川中丘陵区不同植被类型土壤理化性质及水文效应

Physical and chemical properties of soil and the hydrological effects of different vegetation types in the central Sichuan hilly region

为揭示紫色土区不同植被类型土壤理化性质和水文效应空间分布特征,测定官司河流域紫色土区柏木麻栎混交林(Cupressus funebris,Quercus acutissima)、柏木纯林、方竹林(Chimonobambusa quadrangularis)和农地4种植被类型土壤理化性质、土壤孔隙状况及水文特征.结果表明:(1)土壤有机碳含量表现为柏木麻栎混交林>方竹林>柏木纯林>农地.柏木麻栎混交林土壤有机碳(18.04 g/kg)、全氮(1.51 g/kg)、全磷(1.49 g/kg)、全钾(53.1 g/kg)、速效氮(81.69 mg/kg)、速效磷(2.14 mg/kg)积累作用最好.(2)不同植被类型土壤容重均值表现为农地>柏木纯林>柏木麻栎混交林>方竹林,随土层加深,4种植被类型容重变化规律不同,其中农地增加幅度最大,为9.34%.(3)0-100 cm土层自然含水量、毛管持水量、最大持水量、含蓄降水量均表现为柏木麻栎混交林最高,田间持水量表现为农地最高.随着土层加深,不同植被类型水文效应规律变化差异较大.综上所述,不同植被类型不同土层深度土壤理化性质和水文效应特征差异显著,柏木麻栎混交林较柏木纯林更适宜在研究区推广种植,方竹林对该区土壤状况适应性较好,结果可为川中丘陵区紫色土人工林经营管理、生态环境恢复及水源涵养功能评价提供理论依据.

To investigate the spatial distribution characteristics of the physical and chemical properties of soil and the hydrological effects of different vegetation types in the purple-soil area, the soil organic carbon content, bulk density, porosity, and water storage in different vegetation types and at different depths of four vegetation types (Cupressus funebris-Quercus acutissima, Cupressus funebris, Chimonobambusa quadrangularis, and farmland) in the central Sichuan hilly region were measured. The results showed that:(1) the average organic carbon content of the four vegetation types in 0-20 cm soil layer was as follows: C. funebris-Q. acutissima > C. quadrangularis > C. funebris > farmland. The organic carbon content (18.04 g/kg), total nitrogen content (1.51 g/kg), total phosphorus content (1.49 g/kg), total potassium (53.1 g/kg), available nitrogen (81.69 mg/kg), and available phosphorus (2.14 mg/kg) of C. funebris-Q. acutissima mixed forests soil was the best.(2) The mean soil bulk density of different forest types was shown as farmland > C. funebris > Cupressus-Quercus > C. quadrangularis, which varied with the deepening of soil layer. Among these, farmland showed the largest increase (9.34%).(3) In the Cupressus-Quercus mixed forest soil, the natural water content, capillary water holding capacity, maximum water holding capacity, and the implied precipitation in the 0-100 cm soil layer were the highest. The field water holding capacity of farmland was the highest. Thus, different types of hydrological effects varied greatly as the soil layer deepened, Cupressus-Quercus mixed forest was more suitable for planting in a research area than pure cypress wood forest, and the bamboo forest had good adaptability to the soil conditions in this area. The results can provide a theoretical basis for the management, restoration of the ecological environment, and evaluation of the water conservation function of the artificial forest under different stands in the purple-soil area of the hilly region of central Sichuan.