科尔沁沙地两种典型乔灌木耗水特点

Characteristics of soil water consumption of two typical shrub and arbor in Horqin sandy land

以科尔沁沙地典型固沙植物小叶锦鸡儿(Caragana microphylla Lam.5年生)和樟子松(Pinus sylvestris var.mongolica Litrin,7年生)为研究对象,栽植于可渗漏式生长箱,应用TDR水分仪测定生长季节土壤水分变化,依据土壤水分平衡理论推算单位面积植被区的蒸散量。经2a研究,在相同栽植密度下(1m×1m),樟子松植被区土壤贮水量高于小叶锦鸡儿植被区;在不同栽植密度下,小叶锦鸡儿土壤贮水量以1m×2m密度区高于1m×1m密度区。生长季节单位面积土壤蒸散量以小叶锦鸡儿(1m×1m)最高,小叶锦鸡儿(1m×2m)其次,樟子松(1m×1m)最低。单丛/株蒸散量以小叶锦鸡儿(1m×2m)最高,小叶锦鸡儿(1m×1m)其次,樟子松(1m×1m)最低。在试验所涉及的特定年龄阶段,小叶锦鸡儿植被区蒸散耗水量高于樟子松区,土壤水分含量低于樟子松区。生产实践中应根据植物耗水特点选择适宜的固沙物种和栽植方式,以保证人工固沙植被区土壤水分的收支平衡。

Revegetation is one of effective ways to reduce the impacts of desertification. Caragana microphyUa Lam. and Pinus sylvestris var. mongolica Litrin have been widely used to stabilize shifting sand in Horqin sandy land since 1980＇s. However, soil water deterioration has been a major concern in C. microphyUa and P. mongolica plantations, and in many places current soil moisture can＇t meet the demand for plants＇ growth. To determine water budget of the C. microphylla and P. mongolica plantations, we studied the effect of plantations on soil moisture, and assessed the evapotranspiration in C. microphyUa and P. mongolica plantations. Investigation was conducted at a fenced plot at Wulanaodu （119°30′E and west edge of the Horqin sandy land in Inner Mongolia, North China. Plants of 42°29′N, 479m a. s. l）, situated at the C. microphyUa grown for 5 years and P.mongolica grown for 7 years in the plantations were selected, and transplanted to iron boxes （400cm × 200cm ×120cm） which can drain extra water. A plant density 1 m × 1 m was applied to P. mongolica, and two plant densities 1 m × 1 m and 1m ×2m were applied to C. rnicrophylla. The transplanted plants grew for two years in the boxes. Soil moisture from soil surface to depth 80cm were measured at 20cm intervals in boxes every 10 days （2004） or 3 days （2005） during the growing seasons with TDR water menstruation apparatus. The evapotranspiration was estimated according to a mathematical model, and the characteristics of soil water consumption and evapotranspiriation of these two plantations were analyzed. The soil water of P. mongolica was more than that of C. microphylla when the density （ 1 m × 1 m） was same. The soil water of C. rnicrophylla with 1m ×2m density was more than that of 1m ×1m density. The evapotranspiriation ranging from the high to the low was C. rnicrophylla. （ 1m× 1m）, C. rnicrophylla（ 1m ×2m） and P. mongolica （ 1m × 1m） during the growing seasons. The evapotranspiration of individual plant ranging from the high to the low was C. rnicrophylla （ 1 m × 2m） , C. rnicrophylla. （ 1m × 1m）, and P. mongolica （ 1m × 1m） during the growing seasons. C. rnicrophylla grown for 5a consumed more water than P. mongolica grown for 7a when the density was same.