| In order to reply the deterioration of ecological environment and the reduction of oil energy,developing and utilizing energy crops in the northwest saline region seemed particularly important.Scholars at home and abroad paid more attention to the introduction ecological adaptability, cultivation techniques and biomass yield of energy crops switchgrass. However, the scholars studied less on its formation and regulation of biomass, especially the ecological adaptability, the biomass formation law and the high yield fertilization technology and mechanism of the introduction of switchgrass to saline alkali soil are not clear now. Therefore,the research method of orthogonal test using the pot of different water and different fertilizer salt treatment on switchgrass yield, growth indexes, physiological characteristics, effects of nitrogen phosphorus and potassium ion content and the response characteristics of switchgrass,proven water salt coupling effect,suitable for water fertilizer salt management mode, to provide theoretical and technical support for saline to switchgrass cultivation test.The main conclusions are as follows:(1)There were obvious coupling effect of water fertilizer salt on the growth of swicthgrass plants,soil water content and soil salinity affects switchgrass plant height, tillers, leaf area, leaf number and main factors of dry matter yield,but nitrogen could reduce water salt stress adversely affect length and yield of switchgrass to a certain extent. Test under the condition of switchgrass in soil salt was 0.16%,the soil moisture content was 80%-85%,nitrogen fertilizer was 60kg/hm2-120kg/hm2 could obtain the highest biomass yield.(2)The soil moisture content and soil salinity was the main influencing factors of MDA and soluble sugar content, which increased significantly under the conditions, effects of Nitrogen Application on MDA and soluble sugar content was not significant, but the effect of water and fertilizer coupling effects on salt MDA and soluble sugar content of soil significantly.Water,amount of nitrogen fertilizer and water fertilizer salt coupling on switchgrass SOD influence enzyme activity CAT protection significantly, but no significant effects of soil salinity, indicated that fertilization could alleviate salt stress, enhance the resistance of switchgrass.(3)Water and fertilizer coupling salt had significant effects on the photosynthesis on switchgrass,water salt stress could damage the function of chloroplast, signification rate of millet switchgrass, net photosynthetic rate, stomatal conductance. In different salinity conditions, through appropriate water and fertilizer control(soil water content was 80%?85%,nitrogen fertilizer 240kg/hm2) could reduce the effect of salt stress on Photosynthesis of switchgrass, maintained higher photosynthetic efficiency.(4)The amount of nitrogen fertilizer was the main factor affecting the nitrogen content of switchgrass plants, followed by soil moisture and soil salinity, three factors had significant effects on plant nitrogen content of switchgrass. Under high salt conditions(soil salinity was 0.45%), high fat(240kg/hm2) and water(soil moisture content is 80%?85%)to obtain the highest plant nitrogen content. Soil moisture was the main factor affecting the phosphorus potassium content of switchgrass,followed by soil salinity. Water under severe salt stress conditions, application of nitrogen fertilizer would reduce the absorption of phosphorus and potassium in switchgrass.(5)Water salt coupling had a significant influence on Cation absorption. With water absorption and salt stress, switchgrass plant Na+, K+ content increased. In general, switchgrass plants cation content of soil moisture was more sensitive to soil salinity and the nitrogen level had a certain response,the ion content of water and fertilizer regulation salinity conditions of switchgrass. |
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