接种苜蓿根瘤菌对西藏苜蓿生长及土壤理化性质的影响

Effects of Inoculation of Alfalfa Rhizobium on Alfalfa Growth and Soil Physical and Chemical Properties in Tibet

为探索苜蓿根瘤菌接种效果,以未包衣的‘中兰1号’苜蓿为供试苜蓿品种,设计苜蓿根瘤菌拌种、拌土接种方式,以及在拌土、拌种的基础上增施复合菌剂的处理。研究发现:①苜蓿接种根瘤菌对苜蓿株高、地上部生物量、根系生长积累有促进作用;②接种根瘤菌增加苜蓿根瘤菌数量和重量;③土壤有机质含量和全氮含量较播前土壤有不同程度提高;但土壤全磷、全钾含量较播前降低,消耗了土壤中磷钾元素;④在接种根瘤菌的基础上增施复合菌剂(固氮解磷解钾+枯草芽孢杆菌)促进土壤中磷、钾元素的使用,且增加土壤中速效磷、速效钾含量;⑤根瘤菌接种(拌土或拌种)对土壤微生物量C、N都有增加,表明土壤中微生物量和活性都有不同程度增强。由此可得,接种苜蓿根瘤菌促进苜蓿植株生长和根瘤菌的形成,能显著提高苜蓿的固氮能力和固氮潜力,改善土壤营养结构和活性。

In order to explore the effect of inoculation Alfalfa rhizobium,‘Zhonglan No. 1’alfalfa uncoated was taken as the tested alfalfa variety. Alfalfa rhizobium mixed with soil and alfalfa seeds,and supplied compound bacterial agent on the basis of inoculation Alfalfa rhizobium. The results showed that:(i) Inoculation alfalfa rhizobium promoted alfalfa plant height,biomass,and root growth;( ii) Inoculation alfalfa rhizobium increased the number and weight of alfalfa rhizobium;( iii) After alfalfa was harvested,the soil organic matter and total nitrogen increased in inoculation alfalfa rhizobium compared with that before sowing;But soil total phosphorus and total potassium content was decreased than that before sowing;( iv) Based on inoculating rhizobium,the treatment of supplying compound bacterium agent( nitrogen fixing,phosphorus dissolving and potassium + Bacillus subtilis) promoted the using of phosphorus and potassium in soil and increased the content of available phosphorus and potassium in soil;( v) After inoculation rhizobium( soil mixing or seed mixing),soil microbial biomass C,N and microbial biomass increased,it indicated that soil microbial biomass and activity increased. It is concluded that the inoculation alfalfa rhizobium can promote the growth of alfalfa plants and rhizobium formation. It can significantly improve the nitrogen fixation capacity and nitrogen fixation potential of alfalfa,and improve the soil nutrient structure and activity.