Study On The Different Seedling Ages And Densities Of SRI

The rule of rice physiological characteristics, population development and representation of yield were studied by different transplanting leaf age, different density and different planting model with hybrid rice Xieyou527 and Gangyou527 in 2002 and 2003, under SRI (system of rice intensification) and TC (traditional cultivation) conditions. The results are as follow.(1) The results shows that SRI is beneficial to tillering potential of individuals, increases the ratio of productive tiller and effective panicle number, has sturdy individuals, improves the character of panicle, increases 1000 grain weight and much significant increases grain yield.(2) In SRI condition, transplant of different leaf age (from 2 to 5 leaf age) seedlings has very small effect on grain yield. Therefore, in practice, in order to benefit quality of seedling, adapt to joining rice stubble field of the double cropping system, avoid influence of low temperature after transplanting seedling too early on regreen-survival and plant growth, we may transplant from 4 to 5 leave seedling with tiller to get possible better results.(3) In this experiment conditions, the suitable planting density of SRI is 9*104cave/hm2to 13.5*104cave/hnr and its grain yield is highest. Planting model of triangular planting three seedlings per stagger hill has higher grain yield than that of one seedling per hill. So high yield under SRI conditions must need suitable planting density and model, but the best planting density and model still need further study.(4) SRI has larger leaf area of individuals than TC. The leaf area of top 3 leave is smaller than TC at heading stage, but it lessens slowly after heading, maintains higher photosynthetic potential and improves photosynthesis produce ability of population.(5) In similar ecological conditions, the quality' of individuals has significantly different because of different density, i.e. Low density cultivation is obviously higher than high density' cultivation in photosynthetic rate, stomatal conductance, transpiration rate, those have no different change trend under TC. At heading stage and after heading, the biomass of SRI is significantly higher than that of TC because SRI has higher chlorophyll content, slower senescence of leave, stronger photosynthesis produce capacity and a large amount of matter accumulation.(6) The results indicate that SRI has higher chlorophyll and lower malondialdehyde (MDA) content in top 3 leave as well as chlorophyll decompose slow and slow rate of leave senescence. SRI can effective improve quality of population, especially individual quality in late stage of population, so, it is advantage conditions of increasing gain yield and improving quality of rice.The results show, in SRI conditions, transplanting different leafage seedlings have small effect on grain yield, therefore, we may transplant 4-5 leave seedlings with tiller in practice; but different density has marked effect on grain yield, the experiments indicated that 9*104cave/hm2 to 13.5*104cave/hm2 is reasonable density, triangular planting three seedling per stagger hill is better model of cultivations.