杉木取代阔叶林后林下水源涵养功能差异评价

为研究杉木人工林取代常绿落叶阔叶混交林后土壤水源涵养能力的变化,采用室内浸水法和环刀法分别研究杉木纯林和常绿落叶阔叶混交林的枯落物与土壤的持水特性。结果表明:(1)枯落物平均蓄积量表现为常绿落叶阔叶混交林(3.42 t/hm~2)杉木纯林(3.12 t/hm~2),枯落物平均厚度表现为杉木纯林(9.17 cm)常绿落叶阔叶混交林(5.42 cm)。(2)最大持水量表现为常绿落叶阔叶混交林(6.23 t/hm~2)杉木纯林(5.57 t/hm~2),最大持水率也表现出相同的规律,即常绿落叶阔叶混交林(184.40%)杉木纯林(179.50%);有效拦蓄量表现为常绿落叶阔叶混交林(4.48 t/hm~2)杉木纯林(4.13 t/hm~2),最大拦蓄量表现为常绿落叶阔叶混交林(5.41 t/hm~2)杉木纯林(4.97 t/hm~2)。(3)枯落物层的吸水量与浸水时间符合对数函数Q=aln(t)+b,而吸水速率与浸水时间符合指数函数V=at~b,常绿落叶阔叶混交林的蓄水能力强于杉木纯林。(4)土壤水分最大吸持贮水量表现为常绿落叶阔叶混交林(43.58 mm)杉木纯林(41.88 mm),可以看出常绿落叶阔叶混交林内的土壤可以更好地为植被提供良好的水分供其生长;土壤水分最大滞留贮存量表现为常绿落叶阔叶混交林(8.20 mm)杉木纯林(10.22 mm),即杉木纯林内的土壤具有更好的涵养水源能力。从枯落物最大持水量、有效拦蓄量以及土壤毛管孔隙度、非毛管孔隙度等多个因素的计算综合推断可知,杉木人工林水源涵养能力优于常绿落叶阔叶混交林。

Evaluation on the Difference of Understory Water Conservation Function After Chinese Fir Replacing Broad-leaved Forest

In order to study the changes of soil water conservation ability after replacing evergreen deciduous broad-leaved mixed forest with Chinese fir plantation, the water retention characteristics of the litter and soil in the above two stands were studied by the indoor soaking method and the cutting ring method, respectively. The results showed that:(1) The average volume of litter in the evergreen deciduous broad-leaved mixed forest (3.42 t/hm²) was higher than that in the Chinese fir plantation (3.12 t/hm²), and the average litter thickness was Chinese fir forest (9.17 cm)>evergreen deciduous broad-leaved mixed forest (5.42 cm). (2) The maximum water-holding capacity was evergreen deciduous broad-leaved mixed forest (6.23 t/hm²)>Chinese fir forest (5.57 t/hm²), and the maximum water holding rate also showed the same rule, that was, evergreen deciduous broad-leaved mixed forest (184.40%)>Chinese fir forest(179.50%). The effective interception amount and the maximum amount of interception were both evergreen deciduous broad-leaved mixed forest (4.48 t/hm² and 5.41 t/hm²)>Chinese fir forest (4.13 t/hm² and 4.97 t/hm²). (3) The water absorption amount and soaking time of litter layer accorded with logarithmic function Q=aln(t)+b, while the water absorption rate and soaking time accorded with exponential function V=at^b, the water storage capacity of evergreen deciduous broad-leaved mixed forest was stronger than that of Chinese fir forest. (4) The maximum soil water holding capacity of evergreen deciduous broad-leaved mixed forest (43.58 mm) was higher than that of Chinese fir forest (41.88 mm), the soil in evergreen deciduous broad-leaved mixed forest could provide better water support for vegetation growth. The maximum retention of soil moisture was evergreen deciduous broad-leaved mixed forest (8.20 mm)