The Effect Of Nitrogen Fertilization On Oat Trait And Soil Enzyme Activity In Alpine Region

Nitrogen fertilizer plays an important role for agricultural development, which was the most widely used chemical fertilizer over the world. Nitrogen fertilizer is closely related with the improvement of human's living condition, however, it is recently found that excessive use of nitrogen fertilizer has brought much negative effects on soil and environment.The study on the relation between nitrogen fertilizer application and oat (Avena sativa L)production and environment stability in Qinghai-Tibetan Plateau was carried out on the Alpine Grassland Experimental Station of Gansu Agriculture University, which located in Tianzhu County, from 2003 to 2005. The components in garland ecosystem, including soil, grass and animal were involved in and the parameters including oat production, nutritive value of oat dry matter, soil nutrients and soil enzyme were measured. The results are shown as follows:1.Monthly dynamic of oat above-ground yield The dynamic change of oat yield in about 120 days growing period from May to September shown a S curve, which could be simulated by the following Logistic equation: y(%) = 100.8/(1+e6.628x-0.092)×100 x means days of growing; range from [0,120] y means proportion of real above-ground yield to the peak yield, range from [0,100]2. Relationship between nitrogen fertilizer and oat yield The relationship between above-ground yield and amount of nitrogen fertilizer could be expressed with the following quadratic regression equation: Y = -0.0001x2 + 0.0253x + 9.5115 (R2 = 0.6626) Y means yield, t/hm2. DM X means amount of nitrogen fertilizer, kg/hm2 The aboveground peak yield of oat and the proper applying amount of urea could be predicted by above-mentioned model as 11.1 t/hm2 and 126.5 kg/hm2 respectively.3.Effect of nitrogen fertilizer on nutritional composition and digestibility of oat Fertilization increased the content of CP (crude protein) in oat and it could be expressed by the following model: y= 0.1159x + 76.671, y was CP content of above-ground oat, %; X was amount of nitrogen fertilizer, kg/hm2.