覆盖经营雷竹林的土壤热通量季节变化特征

Seasonal changes in soil heat flux for a Lei bamboo forest with straw mulching

2010年10月至2011年9月,运用土壤热通量板和常规气象观测仪器对浙江省临安市太湖源镇覆盖经营的雷竹Phyllostachys violascens林土壤热通量和气象因子进行了观测研究。结果表明：在月尺度上5 cm土壤热通量日变化均成＂S＂形,但月均值差异明显（P〈0.05）。年尺度土壤是热源,净年热通量为-20.01 MJ.m-2,土壤月均值热通量占月净辐射的-6.2%~3.5%,年总值为净辐射的-0.67%。分析地温、净辐射因素与土壤热通量的关系,土壤热通量与5 cm,50 cm和100 cm土壤温度月均值回归研究表明：与5 cm相关性最显著,说明土壤温度变化是以热通量变化为基础的。土壤热通量月均值与净辐射显著相关（P〈0.05）。覆盖的雷竹林12-3月土壤为热源,土壤热通量负向数值减小,说明覆盖物减少了土壤能量辐射。

The soil heat flux and meteorological factors of a Lei bamboo（Phyllostachys violascens） forest with straw mulching in Taihuyuan,Lin’an City,Zhejiang Prvince from October 2010 to September 2011 were measured.A regression analysis between heat flux and average monthly soil temperature and between monthly soil heat flux and net radiation was conducted for depths of 5,50 and 100 cm,using soil heat flux plates（SHFP） and a meteorological monitoring system.Results indicated that for a depth of 5 cm,diurnal change in the soil heat flux on a monthly basis showed as an ＂S＂ curve.The soil acted as a heat resource with an annual net heat flux of-20.01 MJ·m-2.The average monthly soil heat flux was from-6.2% to 3.5% of the net monthly radiation with the annual average monthly soil heat flux accounting for-0.67% of the net monthly radiation. The regression showed that soil heat flux was significantly（P＆lt;0.05） related to temperature at the 5 cm depth. Also,there was a significant relationship between average monthly soil heat flux and net radiation（P＆lt; 0.05）.From December to the following March in the Lei bamboo forest,soil with straw mulching was a heat source,and the negative values of soil heat flux were reduced.Thus,the regression revealed that changes in soil temperature were based on changes of soil heat fluxes,and with straw mulching radiant/light energy of the soil was reduced.