Dissertation
Dissertation > Agricultural Sciences > Crop > Fodder crops,pasture > Perennial legume > Other

Effect of Regulation and Control of Water and Nitrogen on Seed Yield of Alfalfa

Author LiLi
Tutor ShengJianDong
School Xinjiang Agricultural University
Course Soil
Keywords Alfalfa Seed yield Regulation and control of water and fertilize
CLC S541.9
Type Master's thesis
Year 2012
Downloads 56
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Alfalfa, as the most widely distributed and planted forage in China, faces the serious problems of low yield, low water and fertilizer utilization rate, and so on. This study deals with the effect of different combination of water and nitrogen on alfalfa seed growth, yield and water and fertilizer use efficiency and the effect on farmland environment. The results are as fellow:(1).Effect of water and nitrogen coupling on alfalfa growth and seed production: applying nitrogen and water can both increase alfalfa yield. But with the increasing of nitrogen and water, alfalfa seed yield enhances first and then gradually decreases.When applied nitrogen150kg/hm, and water1000m/hm, dry matter accumulation, total nitrogen accumulation and seed yield are14201kg/hm、260kg/hm2、734kg/hm2respectively.(2).Effect of water and nitrogen coupling on alfalfa water and nitrogen use efficiency: With increase in irrigation, water use efficiency decreases, When the irrigation is500m3/hm2, water use efficiency reaches the highest level, and its value is0.72kg/m3. With the increase in N fertilizer, water use efficiency enhances first and then becomes lower. When the nitrogen is100kg/hm2, nitrogen partial factor productivity is4.67kg/kg. It is the highest among treatments. Take all factors of water use efficiency and nitrogen partial factor productivity into consideration, water and nitrogen coupling of150kg/hm2and1000m3/hm2respectively is optimal allocation and yield increasing allocation, the water use efficiency and nitrogen partial factor productivity is0.73kg/m3,4.89kg/kg respectively.(3).Effect of water and nitrogen coupling on the farmland environmental benefits of alfalfa seed:Effect on soil moisture:The most appropriate irrigation amount is1000ms/hm2.Bud stage to flowering is the best period for irrigating. Irrigation and nitrogen fertilization mainly affect the soil water content within the0-40cm soil layer.The soil nitrate content increases with increasing amount of nitrogen. Increase in irrigation volume reduces the content of the soil surface nitrate. Deepness of peak value of nitrate content increases with the increase of irrigation volume. Nitrogen application greater than150kg/hm2causes the accumulation of nitrate in soil profiles.40-60cm of soil profiles is the accumulation levels of nitrate nitrogen.In short, this research preliminarily confirms the critical and high use efficiency period of the coupling of water and nutrient for alfalfa seed production, and provides foundation for alfalfa seed efficient production and friendly environment.

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