连年种植菊芋对滨海盐碱地的生态修复效果与机制

Ecological restoration effect and mechanism of continuous-year cultivation of Jerusalem artichoke on coastal saline-alkali land

[目的]本文通过定位试验,比较了菊芋(耐盐植物)和碱蓬(真盐生植物)对滨海滩涂的生态修复作用,探究菊芋对土壤性质及细菌群落的调控作用及驱动机制,为滩涂植物的引种驯化、开发利用及盐碱地生态修复提供指导意义。[方法]采用样方调查法,对同一生境连续6年种植菊芋和自然碱蓬植被的土壤样本进行采集,分析其理化性质和土壤酶活性,并利用16S rRNA高通量测序技术对土壤细菌群落多样性和组成进行测定。[结果]连年种植菊芋有效降低了盐碱土壤盐含量,改善土壤肥力水平,菊芋根际土壤盐含量约为碱蓬生境土壤的20.65%,有机质、碱解氮、有效磷含量较碱蓬生境土壤分别增加0.54、2.40和1.18倍;与碱蓬植被土壤相比,除过氧化氢酶外,种植菊芋土壤的脲酶、蔗糖酶和碱性磷酸酶活性均显著提高,根际土壤分别提高0.71、1.17和1.44倍。可能由于根系效应的影响,菊芋根际土壤微生物(包括功能菌)大量增殖,但微生物多样性下降。与碱蓬植被土壤相比,种植菊芋土壤的微生物群落结构得到优化,节杆菌属(Arthrobacter)、慢生根瘤菌属(Bradyrhizobium)、假单胞菌属(Pseudomonas)等常见土壤功能菌属丰度显著增加;放线菌门(Actinomarinales)和酸杆菌门(Acidobacteria)的相对丰度在菊芋根际土壤中分别增加12.68%和9.30%,与土壤碱解氮含量和脲酶、蔗糖酶、碱性磷酸酶活性显著正相关,说明土壤细菌群落结构的变化与土壤性质密切相关。[结论]连年种植菊芋加速了土壤脱盐熟化过程,使盐碱地性质发生根本性变化,向农用耕地转变,对于保障我国耕地红线和粮食安全具有重要意义。

[Objectives]In this study,the ecological restoration effects of Jerusalem artichoke(salt-tolerant plant)and Suaeda salsa(halophyte)on coastal saline-alkali land were compared through long-term positioning experiment,which provided guidance for the introduction,domestication,development and utilization of beach plants and ecological restoration of saline-alkali land.[Methods]The soil samples of Jerusalem artichoke continuous cropping for 6 years and S.salsa planted in the same habitat were collected by quadrat survey,and their physicochemical properties and soil enzyme activities were analyzed.The diversity and composition of soil bacterial community were measured by using 16S rRNA high-throughput sequencing technology.[Results]Planting Jerusalem artichoke in successive years effectively reduced the salt content of saline alkali soil and improved soil fertility.The salt content of Jerusalem artichoke rhizosphere soil was about 20.65%of S.salsa habitat soil,and the contents of organic matter,alkali hydrolyzable nitrogen and available phosphorus were 0.54,2.40 and 1.18 times higher than those of S.salsa habitat soil,respectively.In addition to catalase,the activities of urease,invertase and alkaline phosphatase in Jerusalem artichoke soil significantly increased,which were 0.71,1.17 and 1.44 times higher than those in S.salsa soil,respectively.It was possible that the rhizosphere soil microorganisms of Jerusalem artichoke,including functional bacteria,proliferated largely due to the effect of root system,but the microbial diversity decreased.Compared with S.salsa soil,the microbial community structure of Jerusalem artichoke planting soil was optimized,and the abundance of common soil functional bacteria such as Arthrobacter,Bradyrhizobium,Pseudomonas increased significantly;the relative abundance of Actinomarinales and Acidobacteria in Jerusalem artichoke rhizosphere soil increased significantly,and increased by 12.68%and 9.30%,respectively,and was significantly positively correlated with the contents of available phosphorus,alkali hydrolyzable nitrogen and the activities of urease,sucrase and alkaline phosphatase,indicating that the change of soil bacterial community structure was closely related to soil properties.[Conclusions]Planting Jerusalem artichoke in successive years accelerated the process of soil desalting and ripening,and changed the nature of saline-alkali land to agricultural land,which was of great significance for ensuring the red line of cultivated land and food security in China.