模拟降雨对黄土高原典型草原土壤化学计量及微生物多样性的影响

以宁夏固原云雾山自然保护区封育19年天然草地为研究对象,利用遮雨棚和滴灌技术对研究区的降水量进行人为调控,系统分析了草原土壤生态化学计量及其微生物多样性在50%、100%和150%不同降雨处理下的响应。结果表明:经过一年的水分控制处理(1)不同降雨梯度对土壤有机碳(SOC)、全氮(TN)、全磷(TP)、碳氮比(C/N)、碳磷比(C/P)、氮磷比(N/P)无显著性影响,但100%降水处理下SOC、TN、TP、N/P均高于50%和150%降水处理。(2)在3种不同降水梯度处理下,各处理不同土层深度SOC、TN、TP、C/N、C/P、N/P有显著性差异(P<0.05),且随土层深度加深,土壤化学计量及其比值逐渐降低。(3)降雨对土壤微生物多样性影响不大,但増雨和减雨均能增加真菌多样性,引起细菌菌群结构发生相应的变化,且真菌优势种相对丰度随降雨增加呈下降趋势。(4)土壤SOC、TP、C/N与微生物多样性无显著相关,C/P、N/P与细菌多样性呈显著负相关关系(P<0.05),与真菌多样性呈极显著正相关关系(P<0.01)。短期(一年)降雨变化对土壤养分及微生物多样性影响较弱,但...

Effects of different precipitation treatments on soil ecological chemistry and microbial diversity in the Loess Plateau

In this study, the natural grassland (which has been shielded for 19 years) of the Ningxia Yunwushan Grassland Nature Reserve in Guyuan was used as the research object. The precipitation in the study area was artificially regulated by the measure of artificial increase and decrease of rain using rainwater shed and drip irrigation technologies, and the responses of the ecological stoichiometry and microbial diversity of grassland soil were systematically analyzed under 50%, 100%, and 150% rainfall treatments. The results show that after one year of precipitation change, (1) different rainfall gradients had no significant effect on the soil organic carbon(SOC), total nitrogen(TN), total phosphorus(TP), carbon-nitrogen ratio(C/N), carbon-phosphorus ratio(C/P), and nitrogen-phosphorus ratio(N/P), but the SOC, TN, TP, and N/P under 100% simulated rainfall treatment were higher than those under 50% and 150% respectively. (2) The SOC, TN, TP, C/N, C/P, and N/P of different soil depth were significantly different (P<0.05) under the three different precipitation gradient treatments. As the depth of the soil deepened, the soil stoichiometry and its ratio gradually decreased. (3) Precipitation had little effect on soil microbial diversity, but both 150% and 50% precipitation can increase fungal diversity, causing changes in the fungal flora structure, and the relative abundance of fungal dominant species decreased under 150% precipitation. (4) There was no significant correlation between the SOC, TP, and C/N and microbial diversity. The C/P and N/P were significantly negative correlated with the bacterial diversity (P<0.05), and showed a significant positive correlation with the fungal diversity (P<0.01). Therefore, Short-term (one year) precipitation changes have weak effects on the soil nutrient and microbial diversity, but the microbial diversity is closely related to soil nutrients. These results will provide a proof for further analysis of the effects of changing precipitation on soil ecological stoichiometry and microbial diversity on the ecological function of temperate grassland.