The Research Of Key Parameters In The Engineering Application Of Soil Seed Bank

As the important material basis of plant community's vegetation restoration and natural regeneration,soil seed bank has been proven to be an effective method to restore the vegetation.In Japan,Australia and other regions,there are numerous successful cases using soil seed bank for vegetation restoration and greening.However,The current domestic research on soil seed bank is mainly focused on the theoretical aspects,and studies of vegetation restoration are less.Successful cases of Japanese soil seed bank's vegetation restoration as well as a large number of experimental foundation for reference,the influence of engineering applications factors including planting substrates'proportion,nitrogen fertilizer,phosphorus fertilizer and moisture gradient on the soil seed bank's germination characteristics and germination plants'above ground biomass are studied;Then,the optimum germination range of each factor were found by single factor germination experiments,orthogonal experimental and response surface optimization design were explored the interactional effects of nitrogen,phosphorus and moisture gradient on soil seed bank.In addition,analytic hierarchy process and gray correlation analysis method to obtain optimum plan for the vegetation restoration in Tianjin coastal saline soil.The results are shown as follows:An optimum plan for the vegetation restoration in Tianjin coastal saline soil has been obtained by analytic hierarchy process and gray correlation analysis.In single factor germination experiments,the moderate ratio of planting substrates proportion,nitrogen fertilizer,phosphate fertilizer and moisture gradient could effectively promoted the germination and seedling growth on soil seed bank.When the volume ratio of peat and perlite was 1:1,mixed with topsoil in 35%,the germination density of soil seed bank,Shannon-Wiener diversity index and germination plants'aboveground biomass index all reached maximum;when additions of nitrogen was10g/m² and 20g/m²,the soil seed bank's germination density and germination plants'aboveground biomass reached the maximum respectively;when additions of phosphorus was 10g/m²,the soil seed bank's germination density and germination plants'aboveground biomass reached the maximum;when the moisture gradient was20mm?1000m L?,the soil seed bank's germination density and Shannon-Wiener diversity index both reached maximum,and moisture gradient addition significantantly effects germination plants'aboveground biomass of soil seed bank.Considering various factors impacting on germination characteristic and seedling growth of soil seed bank,optimum addition levels of nitrogen fertilizer and phosphate fertilizer was 5-20g/m² and 5-15g/m² respectively,optimum addition level of moisture gradient was 10-30mm?500-1500mL?.Orthogonal experiments and response surface optimization experiments were designed based on the best range of single germination experiments.The experimental results show that optimal solution of orthogonal experiment was plot5?A2B2C3?,with the nitrogen of 10g/m²,phosphate of 10g/m²,moisture gradient of 30mm?1500m L?;an optimal solution of response surface optimization was nitrogen of 13.54g/m²,phosphate of 9.47g/m²,moisture gradient of 30mm?1500mL?.Using the method of analytic hierarchy process and gray correlation analysis to evaluate two experimental methods,the best scheme of early vegetation restoration effect in the orthogonal experiment were nitrogen of 10g/m²,phosphate of 10g/m²,moisture gradient of 30mm?1500m L?.While the best scheme of early vegetation restoration effect in the response surface optimization experiment were the nitrogen of 12.5g/m²,phosphate of 10g/m²,moisture gradient of 20mm?1000mL?,the results of the two methods were also basically the same,however the moisture gradient addition level of the optimal response surface optimization experiment was relatively lower?compared to 1500m L,the reduced rainfall was about 10mm?.It saved water resources in the actual vegetation restoration,and it greatly reduced the economic cost of vegetation restoration project and furthermore has more practical significance.Therefore,the most suitable scheme of soil seed bank's vegetation restoration in Tianjin coastal area were nitrogen of 12.5g/m²,phosphate of 10g/m²,moisture gradient of 20mm?1000mL?.Effects of nitrogen,phosphorus and moisture gradient's addition on soil physical and chemical properties were studied.It found that the germination density of soil seed bank was significantly positive correlated with ammonium nitrogen?NH₄⁺-N?,Shannon-Wiener diversity index and Simpson dominance index both were significant negatively correlated with total salt?sc?and total phosphorus?TP?,Pielou evenness index was significantly negatively correlated with the total phosphorus?TP?,number of species was significant negatively correlated with the total salt?sc?;The CCA ordination analysis of soil seed bank's germination plant species and soil environmental factors showed that ammonium nitrogen?NH₄⁺-N?and pH had the greatest impact on the distribution of plant species,followed by organic carbon?org-C?,total nitrogen?TN?,total salt?sc?,nitrate nitrogen?NO₃^--N?.Moreover,the distribution of plant species on soil physical and chemical properties had obvious preference.