Effect Of Different Irrigation Methods On Yield And Quality Of Rice Under Different Soil Types

The experiment was carried out in Yangzhou University from 2015 to 2017 in the laboratory of crop cultivation physiology,and the conventional japonica rice Nanjing 9108 was used as material.The experiment uses two factors random design,set three kinds of soil,three kinds of irrigation methods:(1)Conventional Irrigation(CK),long-term 3-5cm shallow water irrigation,water cut off the week before harvest.(2)Light water-saving irrigation(-15kPa),irrigation to the water depth of 3-5cm stop irrigation,and natural fall to the soil water potential of-15 kPa and then irrigation 3-5cm,so the cycle,water cut off the week before harvest.(3)Severe water-saving irrigation(-25kPa),irrigation to the water depth of 3-5cm stop irrigation,and natural fall to the soil water potential of-25kPa and then irrigation 3-5cm,so the cycle,water cut off the week before harvest.The effects of different irrigation modes on the yield formation,root morphology and quality of rice under different soil types were studied in order to provide theoretical and practical basis for high yield and water saving irrigation of rice under different soil types.The main results are as follows:1.Under the three irrigation methods,the yield of-15kPa was significantly higher than that of conventional irrigation and severe water-saving irrigation,with an average increase of 5.7%and 5.3%.The three soils had significant effects on yield under different irrigation methods.The yield of clay and loam was the highest under light water saving irrigation,and significantly higher than that of the other two treatments.The yield of sand in conventional irrigation was the highest,and was significantly higher than that of mild and severe water-saving irrigation.Compared with conventional irrigation,clay and loam increased by 11.5%and 13.6%respectively in the light water-saving irrigation,while severe water-saving irrigation increased 5.6%and 6.9%;Further analysis showed that the light water-saving increased 5.9%and 6.7%compared with the sever water-saving irrigation.The yield of sandy soil was descend 5.9%and 10.3%compared with that of conventional irrigation in light water-saving and sever water-saving.The variation range of rice yield under different soil types varied with different irrigation methods,showing that loam soil was 2.0%-3.9%higher and 4.4%-25.6%higher than clay and sand respectively.The irrigation water consumption of three kinds of soil under light water-saving irrigation was significantly lower than that of conventional irrigation,and the water use efficiency was significantly higher than conventional irrigation;The tiller number of rice in the whole growth period showed conventional irrigation>light water-saving irrigation>sever water-saving irrigation,and the rate of panicle formation of clay loam soil was higher than that of conventional irrigation under light water-saving irrigation,while that of sandy soil was the highest under conventional irrigation;The leaf area index and dry matter accumulation in heading stage and mature stage were the highest in light water saving irrigation,lowest in conventional irrigation,and highest in sandy soil,while the lowest in sever water-saving irrigation.1.The photosynthetic potential of three soils in the different irrigation modes from jointing to heading stage had no significant change;Clay and loam showed photosynthetic potential of light water-saving irrigation from heading to maturity stage,and the population growth rate was significantly higher than that of conventional irrigation.The net assimilation rates of clay and loam from jointing stage to heading stage and heading stage to maturity stage were significantly higher than those of conventional irrigation,while the sandy soil showed the highest under conventional irrigation.The photosynthetic rate and SPAD value of clay loam soil were the highest in light water-saving irrigation,lowest in conventional irrigation,sandy soil in conventional irrigation,and the lowest in sever water-saving irrigation.The transpiration rate and stomatal conductance of the three soils under different irrigation modes showed that the conventional irrigation was higher than the water-saving irrigation.3.The root dry weight,root-shoot ratio and root length of three soils did not change significantly at jointing stage,at heading stage and mature stage,clay and loam were the highest in light water-saving irrigation,and lowest in conventional irrigation,sand showed conventional irrigation was higher than light water-saving irrigation;The three soils had no significant effect on root diameter under different irrigation methods;at the jointing stage,the root oxidative and traumatic fluxes were lower than those of conventional irrigation,heading and mature stages,and clay and loam in light water-saving irrigation were higher than conventional irrigation,Sand is manifested as conventional irrigation is higher than water-saving irrigation.4.Clay and loam both increased the brown rice rate,the milled rice rate and the milled rice rate significantly in the light water-saving irrigation,reduce the chalky rate,chalky size,chalkiness.Sandy soil increased rice brown rice rate,milled rice rate,head rice rate,reduced chalkiness rate,chalkiness size and chalkiness degree,improved appearance quality and nutritional quality of rice under conventional irrigation.Light and severe water-saving irrigation significantly increased the peak viscosity and disintegration value of paddy soil under clay and loamy soil,and reduced the decrease value.Under the conventional irrigation,the peak viscosity and disintegration value of sandy soil were the highest,and the minimum value of reduction was the lowest.