摘要
在宁夏盐池沙质草地生境中,模拟夏季(7~8月)增雨试验,设置0%(即对照不增雨)、增雨20%、40%、60%、100%梯度处理样地,通过测定2012~2013年每个处理样地土壤温度与土壤水分,分析了夏季降雨变化对沙质草地土壤温度分布的影响。结果表明,研究区域样地土壤温度日变化呈正弦曲线变化,这种日变化格局包括变异系数和振幅受夏季增雨处理的影响较小,但不同增雨处理样地土壤温度日变化的位相不同,随季节变化均呈现出不同程度的位相提前。从季节分布上看,20%(或60%)增雨处理提高(或降低)土壤温度,而其受季节改变的影响较小,但40%和100%增雨处理样地对土壤温度的影响依赖于季节变化。夏季土壤温度的年际变化受到增雨处理的后续影响较大,而秋季土壤温度的年际变化受到的影响较小。研究表明,沙质草地土壤温度受到夏季降雨量变化的后续影响存在一个降雨量阈值水平,并且在不同季节其影响程度不同。
A simulation experiment for the increments of 0%, 20%, 40%, 60%, 100% summer rainfall was set up in the sandy grassland of Yanchi in Ningxia province. Soil temperature, together with soil moisture, was measured from2012 to 2013 in order to probe into the effects of summer rainfall change on soil temperature in the sandy grassland ecosystem. It was found that the daily changes of soil temperature tended to be as a sine curve, and it's CV and amplitude were not affected by summer rainfall but dependent on the seasonal variation. The phase of daily changes of soil temperature was affected by summer rainfall amount and dependent on the seasonal timing. Seasonally, 20% and60% increases of summer rainfall indicated a contrasting(i.e., the former to increase and the latter to decrease) effect on soil temperature, which was independent on seasonal timing. Whereas, the effects of 40% and 100% increases of summer rainfall were found to depend on the seasonal timing. From 2012 to 2013, the summer soil temperatures(e.g.,July and August) were affected remarkably by the summer rainfall increases, whereas the autumn soil temperatures(e.g., September and October) were affected little. It was suggested that the impacts of summer rainfall changes on soil temperature depended much on a threshold of rainfall amount, and also to some extent depended on the seasonal timing changes in the sandy grassland ecosystem.
出处
《土壤通报》
CAS
CSCD
北大核心
2015年第2期348-354,共7页
Chinese Journal of Soil Science
基金
国家自然科学基金项目(41101050)
高校博士学科点基金专项(20126401110003)
中国科学院沙漠与沙漠化重点实验室开放基金项目(KLDD-2014-003)
国家留学基金委与巴伊兰大学联合奖学金项目资助
关键词
沙质草地
降雨量
土壤水分
土壤温度
气候变化
Sandy grassland
Rainfall changes
Soil moisture
Soil temperature
Climate changes
