岷江上游花椒地/林地边界土壤水分分布及影响域

在岷江上游干旱河谷区选取典型的花椒地,林地边界,利用TDR仪测定干旱条件下和雨后0-15cm表土层水分体积分数,刻画沿样带梯度土壤水分分布以及不同时段土壤水分变化,同时用移动窗口法判定土壤水分的边界影响域。结果表明,在干旱河谷区土壤水分体积分数较低并沿样带存在明显的变化,从林地到边界到花椒地土壤水分体积分数基本呈“V”字型变化;而在林地和花椒地内部,水分体积分数呈“W”型波动。干旱时土壤水分体积分数日间变化不大,而雨后水分体积分数逐日递减。土壤水分的影响域在雨后可达14m,干旱时为8m。

Distribution and depth of edge influence on surface soil moisture in field-forest boundary in arid valley of upper reaches of Minjiang River

To study distribution and depth of edge influence on surface soil moisture in field-forest boundary in arid valley of upper reaches of Minjiang River, typical pepper-forest boundary was selected in arid valley of upper reaches of Minjiang River, China. Moisture content in 0-15 cm surface soil was determined with time domain reflecmentory (TDR) during drought and after rain. The aims were to describe soil moisture distribution along transect gradient and the variety in pepper field and forest. And moving split-window techniques (MSWT) was employed to determine the depth of edge influence. The results show: surface soil moisture content was lower and exhibited a high degree of variability along transect gradient. It displayed the change of "V" figure from forest to boundary and to pepper field, but the fluctuation of "W" wave in interior forest and interior pepper field. The variability of moisture content was less between days during drought, but it descended after rain day by day. The depth of edge influence on moisture content was 14 m and 8 m after rain and during drought, respectively.