粤北不同林龄杉木人工林下土壤层及枯落物层持水能力研究

Study on Water-holding Capacity of Soil Layer and Litter Layer of Chinese Fir Plantations with Different Stand Ages in Northern Guangdong

【目的】为了研究粤北地区不同林龄杉木人工林土壤层及枯落物层水源涵养能力情况,并对粤北杉木人工林质量提升和生态改善提供依据。【方法】以广东韶关市3个林场中的杉木幼龄林(7～8年)、中龄林(16～18年)、近熟林(23～25年)为试验对象,采用环刀浸泡法和室内浸泡法对其林下土壤及枯落物持水能力进行比较。【结果】0～30 cm土层土壤容重大小表现为幼龄林(1.22 g/cm^3)>中龄林(1.17 g/cm^3)>近熟林(1.14 g/cm^3),毛管孔隙度大小表现为幼龄林(39.66%)>中龄林(34.04%)>近熟林(32.93%),土壤有效持水量大小表现为幼龄林(650.70 t/hm^2)>近熟林(627.60 t/hm^2)>中龄林(619.78 t/hm^2),但差异均不显著。枯落物有效拦蓄量大小为中龄林(11.01 t/hm^2)>近熟林(10.95 t/hm^2)>幼龄林(4.04 t/hm^2),且中龄林显著高于幼龄林。回归分析表明枯落物在浸水0.5 h内吸水速率最大,其后迅速降低,至12 h时持水量达到稳定;枯落物持水量与浸泡时间成对数关系(R^2> 0.92),其吸水速率与浸泡时间成幂函数关系(R^2> 0.97),且吸水速率均表现为近熟林>中龄林>幼龄林。【结论】不同林龄杉木人工林土壤层持水能力表现为幼龄林>近熟林>中龄林,枯落物层持水能力表现为近熟林>中龄林>幼龄林。

[Objective]To study the water-holding capacity of soil layer and litter layer of Chinese fir(Cunninghamia lanceolata) plantations with different ages in northern Guangdong, and to provide basis for improving the quality and ecology of Chinese fir Plantations in northern Guangdong.[Method]The young Chinese fir plantations(7-8 years),middle-aged Chinese fir plantations(16-18 years) and near-mature Chinese fir plantations(23-25 years) in three forest farms in Shaoguan City, Guangdong Province were used for study, and the ring knife soaking method and indoor soaking method were applied in the comparative study of the water-holding capacity of soil layer and litter layer. [Result]In soil layer of 0~30 cm, the soil bulk density of young Chinese fir plantations(1.22 g/cm^3) was the highest, followed by middleaged Chinese fir plantations(1.17 g/cm^3) and near-mature Chinese fir plantations(1.14 g/cm^3);the capillary porosity of young Chinese fir plantations was the largest(39.66%), followed by middle-aged Chinese fir plantations(34.04%) and nearmature Chinese fir plantations(32.93%);the effective water holding capacity of young Chinese fir plantations was the largest(650.70 t/hm^2), followed by near-mature Chinese fir plantations(627.60 t/hm^2) and middle-aged Chinese fir plantations(524.40 t/hm^2), but the difference in the above the aspects was not significant. The effective litter storage capacity of middleaged Chinese fir plantations was the largest(11.01 t/hm^2), followed by near-mature Chinese fir plantations(10.95 t/hm^2) and young Chinese fir plantations(4.04 t/hm^2), and the capacity of middle-aged Chinese fir plantations was significantly higher than that of the two. Regression analysis showed that the litter had the highest water absorption rate within 0.5 h after water soaking, then the rate decreased rapidly, and the water-holding capacity became stable at 12 h after water soaking. The water-holding capacity of litter was logarithmically related to the soaking time(R^2 > 0.92), and the water absorption rate was in a power function relationship with the soaking time(R^2 > 0.97), and the water absorption rate of near-mature Chinese fir plantations was the highest, followed by middle-aged Chinese fir plantations and young Chinese fir plantations.[Conclusion]The soil water-holding capacity of soil layer of Chinese fir plantations with different forest ages is as follows: young Chinese fir plantations had the largest capacity, followed by near-mature Chinese fir plantations and middle-aged Chinese fir plantations;as to the water-holding capacity of litter layer, the near-mature Chinese fir plantations had the largest, followed by middle-aged Chinese fir plantations and young Chinese fir plantations.