Research And Application Of Biological Improver To Saline-alkali Soil

Aspergillum Niger and other acid bacteria can produce many acidic substances in the process of metabolism,including glycolic acid,oxalic acid,malice acid,citric acid and other organic acids.The analysis of these bacteria and their metabolites shows that these strains can also be used as saline-alkali soil biomodifiers.A series of systematically analyses were made for the selected acid producing strains and the effects of acid production on improved saline-alkali soil in this paper.The main results are as follows:A strain of acid was screened in acidic soil in a region with gradient dilution method and it was known as Aspergillums Niger A80.The metabolites of this aspergillums Niger were analyzed by HPLC after fermentation culture and the main components are citric acid.Through the optimized medium we can see the best carbon source was sucrose;the optimal nitrogen source is ammonium sulfate;the optimum additive is methanol.Through the response surface experiment for the fermentation of acid in the laboratory the optimum conditions is pH 7;3.5mg/L dissolved oxygen;25.5 ?;78 h.The improvement effect of biological modifier on soil showed Aspergillum Niger has the effect of reducing the pH of different types of saline alkaline soils.The modified effect of the same volume of fermented liquid in the saline-alkali soil is chloride salt soil greater than sulfate soil greater than heavy carbonate soil.It showed that aspergillums Niger was more tolerant to neutral salt than alkaline salt.At the same time,aspergillums Niger has the effect of reducing soil salt content.The salt content of sulfite was reduced by 17.8%.Chloride salt was reduced by 19.5%.The salt reduction of heavy carbonate soil was 15.2%.The effect of aspergillums Niger on the formation of pellet structure was observed?The agglomeration of the bioflocculant of aspergillums Niger and aspergillums Niger was analyzed.It is proved that the spherical structure of aspergillums Niger and its metabolites are the agglutinating effect of the granules of saline soil?At the same time,it can also remove excess Naa from soil and the removal rate is above 15%.The application of biobacteria for lettuce in simulated saline soil environment is shown that different concentration of salt solution processing of lettuce seedlings after watering the same volume of aspergillums Niger fermentation liquor has a significant difference in plants survival rate and growth.Treatment group survival rate more than 33%;water content more than 40%;relative growth rate up to 60%.The content of malondialdehyde could be reduced by more than 20%in raw vegetable leaves.Soilmicrobial activity increased by about 3 times compared with the control group.