不同种植年限苜蓿地土壤环境效应的研究

随着苜蓿种植年限的延长，土壤质量发生一系列变化。为了揭示不同种植年限苜蓿地土壤质量的变化，以毗邻种植的1～5年生苜蓿为研究对象，对土壤水分、养分及微生物的变化进行研究，分析比较不同种植年限苜蓿地土壤质量的变化。结果表明：在苜蓿生长季节内，不同种植年限苜蓿的土壤含水量的时空变化均呈先增加后降低的变化趋势；随种植年限的延长，土壤有机质、全氮、碱解氮含量呈递增趋势，速效钾的含量呈先增加后降低的趋势；各种植年限苜蓿草地土壤微生物群落以细菌占优势，且细菌和放线菌的数量随种植年限的延长呈递增趋势，真菌变化规律不明显，此外4年生苜蓿地微生物总数最大，是其它各种植年限的1.04～2.60倍。说明种植年限对苜蓿草地土壤质量有一定程度的影响，且因种植年限的长短，影响程度也各异。

Effects of planting years of alfalfa on soil quality

In order to reveal the changes in soil quality of different planting years of alfalfa, we analyzed soil moisture, nutrients and microbial population of alfalfa field with one to five planting years. The results showed that as the planting year increased, temporal and spatial variation of soil moisture content exhibited a pattern of increasing first and then decreasing. in addition, soil organic matter, total nitrogen content showed an increasing trend, potassium content increased first and then decreased. In the alfalfa planting soil, microbial community was dominated by bacteria, and the number of bacteria and actinomycetes as planting year increased. However, no obvious trend was found for fungus. In addition, 4-year-old alfalfa total number of microorganisms is the highest among all the treatments. Our findings indicate a substantial influence of planting year on soil quality of alfalfa field.