降水改变下撂荒草地的化学计量失衡改变调节土壤呼吸  

Stoichiometric Imbalance of Abandoned Grassland Under Precipitation Changes Regulate Soil Respiration

作　　者：王佳懿 王兴 王源茁 房景博 夏开拉·阿克拜 祖丽皮耶·居热艾提 杨改河[1,2] 任成杰 韩新辉[1,2] WANG Jia-yi;WANG Xing;WANG Yuan-zhuo;FANG Jing-bo;Xiakaila Akebai;Zulipiye Jureaiti;YANG Gai-he;REN Cheng-jie;HAN Xin-hui(College of Agronomy,Northwest A&F University,Yangling 712100,China;Shaanxi Engineering Research Center of Circular Agriculture,Yangling 712100,China)

机构地区：[1]西北农林科技大学农学院,杨凌712100 [2]陕西省循环农业工程技术研究中心,杨凌712100

出　　处：《环境科学》2023年第8期4689-4697,共9页Environmental Science

基　　金：陕西省农业科技创新计划项目(NYKJ-2022-YL(XN)16);国家林业和草原局林草科技创新发展与研究项目(2020132111)。

摘　　要：降水作为全球气候变化的关键因子,其变化会影响土壤呼吸.微生物是土壤呼吸的关键驱动因素,但是在不同降雨梯度下,针对脆弱生境地区,微生物化学计量与呼吸的关系还不明确.以黄土丘陵区典型撂荒草地为研究对象开展了原位模拟降雨变化的实验(5个降水梯度),测定了土壤呼吸、养分、微生物生物量和胞外酶,并计算微生物计量特征.结果表明:①土壤呼吸(SR)在增雨处理下土壤呼吸显著升高,而在减雨处理下显著降低.②降水变化影响了化学计量不平衡,其中活性资源库氮(N)与磷(P)之间的不平衡(N∶P不平衡)整体呈现出近“U”型趋势,活性资源库碳(C)与P之间的不平衡(C∶P不平衡)仅在2019年变化显著,变化趋势为:P50>P25>CK>D25>D50,表明C∶P不平衡对降雨变化更敏感.③随降雨量的增加土壤β-1,4-葡糖苷酶(BG)降低,氮降解酶活性β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)和亮氨酸胺肽酶(LAG)之和(NAG+LAP)在两年减雨处理期间显著下降;碱性磷酸酶(ALP)在增雨条件下活性显著增强,而在减雨条件下活性显著减弱;BG∶(NAG+LAP)和BG∶ALP均在增雨条件下显著减少而在减雨条件下显著增强.④偏最小二乘路径模型(PLS-PM)表明,降水变化通过影响化学计量C和P的不平衡和土壤酶的产生改变了土壤呼吸.这些结果突出了降水变化下化学计量不平衡在调节土壤呼吸中的重要性,有助于预测降水变化引起的化学计量变化对陆地生态系统碳循环和养分流动过程的调控.As a key factor of global climate change,precipitation can affect soil respiration.Microorganisms are the key drivers of soil respiration,but the relationship between microbial stoichiometry and respiration in vulnerable habitat areas under different precipitation gradients is unclear.In this study,five precipitation gradients were simulated on a typical abandoned grassland in the loess hilly region.Soil respiration,nutrients,microbial biomass,and extracellular enzymes were measured,and the microbial measurement characteristics were calculated.The results showed that:①soil respiration(SR)increased significantly under rainfed treatment but decreased significantly under D50 treatment.②Precipitation changes affected the stoichiometric imbalance,and the N∶P imbalance of the active resource pool presented a u-shaped trend,whereas the C∶P imbalance changed significantly only in 2019,with a trend of P50>P25>CK>D25>D50.Additionally,the stoichiometric imbalance was caused by the soil stoichiometry.In 2019,the C∶P imbalance of the active resource pool showed a trend of P50>P25>CK>D25>D50,whereas the N∶P imbalance of the active resource pool showed a u-shaped trend,and the stoichiometric imbalance was caused by soil stoichiometry changes.③Soilβ-1,4-glucosidase(BG)enzyme decreased with increasing precipitation,and the sum activities ofβ-1,4-N-acetylglucosaminidase(NAG)and leucine aminopeptidase(LAP)significantly decreased during two years of rainfall reduction treatment.The activity of alkaline phosphatase(ALP)significantly increased under increasing rainfall but significantly decreased under decreasing rainfall.BG∶(NAG+LAP)and BG∶ALP were significantly decreased under increasing precipitation conditions but significantly increased under decreasing precipitation conditions.④The partial least squares path model(PLS-PM)showed that precipitation had an impact on soil respiration through influencing C∶P stoichiometric imbalance and soil enzyme stoichiometric ratio.These results highlight the importance of

关 键 词：撂荒草地 降水变化 土壤呼吸 化学计量不平衡 胞外酶活性 

分 类 号：X171[环境科学与工程—环境科学]