不同人工草地对干旱区弃耕地土壤理化性质及微生物数量的影响

Effect of Different Artificial Grassland on Soil Physico-chemical Properties and Microbial Quantities of Abandoned Land in Arid Area

在宁夏干旱区弃耕地种植6种牧草建植人工草地,对表层土壤理化性质、土壤养分含量及微生物数量进行研究,探讨不同人工草地对弃耕地土壤理化性质及微生物数量的影响。结果表明:各人工草地的土壤容重、pH、全盐均低于撂荒地,其中全盐含量显著降低;各禾本科草地保水蓄水能力均强于豆科草地,以披碱草的效果最佳;各人工草地的土壤有机质、全氮、速效氮和速效磷含量均显著高于撂荒地,且豆科草地提高土壤有机质、全氮、全磷、速效氮含量的效果强于禾本科草地,效果大小为紫花苜蓿>沙打旺>草木樨;禾本科草地提高速效磷、速效钾含量的效果强于豆科草地,效果大小为披碱草>扁穗冰草>蒙古冰草;各人工草地表层土壤细菌、真菌和放线菌数量均显著高于撂荒地;各豆科草地细菌数量均显著高于各禾本科草地,而真菌数量较禾本科草地少,紫花苜蓿和沙打旺草地细菌、放线菌数量均显著高于其他人工草地;禾本科中披碱草草地细菌数量显著多于扁穗冰草和蒙古冰草;土壤水分与放线菌、真菌数量呈显著或极显著正相关;土壤全盐与放线菌、真菌数量呈极显著负相关;土壤有机质、全氮、全磷、速效氮、速效磷含量与细菌、放线菌数量呈显著或极显著正相关,土壤全钾、速效磷、速效钾含量与真菌呈极显著正相关。

Six grasses were planted and the topsoil physico-chemical properties and microbial quantities were compared. The results showed that soil bulk density, pH, total salt of artificial grasslands were lower than that of wasteland and total salt decreased significantly. Water conservation ability of gramineae grasslands was stronger than legume grasslands, and Elymus dahuricus grassland was best. Soil organic matter, total nitrogen, available nitrogen and available phosphorus contents of artificial grasslands were significantly higher than that of wasteland and legume grasslands which could improve soil organic matter, total nitrogen, total phosphorus and available nitrogen, the order of effect was Medicago sativa 〉Astragalus adsurgens Melilotus suaveolens. The improvement of available phosphorus and available potassium of gramineae grasslands was stronger than that of legume grasslands. The effect size was Elyrnus dahuricus 〉Agropyron cristatum 〉Agropyron rnongolicum. The quantities of bacteria, actinomycetes and fungi in soil of artificial grasslands were higher than those of wasteland. The bacteria quantity of legume grasslands were higher than those of gramineae grasslands, but fungi quantity were opposite. The amount of bacteria and actinomyces of Medicago sativa grassland and Astragalus adsurgens grassland were significantly more than those of other artificial grasslands. The amount of bacteria in Elyrnus dahuricus grassland were more than those of Agropyron cristatum and Agropyron mongolicum. The soil moisture had positive correlation with the amount of actinomyces and fungi and the soil total salt had negative correlation with the amount of actinomyces and fungi. The amount of bacteria and actinomyces showed positive correlation with soil organic matter, total nitrogen, total phosphorus, available nitrogen and available phosphorus. The amount of fungi showed positive correlation with soil total potassium, available phosphorus and available potassium.