The Research On The Proper Transplanting Seedling Age In The System Of Rice Intensification And The Critical Transplanting Seedling Age Of Dry Nursery

With the Hybrid Rice Eryou498 as material, from the aspects of cultivation patterns, raising seeding densities, transplanting seeding ages, starting with the rule of dynamic changes of unit and colony foundation, and the characteristics of grain yield, the proper transplanting seeding age in the System of Rice Intensification(SRI) and the critical transplanting seeding age of dry nursery were studied. The results showed as follows:1. On the condition of the System of Rice Intensification (SRI), the influence of the seeding age on the yield, the dynamic changes of stem and tiller, leaf area index(LAI), accumulation of Photosynthate, the export and transformation percentage of the matter in stem-sheath, and SPAD value reached significant level. The yield increased firstly and then decreased with increasing of transplanting seeding age. The highest yield was 9235.88kg/hm2 appearing in the treatment of transplanting of 3 leaves and 1 bud. The yield sequence of different treatments was A2> A3>A4>A1> A5>A6>A7>A8.The transplanting seeding age was better between Al (2leaves and 1 bud) and A5 (6leaves and 1 bud), with A3 (3leaves and lbud) and A2 (4leaves and lbud) being the best, transplanting seeding age too big or too small was not good for the yield.2. On the condition of dry nursery, the seeding dry weight, root-shoot ratio(R/T), tiller number, the number of green leaves, root growth ability (number and length), root activity and the percentage content of total nitrogen of the same transplanting seeding age with different seeding density, all manifested that the treatment of 10g/m2> 15g/m2> 20g/m;On the condition of the same seeding density, tiller number, the number of green leaves, root growth ability(number and length),root activity and the percentage content of total nitrogen decreased along with the increase of transplanting seeding age, but the dry weight increased and the R/T increased firstly and then decreased while transplanting seeding age increasing. So, the quality of seedling reduced with the increase of seeding density and transplanting seeding age. The difference between various seeding density increased along with the accretion of transplanting seeding age; in the treatments of the same seeding density, the difference between various transplanting seeding age decreased with increasing transplanting seeding age; with the decrease of seeding density, the decline of seedling quality mitigated. The results of this experiment showed that, on the condition of dry nursery, to guarantee the quality of seedling, the seeding densities of old and older transplanting seeding age adapt to 15g/m2 andlOg/m2.3. On the same condition of fertilizer and water, the most important factor infecting the rice growth and development and yield was the seedling quality. The yield decreased while increased the seeding density with the same transplating seeding age; the yield declined along with the accretion of transplating seeding age with the same seeding density. And with the increase of transplanting seeding age, the more influence of seeding density to the growth period was aggrandizement. Taking the yield falling 7.5% as a standard, the yield among different treatments were measured as followed:when the seeding density were 10g/m2,15g/m2 and 20g/m2, the critical transplanting seeding age was 70 days,64 days and 58 days respectively.4. The yield characters was significantly infected by the seedling quality which has connection with transplanting seeding age and seeding density.The older the seeding age was and the higher the seeding density was,the more serious the seedling individual was restrained.So older seeding age needs low seeding density, on the contrary, smaller seeding age need high seeding density.As the increase of seeding age,the trend of yield per unit area, effective panicle number and grains per spike was downward,but the trend of grain-set rate was upward. The differences of 1000-grain weight were not affected apparently by the increase of seeding age. Yield per unit area decreased with seeding density increasing.5. According to the seasonal drought hilly region of Sichuan,on the precondition of ensuring yield, the proper seeding density was 15g/m2 and the time for transplant was within 64 days after seeding in the situation of waiting water, competing water and delayed cultivation, from the point of seeds saving, lands saving and water saving; If the seeding density was decreased, the transplanting seeding age could be controlled within 70 days.