施肥对不同品种苜蓿生产力及土壤肥力的影响

研究了不同施肥处理对生长7年的3个紫花苜蓿品种的产量及土壤养分的影响。结果表明，NP配施和单施K肥对苜蓿均有显著的增产效果，不同施肥对不同品种的生产力影响效果不同。N30P120处理巨人201+Z和牧歌401+Z产量最高，分别比对照增产41.1%和74.8%；单施K60处理，路宝比对照增产了76.7%。种植苜蓿可以提高土壤氮的有效性，生长7年的苜蓿根系固氮在土壤仍有累积。种植苜蓿，不施肥处理土壤全氮含量均有不同程度增加，而土壤全磷和全钾略有下降。随磷肥用量的增加而增加，N30P120处理土壤速效磷增加11.45～41.7 mg/kg；单施钾肥，土壤速效磷含量提高了3.71～4.41 mg/kg，全钾含量增加了0.06～1.69 mg/kg。

Effect of fertilization on productivity different producing performance alfalfa varieties and soil fertility

The report studied the effects of different fertilizer treatments on the growth of the 7th years-old of 3 different production performance alfalfa( Medicago sativa) varieties, as well as changes in soil nutrients. The results showed: NP combined application and K fertilization alone can significantly increase the yield of all different alfalfa varieties. Different fertilization shows different impact on the productivity of different varieties. When applied N_(30)P_(120), the highest forage production was obtained for both Ameri Stand 201 + Z and Ameri Graze 401 + Z reached, increasing 41.1% and 74.8% more than that of non-fertilizer respectively. When applied K_(60), Lobo will gain the largest production increase (76.7 % ).Planting alfalfa can improve the soil N availability, and it is accumulated in soil that the nitrogen was firmed by roots of the 7th years-old alfalfa (sentence is not clear). The soil N content of non-fertilization increases with alfalfa planting, but total P, total K in soil decreased. The impacts of fertilization on soil fertility are different with different alfalfa varieties planting. The soil available P content increases with increases of P fertilization. Applying K alone can raise the soil available P content (3.71-4.41 mg/kg) and total K content (0.06-1.69 mg/kg).