Effects Of Sowing Date, Sowing Rate And Transplanting Density On The Yield Formation And Nitrogen Absorption Of Mechanical Transplanting Rice Ning Jing 1

The experiment was carried out on Shuang Xu farm of Shengao Town of Jiangyan County in Jiangsu Province during the year 2006-2007.The experiment set 3 sowing dates ( May 16, May 21 and May 26), 3 sowing rates (80g/plate, 100g/plate and 120g/plate) and 3 transplanting density (15,000 hole/mu, 17,000 holes/mu and 19,000 hole/mu) and studied their effects on the growth,yield formation and nitrogen absorption and use of the mechanical transplanting rice Ning Jing 1 .The result showed as follows:(1)the rice seedling quality affect the yield, The result showed that with the prolonging of sowing date,the seeding height,the seedling shoot width increased, the seedling of 30 days seedling age had the highest value.while the field root power,the seedling bearing rate,the number of seedlings per square decreased. The dry matter weight of all the treatments decreased 25 days after sowing .the seedling quality became bad quickly.with the growing sowing rate, the seedling height and the number of seedlings per square increased, while the field root power, dry matter weight on the floor, the seedling shoot width and the seedling bearing rate decreased,the rice quality decreased.(2) the yield showed decline trends with the aheading of the sowing date and the prolonging of seedling age .During the seedling age 20 to 30 days,the yield drops 17kg/mu averagelly with 1 day increases.during the sowing rate 80g/plate to 120g/plate. the yield declined 14.7kg/mu averagelly with 10 g/plate increases . during the transplanting density15,000 hole/mu to19,000 hole/mu. the yield increases 9.2kg/mu averagelly with 1,000 hole/mu increases.the treatment 20days seedling date, 80g/plate sowing rate and transplanting density 19,000 hole/mu got the highest yield. Along with the prolonging of seedling age and the increasing of sowing rate ,the seed setting rate and 1000-grain weight increased,the effective panicles ,grains per panicle and yield decreased. Along with the increasing of transplanting density,the effective panicles, the total glumous flowers and yield increased greatly,while the seed setting rate and 1000-grain weight decreased.(3) the seedling age and the sowing rate had the influence on the seedling quality and the growth of later growing period. along with aheading of the sowing date and prolonging of the seedling age and the increasing the sowing rate, the speed of the leavies turns green slowed,the tillers dropt, the period of maxium of the tillers and stems postponed and finially reduced the effective ear rate and effective tillers and stems. Along with the increasing of transplanting density, the basic seedling increases, the number of final effective ear also showed a increasing tendency.(4) the LAI of all the growing period showed the treatment of 20 days seedling age (sowed on May 26) > (sowed on May 21) > (sowed on May 16); the 80g/plate sowing rate >100 the g/plate >120 g/plate; 19,000 hole/mu transplants density > 17,000 hole/ mu > 15,000 hole/ mu.(5) the dry matter accumulation proportion of all the period of different sowing date ,sowing rate and transplanting density had no significant difference . the dry matter accumulation proportion of the jointing to the earing period had the highest proportion, the earing to the maturity followed,the dry matter accumulation before the jointing period was the lowest.the difference of HI was not big.the total dry matter accumulation decreased along with the aheading of sowing date and the prolonging of seedling age.while increased along with the decreasing of sowing rate and the increasing of transplanting density.(6) the Nitrogen accumulation and total absorption amount of all the growing period showed the treatment of sowed on May 26> sowed on May 21> sowed on May 16; the 80g/plate sowing rate >100 the g/plate >120 g/plate; 19,000 hole/mu transplants density > 17,000 hole/ mu > 15,000 hole/ mu.