Experimental And Mathematical Model Of Rice Canopy Structure And Dry Matter Production Under Controlled Irrigation

Rice tiller dynamic development, plant height, Canopy Leaf Area Index, Mean Foliage Inclination Angle, Transmission Coefficient for Diffuse Radiation, Transmission Coefficient for Solar beam Radiation Penetration, Extinction Coefficient and Leaf Distribution under controlled irrigation and traditional irrigation were analyzed. The effects of canopy structure on light interception and transmission characteristic were studied according to the data of field irrigation experiment. Also, Rice dry matter accumulation and partition of two different water conditions were compared through the entire period of the experiment. Moreover, a Logistic model for simulating tiller development was developed, a hyperbolic model and Chapman-Richards model were developed to simulated the rice dry matter accumulation. The result indicated.1. Rational water control have a obvious effect on rice colony characteristics and canopy structure, which could ameliorate light transmission condition and acquire more light interception. Finally the rice under controlled irrigation achieved high yield on the condition of saving water.2. The effects of canopy structure on light interception and transmission characteristic are prominent. The Transmission Coefficient for Diffuse Radiation and Transmission Coefficient for Solar beam Radiation Penetration are reduce when Canopy Leaf Area Index rise, and the Extinction Coefficient decrease when Mean Foliage Inclination Angle increase.3. Adjust water layer and soil moisture in paddy fields has great influence on plant height and dry matter accumulation. The plant height and dry matter accumulation were reduced under low soil moisture. Once the soil moisture of paddy fields was improved, rice growth speed was rebound and higher than that of CK.4. The Logistic model is suitable to simulating the rice growth process. Of the four models tested, the Logistic model gave the closer fit and more accurate estimate of the ground dry matter accumulation of rice. The Mitscherlich could not estimate the rice growth process.5. In the late of jointing and booting stage rice has highest dry matter productivity. The 26 to 60 days after transplanting is rice significant growth period, in whichdry matter accumulation is 60% of the whole stage. So it is very important to strengthen paddy field management and enhance academic research.6. The rice yield of the controlled irrigation is almost equal to that of the CK, but the controlled irrigation reduces the amount of irrigation and increase water use efficiency. Rice irrigation of the controlled irrigation is 2774.0 m3·hm-2, which reduced by 40.4% than that of the CK. Also, the water use efficiency and irrigation water use efficiency of the controlled irrigation are improved by 37%and 68.5% than that of the CK.