柠条对盐碱地植被组成及土壤特性的影响

Impact of Caragana Fabr. plantation on plant community and soil properities of saline-alkali wasteland

研究了山西省大同盆地毛皂试验站盐碱滩地人工种植柠条后植被组成、微生物数量、土壤养分特征及变化规律。结果表明:(1)人工种植柠条后,增加了植物物种的丰富度,植物科、属、种的数量均有所增加。不同生境中植物组成结构发生变化,主要优势种发生了根本性变化,披碱草在盐碱地中为绝对优势种,在柠条林下已消失。(2)不同生境中土壤真菌、细菌、放线菌数量的变化规律为:多年生柠条林地土壤>火扰后柠条林地土壤>盐碱地土壤,柠条根际真菌数量最多,而对于细菌和放线菌并没有表现出明显的根际效应。(3)由于成土基质相同,多年生人工柠条林与其毗邻的原生盐碱滩地的全氮、全磷、全钾含量基本一致,但速效养分显著提高,有效磷、速效钾、硝态氮、氨态氮和有机质含量柠条林分别是盐碱滩地的3.4、1.4、1.2、1.4倍和1.7倍。多年生人工柠条林土壤全盐量比原生盐碱滩地显著减少(p<0.01),阳离子交换量和微量营养元素Fe、Mn、Zn的含量比原生盐碱滩地的显著增加(p<0.05)。随着柠条的定植,土壤养分保蓄功能以及保证植物良好生长的生态功能明显改善。

The effects of planting of Caragana Fabr. on vegetation, microbial community and characteristics and changes in soil nutrients of saline-alkali wasteland were investigated in Maozao Experimental Station located in Datong Basin （113~E, 39~55＇N）, Shanxi Province, China. After the planting of Caragana, the number of plant families, genus and species increased, indicating that the improvement of plant diversity, and vegetation profile underwent changes. Elymus dahuicus had been the absolute dominant species on saline-alkali wasteland but disappeared in Caragana-distributed lands, showing an alteration in dominant species in the community. The number of fungi, bacteria and actinomycetes in soils of different habitats showed a trend as follows： perennial Caragana Fabr. forest 〉 Caragana forest after fire disturbance 〉 Saline- alkali. The largest number of fungi were found in Caragana rhizosphere in comparison to other plants, but there was no obvious increase in the bacteria and actinomycetes found. Total nitrogen, phosphorus and potassium content remained essentially unchanged in areas with perennial Caragana compared to the primary saline-alkali wasteland. However, available nutrients in Caragana-distributed land increase significantly, with phosphorus, potassium, nitrate, ammonia nitrogen and organic matter increasing by 3.4 times, 1.4 times, 1.2 times, 1.4 times and 1.7 times, respectively compared to those of the saline-alkali wasteland. Furthermore, the total salt content of soil in Caragana Fabr. forest was significantly lower than that of the soil from saline-alkali wasteland （p 〈0.01 ）. There was significant increase in content of available Fe, Mn, Zn in Caragana Fabr. forest compared to saline-alkali wasteland soil （p 〈 0.05 ）. From the results, we conclude that growing of Caragana exerts positive effects on fertility preserving capacity of soil and helps improve ecological function of soil to provide better environment for other plant species in saline-alkali wasteland.