论文部分内容阅读
以古尔班通古特沙漠南缘典型流域(玛纳斯河、吉木萨尔河、三工河、四工河、水磨河)的绿洲农田与毗邻荒漠土壤为研究对象,采用磷脂脂肪酸(PLFA)方法分析不同开垦年限的土壤微生物生物量、群落结构、多样性变化特征。结果表明:荒漠开垦后,土壤微生物总PLFA含量、真菌PLFA、细菌PLFA、革兰氏阳性菌(G~+)和革兰氏阴性菌(G-)PLFA含量均显著增加。荒漠开垦5 a内,细菌PLFA与G-PLFA增长更强烈,使得真菌PLFA/细菌PLFA比值降低了48%,G~+PLFA/G-PLFA比值(革兰氏阳性菌与革兰氏阴性菌的PLFA比值)降低了67%。但随着开垦年限的延长,这两个比值没有显著变化,表明与开垦年限相比,荒漠的开垦行为对土壤微生物群落结构有着更加强烈的影响。随着开垦年限的增加,土壤微生物群落多样性总体呈上升趋势。虽然荒漠在开垦50 a后多样性指数略有下降,但仍远高于荒漠土壤。土壤微生物总PLFA含量和大部分菌群PLFA含量与土壤电导率显著负相关,与全氮和有机碳显著正相关。荒漠在开垦过程中灌溉增加了土壤水分且降低了土壤盐分,全氮和有机碳含量增加,这些改变是土壤微生物群落变化的主要原因。荒漠开垦有助于提高土壤微生物PLFA含量、改善土壤微生物的群落结构、丰富土壤微生物群落多样性,有利于土壤质量的提高。
Taking the oasis farmlands and the adjacent desert soils in the typical watershed (Manas River, Jimsar River, Sangong River, Sijiang River, and Shuimu River) of the southern margin of the Gurbantunggut Desert as research objects, phospholipid fatty acid (PLFA ) Method was used to analyze the changes of soil microbial biomass, community structure and diversity under different reclamation years. The results showed that total PLFA contents, PLFA contents, PLFA contents, G ~ + contents and PLF contents of Gram-negative bacteria (G-) increased significantly after desert reclamation. Within 5 days of desert reclamation, the bacterial PLFA and G-PLFA increased more strongly, which decreased the ratio of PLFA to bacterial PLFA by 48%. The ratio of G + PLFA / G-PLFA (Gram-positive bacteria and Gram-negative bacteria PLFA ratio) was reduced by 67%. However, with the extension of reclamation years, the two ratios did not change significantly, indicating that desert reclamation had a stronger influence on soil microbial community structure than reclamation years. With the increase of reclamation years, the diversity of soil microbial community is generally on the rise. Although the diversity index of deserts declined slightly after 50 years of reclamation, it is still far higher than the desert soil. The total PLFA content of soil microorganisms and PLFA content of most of the flora were negatively correlated with soil electrical conductivity, and positively correlated with total nitrogen and organic carbon. Irrigation during desertification increased soil moisture and decreased soil salinity, total nitrogen and organic carbon, which were the main reasons for the changes of soil microbial community. Desert reclamation helps increase soil microbial PLFA content, improve the community structure of soil microorganisms, enrich the diversity of soil microbial communities, and improve soil quality.