Study On The Saving-irrigation And Increasing Irrigated Water Temperature In Well Irrigation Area In Sanjiang Plain Through Experiment

Irrigating with very cold water in well irrigation rice area of SanJiang plain can lead to decrease temperature in the field, affect normal development of the rice, and reduce the production of the rice. In order to resolve this problem, the paper mainly studied that the methods of increasing water temperature, such as sunning water pool and channel, and discussed how the irrigation affected water and soil temperature in the field under the saving water irrigation condition and the production of well irrigation rice. At last, we put forward to the best method for resolving the low temperature and cold damage in SanJiang plain. The experimental results are as follows:(1) The effect factors of increasing water temperature through sunning water in sunning water pool and channelSunning water pool and channel consideration prior in the technology of increasing water temperature development, then it is the turn of other technology of increasing water temperature in well irrigation rice area in SanJiang plain. The main factors of increasing water temperature of sunning water pool are air temperature, the area and depth of sunning water pool. The main influence factors of increasing water temperature of the channel are air temperature, the length, width-depth ratio and flow of channel.(2) Soil water potential criteria for water-saving and high-yield in paddy riceAccording to the control principle of soil water for water-saving and high-yield in paddy rice, and experimental experience in three or four years, soil water potential criteria in the paper is that saturated soil moisture in the turning green period, making the smallest soil water tension, soil water potential becoming zero. Soil water needs light control and middle control in the early tillering stage and middle tillering stage, increasing soil day and night temperature difference and soil heat flux, and increasing soil oxidation and reduction potential. Soil water is controlled heavily in the tillering late stage for controlling nitrogen absorption, increasing the carbon and nitrogen ratio of leaf, promoting rice transformation from nutritional growth to reproductive growth. Soil water is controlled lightly in the booting and heading stage. Soil water needs middle control in the milky stage and drainages of the rice field in the yellow ripe stage.(3) Water and soil temperature are affected by irrigation under the saving water irrigation conditionUnder the saving water irrigation condition, sunning water on the field can increase water temperature faster than before. Through sunning water an hour, the water temperature increased 7～8℃, and sunning water tow hours, the water temperature increase to more than 20℃. The irrigation water temperature satisfies the need of rice. There is no water layer in the whole growing period under the controlled irrigation, so soil moisture is low and the soil temperature is easy to increase. The soil temperature of controlled irrigation is 1℃higher than the soil temperature of intermitted irrigation. Controlled irrigation is easy to obtain higher production.(4) Saving water and increasing production potential under the saving water irrigation condition Under the saving water irrigation condition, the production of well irrigation rice is equal to the production of surface water irrigation rice in 2006. In 2007, the production of well irrigation rice is 6% higher than the production of surface water irrigation, because water controlled well. Through developing saving water irrigation, well irrigation rice can defend the low temperature and cold damage, and obtain higher production like the production of surface water irrigation. The production of controlled irrigation is 7%～8% higher than the production of intermitted irrigation, but irrigation water use reduces 10.4%.In short, Sunning water pool and channel consideration prior in the technology of increasing water temperature development, then it is the turn of other technology of increasing water temperature in well irrigation rice area in SanJiang plain. We should pay attention to comprehensive application of irrigation management and the method of saving water irrigation. Saving water irrigation unifies sunning-water, water delivery, irrigating, and saving-water, irrigates properly, improves thermal environment and humidity environment in the field, and adjusts growth of the rice. Saving water irrigation can save water, increase temperature in the field, and increase the production of rice, which is the best method to defend cold damage in well irrigation rice area in SanJiang plain.