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敦煌市葡萄园土壤呼吸及其组分变化
张扬, 朱高峰, 赵楠, 秦文华, 陈惠玲
兰州大学 资源环境学院, 西部环境教育部重点实验室, 甘肃兰州 730000
摘要:
[目的] 分析西北干旱区葡萄园土壤呼吸及其组分变化特征,同时探究其与土壤温湿度的关系,为西北干旱区的土壤碳排放估算及其特色农业发展提供一定的参考。[方法] 于2019年6-12月采用LI-8100 A土壤呼吸测量系统和自动气象站观测甘肃省敦煌市南湖绿洲葡萄园的土壤呼吸及环境因子,通过根排除法区分土壤呼吸组分。[结果] ①观测期内,葡萄园的土壤呼吸速率在7月3日达到最大。在生长季的6-9月,土壤呼吸速率波动变化明显;而非生长季的10-12月,土壤呼吸速率逐渐减小。该区土壤呼吸以异养呼吸为主,平均异养呼吸贡献率约为65%。②在小时尺度上,土壤呼吸及其异养组分与土壤温度由于时间滞后效应均呈回环关系。而在日尺度上,非生长季的10-12月,土壤呼吸、异养呼吸随土壤温度的增加呈指数增加趋势;但生长季的6-9月,灌溉和较大降雨会引起土壤含水率波动进而干扰上述指数响应。③生长季的6-9月,土壤呼吸及其组分与土壤含水率具有二次函数关系,土壤呼吸的最适含水率约为8.1%~9.9%;而非生长季10-12月则呈指数关系,二者关系差异主要是由于非生长季的10-12月土壤含水率下降的同时土壤温度也在持续降低,且葡萄埋土冬藏,造成异养、自养呼吸均迅速降到低值,然后处于稳定状态所致。[结论] 土壤呼吸受到土壤温湿度的综合调控,其双因子模型可以较好地解释非生长季的土壤呼吸变化,但在生长季仅能解释土壤呼吸变化的32%,因此应进一步建立生长季土壤呼吸的多因子模型以便更好地模拟生长季土壤呼吸的变化。
关键词:  葡萄园  土壤呼吸  土壤温度  土壤含水率
DOI:10.13961/j.cnki.stbctb.2021.01.011
分类号:S154.4
基金项目:国家自然基金面上项目”极端干旱绿洲农田生态系统土壤—植被—大气连续体水分传输机制与模拟研究”(41871078);国家重点研发计划项目“环盆山地云水资源高效利用与水源涵养功能提升技术”(2018YFC0406602)
Soil Respiration and Its Components at Vineyard in Dunhuang City
Zhang Yang, Zhu Gaofeng, Zhao Nan, Qin Wenhua, Chen Huiling
MOE Key Laboratory of Western China's Environmental Systems, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, Gansu 730000, China
Abstract:
[Objective] The variation in soil respiration and its components in a vineyard in an arid area in Northwest China were analyzed and the relationship between soil temperature, soil water content, and soil respiration was studied in order to provide some reference for the estimation of soil carbon emission and the development of featured agriculture in arid areas of Northwest China.[Methods] Soil respiration and environmental parameters of a vineyard at South Lake oasis of Dunhuang City, Gansu Province were observed using an LI-8 100 A soil respiration measurement system and automatic meteorological station from June to December 2019, and soil respiration components were distinguished by root exclusion methods.[Results] ① During the observation period, the soil respiration rate in the vineyard reached its maximum on July 3. The soil respiration rate fluctuated significantly from June to September during the growing season, while it decreased gradually from October to December during the non-growing season. Heterotrophic respiration was the main component in this area, and the average contribution rate of heterotrophic respiration was approximately 65%. ② On an hourly scale, the relationship of hysteresis loops between soil respiration, heterotrophic respiration, and soil temperature was obvious because of the time lag effect. On a daily scale, soil respiration and heterotrophic respiration increased exponentially with the increase in soil temperature during the non-growing season (from October to December). However, irrigation and heavy rainfall could cause fluctuations in soil water content, interfering with the above exponential responses during the growing season (from June to September). ③ During the growing season (from June to September), soil respiration and its components had a quadratic function relationship. The optimal soil water content was approximately in the range of 8.1% to 9.9%. However, there was an exponential relationship from October to December during the non-growing season. The difference was mainly caused by the decrease in soil water content and soil temperature during the non-growing season. The vine branches were buried underground, which caused the heterotrophic and autotrophic respiration to decrease rapidly to a low value and then remain stable.[Conclusion] Soil respiration was regulated by soil temperature and soil water content. The two-factor model could explain the variation in soil respiration well during the non-growing season, but it only explained 32% of the variation during the growing season. Therefore, the multifactor model of soil respiration during the growing season should be further established to better simulate the variation during the growing season.
Key words:  vineyard farm  soil respiration and its components  soil temperature  soil water content