| 摘要: |
| 【目的】分析白榆纯林（BB）、刺槐纯林（CC）及二者不同比例混交林土壤呼吸速率的日变化及月变化特征，探究影响研究区土壤呼吸的主导因子。【方法】利用LI 8100土壤碳通量全自动观测系统，测定陕西杨凌试验田栽植的白榆纯林(BB)、刺槐纯林(CC)及二者不同比例（1∶1（1B1C），1∶2（1B2C）和2∶1（2B1C））混交林5种林型生长季的土壤呼吸速率，并利用观测仪附带的土壤温度探针测定地表及地下5，10和15 cm深处的土壤温度，用土壤湿度传感器测定地下10 cm深处的土壤含水量。【结果】白榆/刺槐不同林型土壤呼吸速率在6，7，9月的日变化均呈单峰曲线，峰值出现在午后12:00－15:00，之后逐渐降低，其中混交林1B2C 7，9月土壤呼吸速率峰值高于其他林型，分别为4.193和4.283 μmol/(m2· s)；白榆/刺槐不同林型土壤呼吸速率均表现出明显的月变化规律，7-9月土壤呼吸速率均较高，在5-9月，5种林型中白榆纯林的土壤呼吸速率一直很低，而混交林1B2C始终较高。土壤温度与土壤呼吸速率的变化基本一致，二者表现出强烈的正相关性，其中地下5 cm 深处土壤温度与土壤呼吸速率的相关性最好。土壤呼吸与土壤含水量之间的关系表现离散，二者相关性不显著。【结论】在不同林型中，白榆纯林的土壤呼吸速率较低，混交林1B2C一直较高；影响该区白榆、刺槐纯林及不同比例混交林土壤呼吸速率的主要因子是地下5 cm深处的土壤温度，而土壤含水量对土壤呼吸速率影响不明显。 |
| 关键词: 白榆 刺槐 混交林 生长季 土壤呼吸速率 |
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| 基金项目:中国科学院战略性先导科技专项（XDA05060300）；国家林业公益性行业科研专项（200904056）；安徽农业大学稳定和引进人才科研资助项目（2010） |
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| Variation characteristics of soil respiration rate in Ulmus pumila Robinia pseudocacia in different forest types during the growing season |
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| Abstract: |
| 【Objective】The study was done to analyze the daily and monthly variation characteristics of soil respiration rate in pure Ulmus pumila forest （BB）,pure Robinia pseudoacacia forest (CC) and U.pumila R.pseudoacacia mixed forests and explore the leading factors affecting soil respiration rate of the study area.【Method】Five kinds of forest types soil respiration rate were measured by LI-8100 soil carbon flux automatic observing system during the growing season of pure U.pumila forest,pure R.pseudoacacia forest and U.pumila R.pseudoacacia mixed forests with different proportions（1∶1 (1B1C),1∶2 (1B2C),and 2∶1 (2B1C)) at Yangling district in Shaanxi Province.And the soil temperature at the surface and 5 cm,10 cm,15 cm underground and the soil moisture content at 10 cm underground were measured by probes with LI-8100 attached at the same time.【Result】The daily variation of soil respiration rate in June,July and September all showed single-peak curve in different types of U.pumila and R.pseudoacacia.The peak time occured between 12:00-15:00 in the afternoon and then the soil respiration rates began to decline gradually.The peak value of soil respiration rate of 1B2C in mixed forest was higher than other forest types in July (4.193 μmol/(m2·s)) and September (4.283 μmol/(m2·s)).The soil respiration rate showed significant monthly variation and the maximum rate appeared from July to September.From May to September,the soil respiration rate of pure U.pumila forest was lower and the mixed forest of 1B2C was higher in the five different forest types.Soil respiration rate varied similarly to soil temperature and they showed a strong positive correlation between them,especially with soil temperature at 5 cm depth.Soil respiration rate and the relationship between soil water content of discrete performance and the relevance between them were not notable.【Conclusion】The soil respiration rate of pure U.pumila forest was lower and the mixed forest of 1B2C was higher in different forest types.The main factor affecting the soil respiration rate of pure U.pumila forest,pure R.pseudoacacia forest and U.pumila R.pseudoacacia mixed forests was soil temperature at 5 cm depth in the district and the relevance between soil respiration rate and soil moisture content was not notable. |
| Key words: Ulmus pumila Robinia pseudoacacia mixed forests growing season soil respiration rate |
