降水量对半干旱沙质草地土壤胞外酶活性的影响

doi:10.7522/j.issn.1000-694X.2025.00069

摘要/Abstract

摘要：

土壤酶深度参与土壤系统的养分循环进程，是维系植物与土壤养分关联的核心纽带。土壤胞外酶活性对降水格局的变动极为敏感，在缺水且养分匮乏的沙质草地生态系统中尤为突出。本研究以半干旱沙质草地为研究对象，开展不同降水条件下土壤胞外酶活性变化研究，确定沙质草地生态系统土壤胞外酶活性动态变化规律，揭示沙质草地土壤碳、氮、磷含量以及酶活性对短期降水变化的响应机制。结果显示：（1）减少30%降水条件下的植物地上生物量比自然条件显著降低（P<0.05），而土壤容重和电导率比自然条件下显著增加（P<0.05）；（2）相较于对照组，增加60%降水处理使微生物碳限制程度以及微生物氮限制程度显著提高（P<0.05）；（3）土壤胞外酶活性对水分波动响应较强，增加60%降水条件下纤维二糖水解酶活性提高到对照组的2.47倍，对应碳相关酶活性增加19.7%；而氮相关酶活性在对照组表现最大。

关键词: 降水变化, 土壤酶活性, 沙质草地, 植物生物量, 土壤理化性质

Abstract:

Soil enzymes are deeply involved in the nutrient cycling process within the soil system and serve as a core link connecting plant and soil nutrients. The activity of soil extracellular enzymes is extremely sensitive to changes in precipitation patterns， especially in water-scarce and nutrient-poor sandy grassland ecosystems. This study was carried out in semi-arid sandy grasslands to investigate the changes in soil extracellular enzyme activities under different precipitation conditions. The study determined the dynamic variation patterns of soil extracellular enzyme activities in the sandy grassland ecosystem and revealed the response mechanisms of soil carbon， nitrogen， and phosphorus contents as well as enzyme activities in sandy grasslands to short-term precipitation changes. The results show that：（1） Under the condition of 30% reduced precipitation， plant above-ground biomass was significantly lower than that under natural conditions （P<0.05）， while soil bulk density and electrical conductivity were significantly higher than those under natural conditions （P<0.05）；（2） Compared with the control group， the increase of 60% precipitation significantly enhanced the limitation of microbial carbon and nitrogen （P<0.05）；（3） Soil extracellular enzyme activity was highly responsive to changes in water availability. Under the condition of 60% increased precipitation， the activity of cellobiohydrolase increased to 2.47 times that of the control group， and the corresponding carbon-related enzyme activity increased by 19.7%. In contrast， nitrogen-related enzyme activity was optimal in the control group.

Key words: precipitation change, soil enzyme activity, sandy grassland, plant biomass, physical and chemical properties of soil

中图分类号:

景家琪, 刘新平, 何玉惠, 丰洁, 胡鸿姣, 徐远志, 张尧. 降水量对半干旱沙质草地土壤胞外酶活性的影响[J]. 中国沙漠, 2025, 45(4): 368-377.

Jiaqi Jing, Xinping Liu, Yuhui He, Jie Feng, Hongjiao Hu, Yuanzhi Xu, Yao Zhang. Influence of precipitation on soil enzyme activity in sandy grasslands[J]. Journal of Desert Research, 2025, 45(4): 368-377.

图/表 7

表1 降水变化对土壤理化性质的影响

Table 1 Effect of precipitation change on soil physical and chemical index

土壤理化指标	处理
土壤理化指标	P+60%	P+30%	CK	P-30%	P-60%
容重BD/(g·cm⁻¹)	1.533±0.026^ab	1.569±0.018^ab	1.503±0.020^a	1.587±0.017^b	1.540±0.010^ab
酸碱度pH值	7.276±0.072^a	7.208±0.091^a	7.146±0.030^a	7.214±0.051^a	7.340±0.089^a
电导率EC/(S·m⁻¹)	28.20±0.819^a	27.16±1.951^a	27.00±0.804^a	36.60±2.888^b	33.22±2.659^ab
全碳TC/(g·kg⁻¹)	0.276±0.043^a	0.191±0.034^a	0.249±0.047^a	0.295±0.049^a	0.258±0.039^a
全氮TN/(g·kg⁻¹)	0.033±0.008^a	0.025±0.004^a	0.032±0.005^a	0.030±0.003^a	0.037±0.009^a
全磷TP/(g·kg⁻¹)	0.024±0.001^a	0.023±0.001^a	0.025±0.003^a	0.026±0.003^a	0.026±0.003^a
土壤碳氮比C∶N	13.199±5.563^a	7.920±1.740^a	7.685±0.860^a	10.342±1.718^a	8.555±1.671^a
土壤碳磷比C∶P	11.416±1.607^a	8.135±1.290^a	10.738±2.683^a	11.273±1.478^a	9.951±1.607^a
土壤氮磷比N∶P	1.362±0.343^a	1.080±0.122^a	1.382±0.319^a	1.197±0.212^a	1.379±0.366^a

图1 降水变化对植物地上及地下生物量的影响注：CK为自然降水对照组；P+60%、P+30%、P-30%和P-60%分别代表增加自然降水的60%、增加自然降水的30%、减少自然降水的30%以及减少自然降水的60%

Fig.1 Effect of precipitation change on aboveground and underground biomass of plants

图2 不同降水处理下土壤酶活性注：CK为自然降水对照组；P+60%、P+30%、P-30%和P-60%分别代表增加自然降水的60%、增加自然降水的30%、减少自然降水的30%以及减少自然降水的60%

Fig.2 Soil enzyme activities under different precipitation treatments

图3 不同降水处理下土壤酶化学计量比特征注：CK为自然降水对照组；P+60%、P+30%、P-30%和P-60%分别代表增加自然降水的60%、增加自然降水的30%、减少自然降水的30%以及减少自然降水的60%

Fig.3 Characteristics of soil enzyme stoichiometry under different precipitation treatments

图4 不同降水处理下土壤微生物碳氮磷限制注：CK为自然降水对照组；P+60%、P+30%、P-30%和P-60%分别代表增加自然降水的60%、增加自然降水的30%、减少自然降水的30%以及减少自然降水的60%；BG为β葡萄糖苷酶；CBH为纤维二糖水解酶；NAG为β-N-乙酰氨基葡萄糖苷酶；LAP为亮氨酸氨基肽酶；ALP为碱性磷酸酶

Fig.4 limitation of soil microbial carbon， nitrogen and phosphorus under different precipitation treatments

图5 降水变化下土壤理化性质-植被特征-土壤酶活性的相互关系注：CK为自然降水对照组；P+60%、P+30%、P-30%和P-60%分别代表增加自然降水的60%、增加自然降水的30%、减少自然降水的30%以及减少自然降水的60%；NAG为β-N-乙酰氨基葡萄糖苷酶；CE为碳相关酶；CBH为纤维二糖水解酶；ALP为碱性磷酸酶；SWC为土壤含水量；SEC为土壤电导率；VA为酶化学计量的矢量夹角；BGB为地上生物量；TN为全碳

Fig.5 Relationship between soil physical and chemical properties， vegetation characteristics and soil enzyme activities under precipitation change

图6 降水对土壤酶活性的结构方程模型注：PRE为降水量；SWC为土壤含水量；BGB为地上生物量；SEC为土壤电导率；PE为磷相关酶活性；VL为酶化学计量的矢量长度；VA为矢量夹角

Fig.6 Structural equation model of precipitation on soil enzyme activity

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