Abstract: This study examined the effects of applying different soil amendments on the growth and arbuscular mycorrhizal symbiosis of saline-alkali soil alfalfa in the Hailiutu science park-area of Inner Mongolia Agricultural University.Soil amendments effectively promoted the growth of alfalfa and the arbuscular mycorrhizal symbiosis,but the effects of different amendments on alfalfa growth and mycorrhizal indices were different.Among them,the greatest plant height,plant yield,and leaf SPAD were observed in the organic fertilizer+amendment T treatment,and were 27.1%,126.2% and 4.0% higher than the control,respectively.The amendment E produced the largest leaf weight,the largest leaf/stem ratio,and the largest mycorrhizal infection rate,and were 64.5%,42.1%,and 59.9% higher than that of the control,respectively.The stem weight of alfalfa was greatest in the compound fertilizer+organic fertilizer+amendment E treatment,and was 19.2% higher than that of the control.The C content of alfalfa in the compound fertilizer+organic fertilizer+amendment T+amendment E treatment was the highest,being 87.4% greater than the control.The content of N in alfalfa in the amendment T treatment was the largest,while the C/N ratio was the smallest,being 291.4% higher and 67.3% lower than the control,respectively.The P content of alfalfa in the amendment T+amendment E was the largest,and was 246.5% higher than the control;the rhizosphere mycorrhizal spore density in the compound fertilizer+organic fertilizer+amendment T treatment was the highest,being 7.8 times that of the control.According to the effect of different amendments on the various indices and the use value of each index,a comprehensive score was calculated for the different treatments:amendment E(10.35)>amendment T(8.61)>organic fertilizer+amendment T(8.12)>compound fertilizer+organic fertilizer+amendment T(7.76)>compound fertilizer+amendment T+amendment E(7.51)>organic fertilizer+amendment T+amendment E(7.49)>compound fertilizer+amendment E(7.43)>organic fertilizer+amendment E(7.34)>compound fertilizer+Organic fertilizer+amendment E(6.99)>compound fertilizer+amendment T(6.50)>compound fertilizer+organic fertilizer+amendment T+amendment E(5.98)>amendment T+amendment E(5.42)>control(1.5).From the effects of the different amendments on the growth of the mycorrhizal mantle,for alfalfa planted on alkaline earth soil with similar characteristics to that of the experiment,the best results will be obtained from using amendment E,amendment T and organic fertilizer+amendment.

Key words: Amendment;Saline-alkali soil;Alfalfa growth;Mycorrhizal symbiosis