Effects Of Irrigation On Physiological Ecology And Water Use Efficiency Of Main Rice Growing Period

Rice is the most water-consuming food crop and is affected by water resources and irrigation conditions. To study the difference of water requirement and the effect of irrigation on the physiological characteristics of rice, the temperature and humidity of paddy field and yield of rice, can provide the theoretical basis for improving the water use efficiency of rice effectively while ensuring the maximum yield. The experiments were carried out at the Agricultural Meteorological Experiment Station of Nanjing University of Information Science and Technology,and the two rice varieties of Liangyou 6326 were sowed twice. The test was carried out in two groups. The main results of the study are as follows:(1) The water requirement of rice was affected by the depth of irrigation, and the regularity of heading and flowering stage was similar. The water requirement of 0-1 cm irrigation were relatively low, and there was no significant difference in water demand between 4-6cm irrigation and 8-10cm irrigation. At the same height as the depth of irrigation increases, the temperature above the rice will be reduced accordingly. The relative humidity of 8-10cm deep water treatment is the largest,and the influence of paddy water layer on the relative humidity of the above is weakened with the increase of observation height.(2) The effect of irrigation depth on the growth and physiological characteristics of rice was different, and the photosynthetic rate, transpiration rate and stomatal conductance were increased with the increase of irrigation depth. The plant height and leaf area index of 0-1 cm irrigation were affected by water limitation,and the photosynthesis of field was decreased. The effect of stomatal conductance on the photosynthetic rate was significantly increased with the increase of irrigation depth, and the photosynthetic rate of photosynthetic rate increased with the increase of irrigation depth. And the effect on the rate of transpiration was slightly reduced.(3) The effect of irrigation on the water use efficiency of rice was 8-10cm, and the 0-1 cm irrigation was the lowest, while the water use efficiency of 4-6cm and 8-10cm irrigation was very small. Leaf water use efficiency and photosynthetic rate were positively correlated. The transpiration rate increased with the increase of transpiration rate before 8mmol·m-2·g-1, and then decreased with the increase of transpiration. The water use efficiency increased with the increase of yield, and the water requirement of rice was more than 8200 m3/hm2, and the water use efficiency was significantly improved when the water demand was more than 8200 m3/Dm2.Increase and decrease. From the aspects of water saving and economic yield,it is necessary to take 4-6cm deep irrigation in the heading and flowering stages of rice,which can ensure the high efficiency of water use efficiency while maximizing the yield.