶部有角质层和完整的果皮掩盖,使胚部隐蔽,霉菌寄生较少,在色泽、食味和完整性方面也都比脱粒贮藏的优良。在长汇以南,玉米播种的季节长,贮藏的时期随之延长,并且气温高、湿度大。如四川省的成都、重庆和湖北省的恩施县,每年都有9个月空气相对湿度在80%以上,尤其是在高温多雨的夏季,极易为霉菌的寄生而发热霉烂,因此留种用的玉米收获以后,必须及时晾干或烘干然后脱粒贮藏。由于玉米胚部含有较多的蛋白质和脂肪,营养丰富,呼吸强度大,带菌较多,所以霉变常由胚部开始。脱粒贮藏时每100斤籽粒可拌入5斤石灰,放入木桶或谷囤内密封,既可保持干燥,还有一定的防治病虫的效果。
Northern rural areas, after harvest as corn for planting, mostly do not threshing, with wintering winter; most southern threshing storage, which is why? To answer this question, we should first find out the relationship between air temperature and corn ear water content. Experiments show that: when the air relative humidity of 75%, the balance of corn ear water is about 14%. If the air humidity is lower than 75%, the cob contains less moisture than the grain, and the water in the grain is continuously absorbed by the cob, which is beneficial to the drying of the grain. If the air humidity is higher than 75%, the cob More than the moisture contained in the grain, the moisture in the cob is continuously transported to the grain, which in turn is not conducive to the drying of the grain. After harvesting the corn to the following spring, the relative humidity of the air is below 75%. After the corn is dried under natural conditions and kept in the ear for the winter, the water content can be reduced below the safe water, which can completely avoid the frost damage , Maintain good germination ability. At the same time, due to the use of ears stored in the top of the stratum corneum and the integrity of the pericarp cover, so that the embryo hidden, less mold parasitic, color, taste and integrity than the threshing storage excellent. In the south of Changhui, the season of corn sowing is prolonged, the period of storage is prolonged, and the temperature is high and the humidity is high. For example, in Chengdu, Chongqing and Enshi in Hubei Province, the air relative humidity is over 80% every year for 9 months. Especially in the hot and rainy summer, it is extremely easy to mold and mold and cause fever and mildew. Therefore, After the harvest of corn, you must promptly dried or dried and then threshed storage. As corn embryo contains more protein and fat, nutrient-rich, respiratory intensity, more bacteria, so mold often start from the embryo. Threshing storage per 100 kg of grain can be mixed with 5 kg of lime, into the barrel or valley store sealed, either to keep dry, there are certain effects of pest control.