Liu Taicong, Chen Zhe, Rong Li, Duan Xingwu
Institute of International Rivers and Eco-Security, Yunnan University, Kunming 650500, China.
Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming 650091, China.
Microorganisms. 2022 May 2;10(5):956. doi: 10.3390/microorganisms10050956.
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 and 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.
干热河谷是中国西南部一个独特的地理区域，在这里，陡坡开垦和土地利用的加速变化导致了土地退化，加剧了土壤侵蚀，对土壤肥力产生了深远影响。土壤微生物在土壤肥力中起着关键作用，但土地利用变化对干热河谷土壤微生物的影响尚不清楚。在这里，我们比较了甘蔗地（SL）、林地（FL）、由前玉米地（ML）转化而来的荒地（BL）以及ML对照等典型干热河谷土地利用方式下土壤微生物群落组成和土壤肥力的特征及驱动因素。我们的结果表明，与ML和FL相比，BL和SL的土壤有机碳（SOC）、总氮（TN）和总钾（TK）含量降低。这表明将ML转化为SL以及撂荒ML有可能降低土壤肥力。我们还发现，SL和BL中分别不存在真菌门 和 ，这表明土地利用从ML转变为SL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、SOC和有效钾（AK）含量呈正相关，而真菌门与AK呈正相关。土地利用通过对土壤湿度、黏土和AK含量的影响间接影响细菌门的相对丰度，通过对黏土和AK含量的影响间接影响真菌门的相对丰度。此外，土地利用对细菌的影响大于对真菌的影响，这表明细菌群落对土地利用变化更为敏感。纳入土壤碳保护、钾肥添加和合理灌溉的管理措施有望有益于干热河谷植物 - 土壤系统的稳定性。
