氮、磷、钾、硫肥对苜蓿产量和品质影响

采用4因素(氮、磷、钾、硫)，3水平进行苜蓿施肥试验，结果表明，施肥对苜蓿有明显的增产作用，尿素225kg／hm^2、过磷酸钙562．5kg／hm^2、硫酸钾675kg／hm^2、硫磺粉75kg／hm^2时产量最高分别为：14550，14550，13678．5，12789kg／hm^2，分别高于对照28．3％，31．1％，20．6％，13．7％。施肥可提高苜蓿粗蛋白含量，硫酸钾的效果最明显：第一茬在225kg／hm^2时粗蛋自含量为19．4％，高于对照27．9％；第二茬450kg／hm^2时粗蛋白含量为20．1％，高于对照12．5％；施适量的氮、磷、钾可促进对其他养分的吸收。施硫磺粉对土壤养分没有明显的影响。施尿素、过磷酸钙、硫磺粉均能提高种植苜蓿经济效益，每公顷分别增值1476．9，1439．1，750．3元。

Influence of nitrogen, phosphorus, potassium and sulphur fertilizer on alfalfa's yield and quality

In this article the experiment was carried out to adopt 4 factors (nitrogen, phosphorus, potassium and sulphur) and 3 levels with alfalfa fertilizer. The results indicated that fertilizer could increase the yield of alfalfa obviously. When urea 225 kg/hm~2, calcium superphosphate 262.5 kg/hm~2, potassium carbonate 675 kg/hm~2,and sulphur powder 75 kg/hm~2 were applied, the high yield was obtained respectively as follows:14 550,14 550, 13 678.5, 12 789 kg/hm~2. They were higher than the control respectively as follows:28.3%, 31.1%, 20.6%, and 13.7%. The fertilizer could increase the protein content of alfalfa, the potassium carbonate produced the best effect. When the first crop was at 225 kg/hm~2, the protein was (19.4%,)higher than the control 27.9%;When the second crop was at 450 kg/hm~2, the protein content was 20.1%, higher than the control 12.5%. The proper amount of nitrogen, phosphorus and potassium could promote alfalfa nutrient absorption. Sulphur powder has no remarkable effect on soil nutrition. Urea, calcium superphosphate and sulphur powder all could increase economic efficiency of alfalfa planting respectively:1476.9 yuan/hm~2, 1439.1 yuan/hm~2 and 750.3 yuan/hm~2.