Studies On The Effects Of Cultivation Patterns To Yield Formation And The Regional Adaptability Of The Patterns In Double Croppillg Rice

In order to explore the yield formation characteristics of double cropping rice under different cultivation patterns and the regional adaptability of cultivation patterns, five treatments including nitrogen blank (M1), farmer’s practice(M2), high yield and efficient cultivation model (M3), super-high yield cultivation model (M4), super-high yield and efficient cultivation model (M5) were designed and field experiments of double rice including yield trial in Ningxiang county and multi-location trials in Ningxiang county(NX), Lilin city(LL) and Qiyang county(Q Y) of Hunan province were conducted in2011. Grain yield and its components, source-sink relation, dry matter accumulation, plant height, and growth rate, etc. were measured in the research. The major results were showed as follows:(1) The characteristics of yield and yield formation of double cropping rice under different cultivation patterns. There was a significant difference in yield of double cropping rice. The yield of cultivation patterns in early and late rice was characterized with the gradient variation of super-high yield cultivation model (M4)>super-high yield and efficient cultivation model (M5)>high yield and efficient cultivation model (M3)> farmer’s practice (M2)>nitrogen blank (M1).Compared with farmer’s practice, the yield of the high yield and efficient cultivation model, super-high yield cultivation model, super-high yield and efficient cultivation model in early rice increased by4.9%,10.1%,6.8%, and in late rice by12.2%,19.2%,17.5%, all the amplitude of yield reaching a significant level.(2) Yield-increasing mechanism under different cultivation patterns in double cropping rice. Analyzing from yield structure, the main reason of yield-increasing for high yield and efficient cultivation model, super-high yield cultivation model, super-high yield and efficient cultivation model was the significant increasing of effective panicles per unit area (average of early rice and later rice respectively increase19.4%、46.0%、34.2%) which led to the significant increasing of total spikelets per unit area and thus sink capacity expanded significantly. Analyzing from the dry matter formation, compared with f farmer’s practice, the reasons of yield-increasing of M3, M4, M5were that their SPAD values still remained high in the middle growth, which resulted in the dry matter accumulation from booting maintained a certain advantages. At the same time, the superiority in plant height, leaf-stem ratio, change of growth rate was the premise of the dry matter production advantages.(3) Different ecological areas adaptability of cultivation patterns. The changes of yield formation at Lilin and Qiyang under different cultivation patterns were similar with Ningxiang. The yield of early and late rice of cultivation patterns was characterized with the gradient variation of super-high yield cultivation model> super-high yield and efficient cultivation model>high yield and efficient cultivation model>farmer’s practice> nitrogen blank. The main reason of yield-increasing for cultivation patterns (M3, M4, M5) was the increasing of effective panicles per unit area and total spikelets per unit area.(4) Yield-increasing effect of high yield and efficient cultivation model, super-high yield cultivation model, super-high yield and efficient cultivation model at different ecological areas showed differences. Compared with farmer’s practice, the yield-increasing effect of high yield and efficient cultivation model on early rice was Lilin> Qiyang> Ningxiang, while late rice was Lilin> Ningxiang> Qiyang. But the yield-increasing effect of super-high yield cultivation model and super-high yield and efficient cultivation model on early and late rice were Lilin> Qiyang> Ningxiang.Only from the view of high yield production, compared with farmer’s practice(M2), the integrated cultivation models (M3, M4, M5) in this research achieved significant yield increasing effect in tested different ecological areas, showed a common law of yield-increasing as M4>M5>M3,and had better regional adaptability.