干热河谷是中国西南地区一个独特的地理区域,在那里,陡坡耕种和土地利用加速变化导致土地退化,加剧了土壤侵蚀,对土壤肥力有深远的影响。土壤微生物在土壤肥力中起着关键作用,但是土地利用变化对干热河谷土壤微生物的影响尚不为人所知。这里,我们比较了甘蔗土地(SL)的典型干热河谷土地利用中土壤微生物群落组成和土壤肥力的特征和驱动因素,林地(FL),从以前的玉米地(ML)转换而来的贫瘠土地(BL),ML控制我们的结果表明,BL和SL降低了土壤有机碳(SOC),总氮(TN),和总钾(TK)与ML和FL相比。这表明ML转换为SL和放弃ML有可能降低土壤肥力。我们还发现SL和BL中不存在真菌门动物放生菌和芽生菌,分别,表明从ML到SL的土地利用变化降低了细菌群落的多样性。冗余分析表明,细菌门的相对丰度与TN呈正相关,SOC,和有效钾(AK)含量,真菌门与AK呈正相关。土地利用通过对土壤水分的影响间接影响细菌门的相对丰度,粘土,和AK内容,以及真菌门通过对粘土和AK含量的影响。此外,土地利用对细菌的影响大于对真菌的影响,表明细菌群落对土地利用变化更敏感。纳入土壤碳保护的管理制度,钾的添加,明智的灌溉预计将有利于干热河谷植物-土壤系统的稳定性。
The Dry-Hot Valley is a unique geographical region in southwestern China, where steep-slope cultivation and accelerating changes in land-use have resulted in land degradation and have aggravated soil erosion, with profound impacts on soil fertility. Soil microbes play a key role in soil fertility, but the impact of land-use changes on soil microbes in the Dry-Hot Valley is not well known. Here, we compared characteristics and drivers of soil microbial community composition and soil fertility in typical Dry-Hot Valley land uses of sugarcane land (SL), forest land (FL), barren land (BL) converted from former maize land (ML), and ML control. Our results showed that BL and SL had reduced soil organic carbon (SOC), total nitrogen (TN), and total potassium (TK) compared to ML and FL. This indicated that conversion of ML to SL and abandonment of ML had the potential to decrease soil fertility. We also found that fungal phyla Zoopagomycota and Blastocladiomycota were absent in SL and BL, respectively, indicating that land-use change from ML to SL decreased the diversity of the bacterial community. Redundancy analysis indicated that the relative abundance of bacterial phyla was positively correlated with TN, SOC, and available potassium (AK) content, and that fungal phyla were positively correlated with AK. Land-use indirectly affected the relative abundance of bacterial phyla through effects on soil moisture, clay, and AK contents, and that of fungal phyla through effects on clay and AK contents. In addition, land-use effects on bacteria were greater than those on fungi, indicating that bacterial communities were more sensitive to land-use changes. Management regimes that incorporate soil carbon conservation, potassium addition, and judicious irrigation are expected to benefit the stability of the plant-soil system in the Dry-Hot Valley.