Mixed Forest On Soil Improvement In Saline-alkali Soil Of Yellow River Delta

The Yellow River delta is an important energy base in China, with the increase of population and the development of the national economy, the development and utilization of natural resources is the inevitable choice. Land degradation in the Yellow River Delta is not only environmental problems, but also relates to the social and economic problems. Therefore, with the concept of sustainable development deeply rooted in people’s heart today, to carry out the different habitats in soil physical and chemical properties, enzyme activity and regional, typical vegetation restoration technology, aims to put forward to accelerate heavy salin-alkali land vegetation recovery and prevent land salt degradation of forestry sustainable utilization technology and mode, scientific soil improvement, be bred energetically and protection of forest resources not only for the degraded land effective remediation and ecological reconstruction plays an exemplary role and practical significance, but also for improving the local environment for human survival and sustainable development also has important social and economic significance.In this paper, a method of combining field surveys and experiments, conducted a survey of the Yellow River Delta plantation techniques and understory vegetation, soil properties of different ages, different soil layer, different mixed mode, to understand the afforestation technology, and different ages, different soil, different mixed mode mixed forest vegetation and soil characteristics, and experimental study to find out the vegetation and soil properties of different ages, different soil, different mixed mode mix eddetermine the relationship between vegetation growth and development status of afforestation and soil characteristics in order to determine the method of saline-alkali soil improvement of the Yellow River Delta.The main findings are as follows:1. Improved afforestation technology saline-alkali soil of the Yellow River DeltaThe Yellow River delta saline-alkali soil amelioration forestation techniques mainly include ditches removing alkali, built field, land reform alkali, paving isolation layer, water improvement measures, agricultural improvement measures, biological amelioration measures and chemical improvement measures, the study above saline-alkali soil improvement afforestation the development and application of the blind ditch change of alkali technology, and achieved good results.2. Understory vegetation species and diversity features of different age in Yellow River delta. Survey of the Yellow River Delta of different age mixed under story vegetation, ecosystems in the field there were24kinds of plant community species, belonging to13families and24genera, mainly Gramineae, followed by Chenopodiaceae and Asteraceae. Different ages mixed understory vegetation dominant species changes, born1years mixed understory vegetation dominant species are barnyardgrass (Echinochloa crusgali), born8years mixed understory vegetation of the dominant species are plantain (Plantago asiatica L), born22years mixed understory vegetation dominant species are Korean Cleistogenes grass (Cleistogenes squarrosa).WWith the mixed forest stand age increases, the types of vegetation, biological quantity, species diversity are increasing, dominant species are changing, in vegetation types from the sun into shade shade-tolerant vegetation types.3. Soil properties and soil enzyme activity variation of different age mixed forest in Yellow River Delta.Select1year old,8years old,22-year-old mixed forest. The experimental results show that, with the age growth, mixed forest and soil characteristics can significantly improve. Soil organic matter, total nitrogen and available nutrients content of an upward trend with the growth of age; soil PH and salt content decreased. A variety of nutrients in the soil on the vertical gradient changes are more obvious, and soil organic matter, total N and available nutrient content of topsoil are more than in subsoil, but soil pH and salinity in the topsoil content is lower than the bottom.Different age mixed soil enzyme activity is generally low, the surface soil enzyme activity is generally high, with the soil depth, soil enzyme activity decreased. With the growth of forest age, each layer of soil enzyme activity gradually increased, the protease activity is more stable, alkaline phosphatase, urease and peroxide increased in varying degrees, especially in the topsoil soil enzyme activity enhancements. The experimental results show that, with the age growth, mixed forest on soil nutrient content, enzyme content accumulation and reduction of PH, containing the soil salt has obvious improvement effects.4. Mixed benefit comparison of different mixed patterns of mixed forest in Yellow River delta ofSelect the locust ailanthus, locust elm, locust ash, locust sophora japonica in four different mixed way to make a survey of the soil properties and soil enzyme activity. The experiments show that the mixed layers and the full layer of soil physical and chemical properties and soil enzyme activity levels are higher than the pure forest, and mixed way mixed soil organic matter, total nitrogen, available nutrients compared to the locust pure forest of the increase is that in the locust ash is greater than in the locust Ailanthus greater,in the locust Ailanthus is greater than in the locust pagoda, in the locust pagoda is greater than in the locust elm; according to the changes in the soil PH, salt content, determine the inhibition of the locust ash mixed soil back to the salt works best; Activity of different mixed-mode mixed soil locust ash soil enzyme activities in the highest, consistent with the soil nutrient. Therefore, different mixed patterns of mixed forest of black locust Robinia pseudoacacia mixed benefit ash is better than that of Ailanthus altissima superior locust superior locust elm tree.