不同改良措施对宁夏盐碱地土壤微生物及苜蓿生物量的影响

为了掌握土壤微生物特征及牧草生长对宁夏盐碱地不同改良措施的响应，采用田间实验，研究了秸秆、有机肥、烟气脱硫废弃物、盐碱地改良剂4个改良措施对宁夏盐碱地土壤微生物数量、微生物群落多样性及苜蓿生物量的影响及其之间的相关关系。结果表明：各改良措施对苜蓿的株高和产量都有不同程度的促进作用，改良后苜蓿株高增加了13．8％-33．3％，苜蓿干重增加了21．9％-125．0％，依次表现为有机肥〉秸秆〉改良剂〉脱硫废弃物〉对照。各改良措施增加了土壤微生物群落对碳源的利用能力、丰富度指数和Shannon多样性指数，主成分分析表明对土壤微生物影响较大的主要碳源有2-羟基苯甲酸，∞环糊精，口木糖，苯基乙胺，糖原等；脱硫废弃物、改良剂、有机肥处理增加了土壤微生物总数中细菌的比例，降低了放线菌和真菌的比例；各处理土壤细菌数量、放线菌数量、微生物多样性与苜蓿株高、产量之间成显著（P〈0．01）或极显著正相关关系（P〈0．05），说明盐碱地土壤细菌数量、放线菌数量、微生物多样性微生物可以作为盐碱地改良效果评价的生物指标。

Effect of Microbial Diversity and Alfalfa Biomass in Different Soil Improvement Measures in Saline-alkali Soil in Ningxia

In order to know the response of soil microbial characteristics and grass growth on different improvement measures in saline-alkali soil in Ningxia, the effects of soil microflora, microbial community diversity and the correlation analysis among soil microbial diversity, microorganisms number, and alfalfa biomass were studied in a field experiment after applied with straw, organic fertilizer, flue gas desulfurization waste and saline-alkali soil amendment in saline-alkali soil in Ningxia. The results showed that： four improvement measures had a clear role in promoting the alfalfa plant height and yield, alfalfa plant height increased by 13.8% to 33.3%, alfalfa dry weight increased by 21.9% to 125.0%, the order followed by the performance of organic fertilizer 〉 straw 〉 improved agent desulfurization waste 〉 control. The four improvement measures increased the soil microbial community carbon source utilization capacity, richness anddiversity index, principal component analysis showed that, the greater impact carbon source on soil microbial were 2-hydroxy acid, alpha- cyclodextrinrefined, D-xylose, phenylethylamine, glycogen, etc. Desulfurization waste, conditioner and organic fertilizer treatments increased the proportion of bacteria in the soil microbial amount, reducing the proportion of actinomycetes and fungi. The positive significant correlation existed between soil microbial quantity, microbial diversity and the alfalfa plant height, yield of each treatment. That mean the saline-alkali soil bacteria amount, actinomycetes amount, microbial diversity could be used as biological indicators of the effects evaluation in saline-alkali soil improvement.