关键词: 污染物, 污染物

Abstract: Researches on mechanical transplanting technology for double cropping early season rice play an important role in mechanization culture of rice production. Seedling raising methods and transplanting density were the key points in mechanical transplanting technology for early season rice. In the present study, different treatments of sowing rate, seedbed types and transplanting density were designed to investigate the influence on seedling growth, seedling quality and machine- transplanted quality of early season rice using variety‘Zhongzao 9’. It was shown that, for sowing rate, 110 g per disc could raise strong seedlings with higher emergence rate, adult seeding rate and ratio of seedling weight to height, and high quality seedlings of mechanical transplanting were obtained. Compared with seedlings raised by various seedbed types,“pot mixture”or“pot mixture plus yellow soil”, these two kinds of seedbed types would develop healthy and strong seedling plants, wide stem and high quality for machine transplanting. After transplanting in growing field, seedlings revived fast, and develop higher effective tiller numbers per area, resulted in high output at last. The experiment of transplanting density was conducted; it indicated that two designs of distance of row: line 30cm×14cm or 24cm×17cm, transplanting density 244500 holes/hm² and 238500 holes/hm² were in favor for rice growth and developments, including large panicles, optimized plant population and higher yields.