贺兰山东麓荒漠植物对土壤化学性质和酶活性的影响

Effects of Different Desert Plants on the Soil Chemical Properties and Enzyme Activities in Helanshan Eastern Region

为了明确不同荒漠植物对土壤化学性质和酶活性的影响,选择了荒漠化草原上5种典型的植物群落——贺兰山丁香(Syringa pinnatifolia var.alanshanica)、斑子麻黄(Ephedra rhgtidosperma Pachom)/鹰爪柴(Convolvulus gortschakovii Schrenk)、灰榆(Ulmus glaucescens)/蒙古扁桃(Amygdalus mongolica)、松叶猪毛菜(Salsola laricifolia)和红砂(Reaumuria soongorica),采集植物冠下的土壤,并以各群落中相应的裸地土壤作为对照,采用调查采样和实验分析相结合的方法,测定不同土壤样品的化学性质及酶活性,并采用Spearman相关系数和RDA分析不同指标的相关性。结果显示:(1) 7种植物均能提高N/P比,丁香使有机质增加最多,增加了119.2%,灰榆使速效钾增加最多,增加了211.7%,红砂使速效氮增加最多,增加了148.8%;(2) 7种植物均能增加两种或多种土壤酶的活性,亦使土壤中一种或多种营养成分提高,但不同植物对土壤养分的富集作用差异较大,其中,贺兰山丁香、灰榆、松叶猪毛菜、蒙古扁桃和红砂对土壤养分的富集效果较佳,是较为理想的植物群落类型,而斑子麻黄和鹰爪柴对土壤养分的改善作用很小;(3)土壤酶活性与各化学性质间存在一定的关联,植物能促使酶活性与各化学性质间的关系更密切;(4)荒漠植物使土壤酶与有机质、全钾、全氮、速效钾、速效氮等营养成分都具有显著正相关关系,其中,速效钾和有机质是影响不同植物群落下土壤酶活性的最重要因素。综上,贺兰山保护区自然生境中的优势植物群落对土壤酶和营养成分的富集作用具有明显的物种效应,贺兰山丁香、灰榆、松叶猪毛菜、蒙古扁桃和红砂对荒漠土壤的修复作用较好。

To explore the effects of different desert plants on the soil chemical properties and enzyme activities,five typical plant communities in Helanshan Eastern Region,Syringa pinnatifolia var.alanshanica,Ephedra rhgtidosperma Pachom/Convolvulus gortschakovii Schrenk,Ulmus glaucescens/Amygdalus mongolica,Salsola laricifolia and Reaumuria soongorica,were selected as the research area.Seven soil samples under the plant crown were collected as the treated group and five soil samples were collected as the control group from the bare land in the five typical plant communities.Based on field investigation,the chemical properties and enzyme activities of different soil samples were determined and the correlation of different indexes was analyzed by Spearman correlation and RDA.Results were shown as follows:(1)All the seven plants increased the N/P ratio.The organic matter was increased the most by S.pinnatifolia var.alanshanica,increased by 119.2%.The available K was increased the most by U.glaucescens,increased by 211.7%.The available N was increased the most by R.soongorica,increased by 148.8%.(2)All the seven plants increased the activities of two or more soil enzymes and the contents of one or more nutrients in the soil.However,the effect of nutrients enrichment differed a lot among different plants.The nutrients were efficiently enriched by S.pinnatifolia var.alanshanica,U.glaucescens,S.laricifolia,A.mongolica,and R.soongorica,indicating they were the appropriate desert plants for desert soil remediation.On the other hand,E.rhgtidosperma Pachom and C.gortschakovii Schrenk had little effect on improving soil nutrients.(3)There was a correlation between soil enzyme activities and chemical properties,and the relationship was promoted remarkably by the plants.And(4)there was a significant positive correlation between soil enzymes and organic matter,total potassium,total nitrogen,available potassium,available nitrogen and other nutrients,among which organic matter and available potassium were the most important factors affecting soil enzyme activities in different plant communities.In conclusion,the dominant plant communities in the Helan Mountain Nature Reserve demonstrated obvious species effects on the enrichment of soil enzymes and nutrients,with S.pinnatifolia var.alanshanica,U.glaucescens,S.laricifolia,A.mongolica,and R.soongorica providing better remediation effects on desert soil.