模拟降水量变化对荒漠草原土壤酶活性的影响及其相关因素分析
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引用本文:许艺馨,余海龙,李春环,韩 翠,王晓悦,黄菊莹.模拟降水量变化对荒漠草原土壤酶活性的影响及其相关因素分析[J].西北植物学报,2021,41(11):1912~1923
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作者单位
许艺馨1,2,3,4,余海龙4,李春环4,韩 翠5,王晓悦1,2,3,黄菊莹1,2,3* (1 宁夏大学 生态环境学院, 银川 750021
2 西北土地退化与生态恢复国家重点实验室培育基地, 银川 750021
3 西北退化生态系统恢复与重建教育部重点实验室, 银川 750021
4 宁夏大学 地理科学与规划学院, 银川 750021
5 宁夏大学 农学院, 银川 750021) 
基金项目:国家自然科学基金(31760144);
中文摘要:为明确荒漠草原土壤酶活性对降水格局改变的响应机制, 该研究基于宁夏荒漠草原降水量不同梯度变化(减少50%、减少30%、自然降水、增加30%和增加50%)的野外试验(2014年开始试验), 于2016年5-7月采样, 测定分析不同降水梯度2年后对土壤酶活性的影响, 并分析酶活性与植物生物量、微生物生物量C∶N∶P生态化学计量特征以及土壤理化性质的关系。结果表明: (1)与自然降水量相比, 减少30%降水量对3种土壤酶活性均无显著影响, 减少50%降水量显著降低了土壤蔗糖酶活性(P < 0.05); 增加降水量显著提高了土壤蔗糖酶和磷酸酶活性(P < 0.05), 但对脲酶活性无显著影响。(2)减少降水量对植物生物量影响较小(尤其减少30%降水量), 但不同程度地降低了微生物生物量C、N、P, 提高了微生物生物量C∶N和C∶P; 增加降水量则不同程度提高了植物生物量及微生物生物量C、N、P。(3)土壤蔗糖酶和磷酸酶活性随植物及微生物生物量增加而增加; 对土壤酶活性影响显著的土壤因子包括: 含水量、NO3- N、NH4+ N、C∶P、有机C、全N、C∶N和pH (P < 0.05)。研究认为, 减少降水量(尤其是减少30%降水量)对土壤酶活性影响较小, 增加降水量促进了植物的生长、刺激微生物活性, 进而提高了土壤酶活性, 但随着植物生物量增加, 土壤有机C输入增多, 磷酸酶活性相应增强并促进了有机P的矿化, 导致土壤微生物P限制增加。
中文关键词:降水格局改变  荒漠草原  酶活性  植物生物量  微生物生态化学计量特征
 
Effects of Simulated Precipitation on Soil Enzyme Activities in a Desert Steppe of Northwest China and Their Related Influencing Factors
Abstract:In order to clarify the responses of soil enzyme activities to changing precipitation regimes in desert steppe, we carried out this study based on field experiments (started in 2014) of different gradient changes of precipitation (50% reduction, 30% reduction, control, 30% increase and 50% increase) in a desert steppe in Ningxia. The sampling time was from May to July in 2016. The activities of soil enzymes were studied after two years of treatments, their relationships with plant biomass, microbial biomass C∶N∶P ecological stoichiometry, and soil physicochemical properties were analyzed too. The results showed that: (1) compared with natural precipitation, the 30% reduction in precipitation did not significantly affect the three soil enzyme activities (P > 0.05), while the 50% reduction in precipitation significantly decreased the invertase activity (P < 0.05). Increased precipitation significantly increased the activities of invertase and phosphatase (P < 0.05), whereas no significant effect on urease activity (P > 0.05). (2) Decreased precipitation had little effect on plant biomass (especially 30% reduction), whereas it reduced microbial biomass C, N, P and increased microbial biomass C∶N and C∶P to varying degrees. Increased precipitation increased plant biomass and microbial biomass C, N, P to certain degrees. (3) Mostly, the activities of soil invertase and phosphatase increased with the increasing plant and microbial biomass. The soil factors that had significant influences on soil enzyme activities included water content, NO3- N, NH4+ N, C∶P, organic C, total N, C∶N, and pH (P < 0.05). The results of this study suggest that short term reduction in precipitation (especially 30% reduction) would have little influences on soil enzyme activities in the studied desert steppe; increasing precipitation could promote plant growth and microbial activity, and then improve the activity of invertase. However, with the increase of plant biomass accumulation, more organic C is sequestrated in soils, the activity of phosphatase in soils increased correspondingly and promoted the mineralization of organic P, resulted in the aggravation of P limitation of microbes.
keywords:changing precipitation regimes  desert steppe  enzyme activities  plant biomass  microbial biomass ecological stoichiometry
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