Research On The Improvement Of Microbial Inoculants On Saline-alkali Land

A large amount of saline alkali soil exists in China,and its improvement is very important in modern agriculture.Microbial treatment is the main way to improve saline alkali soil,but the improvement mechanism is not clear.In order to explore the microbial improvement mechanism for saline alkali soil and improve the improvement effect of commercial microbial agents,this article focused on improving saline soil in Tianjin Dagang,with effective microorganisms(EM)and salt-tolerant strain was isolated from saline-alkali land as modified material,setting single treatments and compound treatment combine with alfalfa,applied to explore these microbes on the effect and mechanism of alkali-saline land.Using alfalfa as a target for planting trees,the improvement of physical and chemical properties and available nutrients of saline-alkali soil under different treatments,the promotion of alfalfa plant growth and the changes of the structure diversity and richness of rhizosphere microorganism were observed through pot experiment.The contents of p H,electricity conductivity(EC),organic matter,available nutrients nitrogen,phosphorus and potassium before and after the experiment were observed in the pot experiment without alfalfa planting.In the pot experiment of planting alfalfa,the germination rate,root length,stem length,fresh weight,dry weight,malondialdehyde,proline and soluble protein content of alfalfa seeds were counted.The main experimental results were as follows:(1)Four saline/alkali-tolerant strains were isolated and screened.Through morphological observation and genetic sequence analysis of 18 Sr DNA and 16 Sr DNA,strains were identified as Fusarium oxysporum(F.oxysporum),named TJPU08;Streptomyces capoamus(S.capoamus),named TJPU09;Rhodotorila mucilaginosa(R.mucilaginosa),named TJPU10;Bacillus cereus(B.cereus),named TJPU11,respectively.It was found that all the strains had the ability to dissolve phosphorus in liquid culture medium,and TJPU11 had the strongest ability to dissolve phosphorus.(2)The effects of EM and strains TJPU08,TJPU09,TJPU10 and TJPU11 on the physicochemical properties and nutrient indexes of saline-alkali soil were studied in the pot experiment without alfalfa.The results showed that all of the five strains could reduce p H and EC,reduce saline-alkali stress,increase accumulation of organic matter and conversion of available nutrients nitrogen,phosphorus and potassium,and the selected indigenous microorganisms could improve the soil condition,making them a kind of microorganism with broad application prospects.(3)In the pot experiment of alfalfa planting,the effects of EM and strains TJPU08,TJPU09,TJPU10 and TJPU11 on the growth of alfalfa were also studied.The results showed that the germination rate of alfalfa increased significantly after five treatments.In addition,EM,TJPU09,TJPU10 and TJPU11 all reduced the accumulation of malondialdehyde in plants,increased the content of proline and soluble protein,and alleviated the saline-alkali stress of plants.In addition,the combined action of strains and plants greatly promoted the change of soil,making the improvement of soil condition more significant.The inoculation of EM agent and TJPU08,TJPU09,TJPU10,TJPU11 increased the abundance of bacteria in the soil,greatly promoted the growth of dominant bacteria,and the effect was significantly better than that of the blank group.At the same time,the growth of some fungal genera was inhibited by these four treatments.