The Effects Of Different Irrigation Patterns On Rice Yield And Quality In Cold Region And Its Crop Science Mechanism

In recently years, the rice in cold region developed very fast, with the level of production growing rapidly and now plays an important role in food production in our country. In cold region, most irrigation water comes from wells, so flooding irrigation is the widespread way. Due to the high using amount of underground water, a certain degree ecological crisis is occurring. How to reduce the amount of agricultural water using, especially to limit the underground water using, is the important issue in keeping sustainable development in cold region. Our study is focus on the water-saving irrigation issue in cold region, which set both of plot and field experiments to discuss the difference of growth performance, yield, quality and coupling effects of water and fertilizer of cold region rice under the water-limiting condition. The main results show that:1. Yields of two dry-wet alternate irrigation treatments were more than flooding irrigation treatment in Qixing. The highest yields of Kongyu131and Longjing21were9.75t/ha,9.03t/ha,which was increased by16.32%and11.92%, compared with floodingirrigation treatment. In Keyansuo, the extent of water stress was serious in the dry-wet alternate irrigation2treatment, the yield was lower than flooding irrigation treatment. The yield was not significantly affected in the dry-wet alternate irrigation1treatment. Through comprehensive both results, under the treatment of slight dry-wet alternate irrigation and soil water potential below-35kpa, yields of rice in cold region were not obviously affected, and the yields were also increased, while under the treatment of severe dry-wet alternate irrigation and soil water potential over-35kpa, yields of rice in cold region might be affected. Analysis of yield components, filled grian rate and grains per spike were not significantly affected under dry-wet alternate irrigation treatments,1000-grain weight was slightly declined, proper dry-wet alternate irrigation was in favor of increasing effective panicle number, while over the proper range of severe dry-wet alternate irrigation, effective panicle number was obviously dropping.2. Dry-wet alternate irrigation can promote the occurrence of early tiller, increase the number of stems and tillers,shorten the time of reaching the maximum number of stems and tillers and improve the average length of panicle. Compared with flooding irrigation, dry-wet alternate irrigation can increase the LAI and SPAD values of rice,thus improve the material production capacity of rice population and improve the plumpness and lodging resistance of plants.3. Compared with heading period, the breeding amount of root decreased significantly20days after heading and Konyu131droped more obvious than Longjing21. After dry-wet alternate irrigation, bleeding sap amount of root were significantly higher than flooding irrigation in heading or20days after heading.lt was also found that the bleeding sap amount of root was not significant after severe dry-wet alternate irrigation. Trough observement of root morphology, there were many white root after dry-wet alternate irrigation. There were many rot root and the colour showed dim after flooding irrigation.4. Compared with flooding irrigation, the percent of N, P, K were higher in proper dry-wet alternate irrigation. The percent of N, P, K was not significantly affected in the extent dry-wet alternate irrigation treatment. The amount of N, P, K has the same tendency with the percent of N, P, K. Compared with flooding irrigation, dry-wet alternate irrigation had more NRE, NAE, PFP. Extent dry-wet alternate irrigation could reduce Fertilizer utilization rate.5. The head rice rate was increased, but brown rice rate and milled rice rate were not significantly affected; chalky rice percentage and chalkiness were somewhat reduced, length/width was not significantly affected; the amount of protein and amylose were apparently reduce; gel consistency was apparently lengthened; Peak, Trough, and Breakdown could be increased; Pasting Temp was reduced in proper dry-wet alternate irrigation. Those showed processing quality, appearance quality, nutrition quality and RVA were improved in proper dry-wet alternate irrigation.