The Effect Of Soil Water Preserving Technique On Young Plantation In Mountain Forests-Dry Valley Ecotones In The Upper Reach Of Minjiang River

Due to the nature factor affect especially after the earthquake on May 12,2008 and disturbance of grazing, the Dry Valley in Upper Reach of Minjiang River has a serious ecological degradation. The water is an important limiting factor to local ecological construction, so we study the effect of different patterns surface mulching on growth of five species trees in Mountain Forests-Dry Valley Ecotones in the Upper Reach of Minjiang River. The results indicate:(1) The soil water preserving technique can both improve the soil moisture in dry season and rainy season effectively in Mountain Forests-Dry Valley Ecotones. The content of soil moisture in the dry season:grass cover>mulching film>turf cover>water barrier>control. The content of soil moisture in the rainy season: grass cover≥mulching film>turf cover>water barrier>control. The content of soil moisture in different kinds of trees in dry season:Poplars> elm>locust>Chinese pine>Minjiang cypress. This indicates that the water consumption of broad-leaved trees is lower than that of coniferous trees in dry season. The content of soil moisture in different kinds of trees in dry season: elm>Minjiang cypress>locust>Poplars>Chinese pine. This indicates that the difference of water consumption between broad-leaved trees and coniferous trees is significant.(2) The daily evaporation of different patterns surface mulching(grass cover, mulching film, turf cover, control)is a unimodal curve. It's peak is at 12:00-14:00 which is similar to the temperature behavior in a day. The daily evaporation of different patterns: control>grass cover> grass cover>mulching film. The daily evaporation of control is 2.4 times than that of mulching film. This indicates that mulching film can reduce soil moisture evaporation.(3) The soil water preserving technique can improve the plant living percent. The plant living percent: mulching film(81.22%)>grass cover(81.24%)>turf cover(80.12%)>water barrier(68.90%)>control(58.44%). The plant living percent of different kinds trees:Minjiang cypress (85.98%)>elm(83.88%)>locust(81.70%)>Chinese pine(81.65%)>Poplars(56.15%). The plant height annual increase:grass cover>mulching film＞turf cover>water barrier> control. The plant stem base annual increase:grass cover>mulching film>turf cover>water barrier>control. The plant stem base annual increase of different kinds trees:elm>Poplars> Minjiang cypress>Chinese pine>locust.(4) The indexes of physiological responds to drought stress of different trees are different. The content of Chlorophyll in different kinds trees: grass cover> mulching film>turf cover> water barrier>control. The content of hydroxyprolinemia, superoxide dismutase(SOD), malonaldehyde and soluble sugar in different kinds trees: control>water barrier>turf cover> mulching film>grass cover.(5) The soil water preserving technique can improve plant biomass. The plant biomass of Chinese pine and Minjiang cypress of different patterns surface mulching:mulching film>grass cover>turf cover>water barrier>control. The plant biomass of elm, Poplars and locust of different patterns surface mulching:grass cover>mulching film>turf cover>water barrier> control.(6) Mountain forests-Ecotones have a better natural condition so that the feasibility of vegetation restoration in this area is well. Having closed forest measure and reducing the disturbance of grazing, can speed the vegetation recovery and ecological construction in this area.