安吉毛竹林生态系统水分收支的研究

利用涡度相关技术观测安吉毛竹林生态系统2013年的水汽通量,同时结合降雨量对该生态系统的水分收支数据进行比较和分析,明确其水收支情况及其影响因子,以揭示毛竹林的水分利用能力,进而为其科学栽培和水分管理提供参考.结果显示:毛竹林生态系统全年表现为水汽源,7月份最高(108.85kg·m~(-2)),12月份最低(19.67kg·m~(-2)),但在2月份和6月份存在着小的波谷.全年降水量和蒸散量呈较弱的正相关关系(r=0.145,p0.05),蒸散主要集中于5—8月份,7月份最大,达到108.85mm,而降水较为分散,6月份有最大值,为394.5mm,且全年除了1、7和11月份的蒸散量略高于降水量外,其余各月均较低;不同季节的降雨量从高到低依次为:夏季秋季春季冬季,而蒸散量(水汽通量)则表现为:夏季春季秋季冬季.此外,全年水汽通量受温度的影响较为显著(p0.05),7月份则受温度和饱和水汽压差的双重影响.总之,2013年全年降雨总量达到1 508.5mm,蒸散量为749.07mm,蒸散量占到降水总量的49.7%,全年水分利用效率仅2.1g·kg-1,表明该毛竹林的地表径流较大,水分利用能力偏弱,若进行人工经营和管理,除了考虑环境因子变化外,还须注意合理用水,以避免水资源的浪费.

Study on the water budget of Phyllostachys edulis forest ecosystem in Anji,Zhejiang

To definitize the water budget and its factors of Phyllostachys edulis forest ecosystem in Anji County, Zhejiang Province in 2013, and then reveal the water use ability, further provide theoretical guide for scientific cultivation and water management, the eddy covariance observation technology was used to obtain water vapor fluxes data, and the rain gauges were used to gain precipitation data for water budget in this ecosystem.The results showed that in 2013, Phyllostachys edulis forest ecosystem was water vapor source for the atmosphere, the maximum value was in July (108.85 kg·m-2), and the minimum was in December (19.67 kg·m-2).But there were small troughs in February and June.In addition, it showed a weak positive correlation between precipitation and evapotranspiration (r = 0.145, p＞0.05).The evapotranspirations were focused mainly in May to August, and the maximum (108.85 mm) was in July.On the contrary, the precipitations were scattered, the maximum was 394.5 mm in June.Except for January, July and November, the precipitations were more.For different seasons, the precipitations were ordered as summer＞autumn＞spring＞winter, but the variation of the evapotranspirations (water vapor fluxes) was summer＞spring＞autumn＞winter.What's more, water vapor flux in the whole year was affected by air temperature (Ta) significantly (p＜0.05), and that in July was influenced by both Ta and VPD.In a word, the total precipitation is 1 508.5 mm, the evapotranspiration is 749.07 mm, the evapotranspiration accounts for 49.7% of the total precipitation, and the water use efficiency is 2.1 g·kg-1, which suggests that the runoff of Phyllostachys edulis forest is larger, and the water use ability is relatively weaker.So more attention must be paid to follow reasonable irrigation to avoid wasting water beside environmental factors.