Study On Growth Characteristics And Yield Formation Of Mechanical Transplanting Late Rice

The yield of double seasons rice is about 57% higher than single season with the same paddy area. Developing double seasons rice production in the south of China is an effective way to increase the total rice yield. At present, the rice mechanization production level and the production efficiency in China is poor, especially the planting mechanization ratio of double cropping rice, because of the short rice planting season, poor varieties and quality for machine planting, and so on. In order to solve the problems of late transplanting rice with different sowing date, transplanting seeding age, sowing rates and transplanting depth at Hang Zhou. Select different varieties of different characteristics as the test material to study.The main research results are as follows:In order to solve the problems of late transplanting rice with different sowing date. Select two varieties of mature period characteristics as the test material to study the effect of different sowing date on growth and yield of rice. Set three sowing date as June 27 th,July 4th and July 11 th.The results showed that with deferment of sowing date, the growing period of early maturity varieties had little differences while the growing period of later maturity varieties had a obvious delay. The seedling quality, the ability to reviving turning green, the LAI and the light transmittance were decreased with a late sowing date, and the final yield was declined. The yield was decreased because of the decrease of the total number of spikelet, the seed setting rate and the effective panicles. Therefore, suitable late sowing can effectively increase the rice seedling flexibility and did not affect yield, but the delay time should not be more than a week.In order to solve the problems of late transplanting rice with different transplanting date at the lower reaches of Yangtze River. Select four varieties of different thermal and photo-response characteristics as the test material to study the effect of different transplanting date on growth and yield of rice. The results showed that growing period of thermal-response rice was delayed by long transplanting date, but less affected by the impact of photo-response rice; The yield of later thermal-response varieties with 25 d and 30 d seeding ages was significantly reduced, In contrast, the yield of early thermal-response varieties and later photo-response varieties was significantly reduced with 30 d seeding age. The optimal transplanting seeding age is 15 d of thermal-response rice, while photo-response rice is 20 d.The thermal-response rice should be selected in early maturing varieties, while the photo-response rice could be selected in late maturing varieties for high yield.In order to solve the problems of late transplanting rice with different sowing rates at the lower reaches of Yangtze River. Select two varieties of mature period characteristics as the test material to study the effect of different sowing rates on growth and yield of rice. With the increase of sowing rates, the seedling quality was declined, the seedlings were thin and poor. Reducing seeding rate could enhanced seedling quality of the individual, but the leakage of seedling transplanting was greatly increased. The tillers of single plant were increased significantly with the sowing rates increased. Appropriate high sowing rates can increase the occurrence of rice tiller, eventually improve effective panicle number. However, the tillers reduced fastest at the last stages. The characters of panicle increased, especially the number of grains per panicle were increased to make up for the effective panicle number decreased with a low sowing rates. Taken together, the Japonica rice is suitable for higher sowing rates and the suitable sowing rates was 90 g each tray. While the sowing rates of Indica rice was 70 g each tray.To explore the suitable transplanting depth of late rice under mechanically transplanting conditions, using Hyou 518 and Yongyou 2640 as test materials to study on the effect of different planting depth on the growth and yield of late rice. Designed 4 transplanting depth(1cm、3cm、5cm and 7cm) to change the planting depth. The results showed as follows: With the increase of transplanting depth, the plant individuals were vigorous, the tillers of single plant were decreased significantly. Appropriate shallow inserted can increase the occurrence of rice tiller, eventually improve effective panicle number. With the increase of transplanting depth, the leaves growth restriction and the leaf area of single plant was decreased, and the dry matter of stems and leaves was decreased. However, the characters of panicle increased, especially the number of grains per panicle were increased to make up for the effective panicle number decreased effect on yield. Therefore, the Japonica rice is suitable for shallow inserted and the suitable depth was between 1cm to 3cm.While the suitable depth of Indica rice was 3cm.