Study On Forestation Technology And Its Effects In Coastal Saline-alkaline Land

It is very difficult and demanding work for ecological restoration and afforestation in the coastal areas. This article was trying to find out the effective technical measures in Hebei Coastal Saline soil on the basis of the long-term research and practice on coastal saline soil in the afforestation. The paper sets the eco.& tech. development zone of Cangzhou Hebei as the experiment plots.First of all, this paper surveyed comprehensively of site conditions of the economic development zone, while analyzed relationship between the soil types and the natural plant community site types combined with the and vegetation survey. The results showed that soil salinity and vegetation types closely related and vegetation had a significant direct role on soil types in this development zone. So it was proposed basic ideas of vegetation construction for in different site conditions.Secondly, in the view of many years tracking and monitoring, water and salt movement in year was divided into four stages by the ratio of evaporation and precipitation:I spring Strong evaporation and salt accumulation stage,â…¡summer rainfall-leaching period, III autumn salt accumulation stage andâ…£winter evaporation relatively stable stage. Meanwhile, under the simulated soil column experiment the results find out the soil salinity variation of the one-dimensional water infiltration.Thirdly, in order to enrich the species of afforestation and vegetation in Coastal Saline land, Populus euphratica and other10 speices and 8 Tamarix speices of salt-tolerant plants was introduced in experiment. The adaptation of these plant speices were studied.Four forestration technologies were applied in experiment; they were geocomposite drainage systems, rainwater harvesting technology, salt-isolated layer and surface coverage technology. The experiment results indicatied that:geocomposite drainage systems was effectively improved the drainage capacity of forest land; rainwater harvesting technology was efficiently improved in the use of rainfall; salt-isolated layer was significantly reduced soil salt content; surface coverage treaments were decreased Salinity obviously and promoted the growth of Populus euphratica. Finally, the optimal combination of several techniques and in accordance with the characteristics of saline, it was summarized the two sets of afforestation technology optimization patterns:I Evaporation-reduction and drainage-promotion pattern, II rainwater-harvesting and reduce soil salinization and evaporation pattern. Experimental observation and the study results of two patterns found that:(1) slowed the accumulation of soil salinity and effectively reduced the salt content of soil; (2) effectively improved the tree's instantaneous water and energy use efficiency and strengthened photosynthetic physiological response capacity; (3) effectively improved the survival and growth of trees; (4) the redistribution of ions of soil was very significant, major ion concentrations were reduced by the trends; (5) soil nutrient conditions have been some improvement, but the nitrogen and phosphorus deficiency is more serious.