紫花苜蓿绿肥对水稻产量和土壤肥力的影响

以紫花苜蓿（Medicago sativa）为绿肥植物，利用南方冬闲田种植紫花苜蓿绿肥，研究紫花苜蓿绿肥（茎叶粉碎还田）和氮肥处理对水稻（Oryza sativa）生长、土壤有机质、土壤总氮、土壤速效磷和土壤速效钾含量的影响。结果表明，紫花苜蓿绿肥和紫花苜蓿绿肥+氮肥处理的水稻产量分别比不施氮肥处理增加了48.2%和72.1%，同时绿肥+氮肥处理的水稻产量比施氮肥处理增加了8.6%。苜蓿绿肥处理显著提高了土壤有机质、总氮、速效磷和速效钾的含量，改善了稻田土壤的理化性状；同时，苜蓿绿肥+氮肥处理对增加土壤有机质的作用效果最为明显，并且有效促进了土壤磷和钾的活性，增加了水稻对土壤磷和钾的吸收，从而促进水稻增产。研究反映出紫花苜蓿作为绿肥能够有效改善稻田土壤营养，提高氮肥利用效率，促进水稻增产，是我国南方利用冬闲田种植绿肥、改良农田土壤的又一重要绿肥植物资源。

Effects of alfalfa green manure on rice yield and soil fertility

A field experiment was carried out to determine the effects of alfalfa green manure and nitrogen fertilizer on rice yield,soil organic matter,soil nitrogen,soil available P and soil available K by planting alfalfa as green manure into winter fallow fields in the south region of China.The results of this study showed that the rice yield in the alfalfa manure treatment and alfalfa manure+nitrogen treatment increased by 48.2% and 72.1%,respectively.Alfalfa green manure significantly increased the contents of soil organic matter,total nitrogen,available P and available K,implying that Alfalfa green manure improved the physical and chemical properties of soil.The alfalfa+nitrogen treatment effectively improved the soil organic matter content and P and K activity,which promoted the rice to uptake more soil P and K,resulting in the increase of rice production.This study suggested that alfalfa was an effective green manure for improving rice soil quality,increasing nitrogen efficiency,and increasing rice yield,and would be a very good green manure resource for improving farm land quality in the south region of china.