辽西低山丘陵区人工油松林和沙棘林的水文生态效应

Hydro-ecological effects of artificial Pinus tabulaeformis carr.and Hippophae rhamnoides stands in low mountainous upland of western Liaoning Province,China

利用设置在不同地类内的径流小区,对辽西大凌河流域的沟壑丘陵区进行定位观察,探讨辽西半干旱区主要造林树种油松和沙棘的水文生态效应.结果表明：2002年6月～2004年6月平均降水量为238.9mm时,油松和沙棘平均林冠截留量分别为55.5mm和76.05mm,其截留率分别为23.08%和32.28%,即约有1/4～1/3降水被林冠截留.油松林中凋落物平均截留率为14.17%,沙棘林为20.8%.油松林和沙棘林年均径流深分别为2.516mm和0.893mm;侵蚀量为15.57t km^-2和0.76t km^-2;林地内径流深和侵蚀量约为荒地（对照）的1/20和1/50.林地土壤理化性质,除土壤容重之外,0～20cm土层的总孔隙度、非毛管孔隙度、饱和含水量和非毛管持水量都高于2～40cm土层;油松林和沙棘林土壤有机质、全氮、全钾和速效钾含量均显著高于荒地;pH、全磷和速效磷在地类和不同土层深度中没有显著差异.沙棘林和油松林的非毛管持水量分别是荒地的275.9%和182.1%.

Pinus tabulaeformis carr. and Hippophae rhamnoides are widely planted in the low mountainous upland and loess plateau, and are main species for afforestation in the semiarid region. In order to expound their roles in controlling serious soil and water loss and the mechanism of role, a study on the hydro-ecological effects of the stands was carried out in the period from 2002 to 2004, using the method of runoff plot set up in different stands and soil physical and chemical analyses. The experimental stands are located in the low mountainous upland of western Liaoning Province, where the annual average air temperature is 5.4 - 8.7℃, the annual precipitation is 450 - 580mm, of which in June averages 238.9mm, the annual average humidity is 38 % ～ 82 % . Vegetation cover is 28 % of entire land area. The age of Pinus tabulaeformis Carr. stand is 28 year old, and its density is 2825 tree/hm^2, and forest crown coverage is 0.75; while those Hippophae rhamnoides stand is 11 year old, 8950 tree/hm^2, 0.90, respectively. The results showed that the intercepting rates of canopy in Pinus tabulaeformis carr. and Hippophae rhamnoides stand were 23.08% and 32.28%. The litter intercepting rate averaged 14.17% in Pinus tabulaeformis carr. and 20.8% in Hippophae rhamnoides stands, respectively. The runoff depths were 2.516mm and 0.893mm in Pinus tabulaeformis carr. and Hippophae rhamnoides stands while erosion amounts 15.57 t km^-2 and 0.76 t km^-2, respectively. Under the comprehensive action of the artificial stands, the runoff depth and erosion amount from woodland were, respectively, 1/20 and 1/50 of that from wasteland, which indicated the great hydro-ecological functions of Pinus tabulaeformis carr. and Hippophae rhamnoides forests. Litter and died roots may be decomposed into organic matter and nutrient substances with the help of microbe; thus will be distinctly improved the physical and chemical properties of its soil after death. In comparison with wasteland, the bulk density of soil decreased in woodland, while the content of organic matter, total N, total K and available K significantly increased. The physical properties of soil in woodland, such as total porosity, non-capillary porosity, saturated moisture content, non-capillary water-holding capacity etc., were distinctly higher in surface soil （0 - 20 cm） than those of soil at the depth of 20 - 40 cm. There was no significant difference in pH,total P and available P among different land types or different soil depth. The non-capillary water-holding capacities in Pinus tabulaeformis carr. and Hippophae rhamnoides stands were 182.1% and 275.9% times in wasteland, respectively.