Coupling Of Water And Fertilizer Effects On Productivity And Quality Of Aohan Alfalfa

The objective of this study was to show the effects of ratio N,P and water on growing characteristics,hay yields,nutrients and soil fertility of alfalfa in two years, adopted complete split-plot experimental design. The main conclusions as follows:1. The relation of yield and yield components :When N,P fertilizer and irrigation increased dosage, plant height was higher and the number of branch first increased and then decreased,but the number of branch has no significant difference in two level of water. The diameter of main stem increase insignificantly.2. The highest treatment of total hey yield was: 300 kg/hm²(N)+450 kg/hm²(P)+ 2300m³/hm²(W)(41335 kg/hm²).In the interaction treatment of N,P,W three factors ,the highest treatment of hey yield was: 300 kg/hm²(N)+450 kg/hm²(P)+ 2300m³/hm²(W); In the interaction treatment of N and W two factors, the highest treatment of hey yield was: 300 kg/hm² (N)+1150m³/hm²(W); In the interaction treatment of P and W two factors,the highest treatment of hey yield was: 450 kg/hm²(P)+2300m³/hm²(W); N,P,W interaction role than N,W interaction and P,W interaction.3. Crude protein,crude ash,crude fat,acid detergent fiber,neutral detergent fiber the best nutrients required for the combination of water and fertilizer was: 300 kg/hm²(N)+450 kg/hm²(P)+2300m³/hm²(W),but the highest content of dry matter treatment was: 300 kg/hm²(N)+450 kg/hm²(P)+1150m³/hm²(W).4. In the regression equation of chlorophyll, the size of role each factor was: N>P>W and N was positive,P,W was negative, P-W interaction was positive,the highest treatment of chlorophyll content was: N 300kg/hm²,P₂O₅ 0kg/hm²,soil moisture content was 5-10%;In the regression equation of nitrate reductase, the role of various factors were :W>N>P and for all positive, N-W and P-W interaction were positive,the highest treatment of nitrate reductase activity was: N 300kg/hm²,P₂O₅ 450kg/hm²,soil moisture content was 5-10%.5. The tendency of the soil fertility as follows: the content of soil organic matter decreased after harvest.The content of soil total nitrogen increased and the content of soil alkali-hydro nitrogen decreased compared with that before fertilization. In contrast to before-fertilization in the second year,the content of available phosphorus in soil decreased after harvest while the content of soil available phosphorus increased for two cuttings in the next year.Then the content of soil available potassium for each cutting decreased.