Effects Of Different Seedling Substrates And Mechanical Transplanting On Growth And Yield Of Rice

Rice production mechanization is the main development direction of rice cultivation.In the rice mechanical production of China,the mechanical transplanting is the weakest link.The transplanting shock and missing hills cause a different growth and development of mechanical transplanting in the field,the difference of grain yield between this two system is uncertainty. Seedling quality affect the transplanting quality and yield potential,most researches are focus on seedling age, seeding rate and seedling raising method,and only a few research on seedling substrates and plant growth regulators.To solve these problem,we conduct the difference of rice yield between mechanical and manual transplanted,the difference of growth and development between different seedling substrates and the effect of different growth regulators on mechanized transplanting seedling quality experiment to understand the effects of different seedling substrates and mechanical transplanting on growth and yield of rice,and provide a technical support to the mechanical transplanting.The main results were as follows:1. The research of growth and development between different seedling substrates shows that the seedling quality and grain yield of Jinmantian substrate seedling are significantly greater than the nutrient soil seedling.The yield of nutrient soil seedling raise in the disc transplant by machine is8.38t hm-2,and its manual transplant yield is8.21t hm-2,no difference between these two yields.Through growth analysis we find that the the maximum tiller number and panical number of mechanical transplanted are bigger than manual transplanted,but the leaf area index and aboveground dry weight are lower than manual transplanted.2. The research of different growth regulators on mechanized transplanting seedling quality shows that naphthalene acetic acid(NAA) and6-benzyl adenine(6-BA) soaking seed can increase the leaf number,root number,maximum root length and plant dry weight.The high concentration2,4-dichlorophenoxyacetic acid(2,4-D) can make the youngh seedling death.The fitting concentration range of NAA soaking seed is0.005-0.01mg/L,and the fitting range of6-BA is0.05-0.5mg/L.3. The research of cavity and seedlings per hill of mechanical transplanted shows that the cavity rate is6.1%,the evenness quality-rate is60.2%and the planting quality-rate is70.7%.The cavity rate less than10%will not be decreased for the compensation effect can remove the negative effect of missing hills.4. The yield difference of mechanical and manual transplanting in Xiaogan,Honghu,Qichun and Wuxue show that the yield of mechanical transplanted is1.07t hm-2(11.7%)lower than manual transplanted.The reasons of the lower yield are the biomass, the spikelets per panicle and grain filling percentage are all lower than manual transplanted.The dry matter translocated from the leaf and stem to the panicle during ripening is479g m-2,the newly assimilated dry matter during ripening is358g m-2,and the relevant of manual transplanted are545g m-2and394g m-2,to improve the yield of mechanical transplanting, it should increase the dry matter translocated after flowering,and increase the spikelets per panicle and grain filling percentage and insure the panicle number at the same time. The research of cost analysis shows that the cost of mechanical transplanted is1050yuan hm-2lower than manual transplanted.We conclude that the seedling quality effects the yield of mechanical transplanting, the seedling quality and grain yield of Jinmantian substrate seedling are significantly greater than the nutrient soil seedling.There is no difference of yield between mechanical and manual transplanting when transplanted the same seedlings.Now the yield of mechanical transplanting is less than manual transplanting for its lower biomass.To improve the yield of mechanical transplanting,it should increase the dry matter translocated after flowering and increase the spikelets per panicle and grain filling percentage and insure the panicle number at the same time.