有些农户,由于当年收获的种子生芽或不纯净等原因,把存放多年的纯净种子播下,结果,不发芽或虽发芽,但植珠瘦弱,产量很低。其主要原因是种子收获后保管不当,使其失去生活力或衰老造成的。种子也有寿命,在一定条件下,能保持90%发芽率的期限,作为农业种子的寿命。种子寿命的长短,一方面决定于作物本身的遗传性,如稻、麦、玉米等禾谷类种子 Some peasants sow the pure seeds stored for many years because of the germination or impureness of the seeds harvested at that year. As a result, they did not germinate or sprouted but the pearl plants became thin and the yield was very low. The main reason is the improper storage of seeds after harvest, resulting in loss of vitality or aging. Seed also has a life expectancy, under certain conditions, can maintain the 90% germination rate of the deadline, as the life of agricultural seeds. The length of seed life, on the one hand, depends on the heredity of the crop itself, such as rice, wheat, corn and other cereal seeds