Effect Of Lolium Multifolrum Application On Community Of Tobacco Soil Microorganism

This experiment was studied the effects of ryegrass grown on the quantities of tobacco soil bacteria,fungi,actinomycetes and antagonistic actinomycetes.Soil bacteria,fungi and antagonistic actinomycetes was identified by cell morphology,cultural characteristics and physiological and biochemical indicators. The studies reflected the changes of soil microorganism community,which carried out in scientific and technological demonstration park of tobacco in Youyang from March 2008 to November 2009.The mainly results were as follows:1.Effect of ryegrass grown on the quantities of microorganismThe quantity change of the soil microorganisms around the roots of tobaccos was accordant among each fields in 2008.The growth of the same kind of different microorganism had the equal amount, which reached the peak number, and at the same time, soil bacteria, fungi and actinomyces were respectively 6.87×106cfu/g dry soil,4.91×104cfu/g dry soil,9.41×105 cfu/g dry soil.The microorganism quantity of lolium perenne planting in green fields and control fields reached the peak number on August 23 (maturation period) in 2009, and the mean value of microorganism quantity in green fields was 12.20×106/g dry soil, which was significantly more than 6.61×106/g dry land in control fields of the same year, and was more than the microorganism quantity in the same field of previous year. That indicated lolium perenne planting was propitious to the increasement of microorganism quantity.The number of soil actinomyces had been increased after tobacco transplanting in the green fields with lolium perenne planting, and it reached the peak value after tobacco harvest (about October 15).The mean value was 8.96×105/g dry land, and was a bit more than the peak value of soil actinomyces which was 8.49×105/g dry land.2. Effect of ryegrass grown on the quantities of antagonistic actinomycetesThe quality of soil actinomyces with antagonism activity to the P. parasitica var. in the green fields was 29, which accounted for 40.3% in the total of isolated strains, and was more than 20.0% in the control fields. The ratio of strains with antagonism activity in the green fields was much higher than that in the control fields. The number of strains with antagonism activity in the green fields was 14, which accounted for 48.3%strains with antagonistic activity, and was more than 33.3% in the control fields. The best effect in the green fields was BXL17,whose bandwidth reached 25.7mm. The best effect in the control fields was 27.8mm, which was more than the bandwidth in the green fields.The quality of soil actinomyces with antagonism activity to the R. solanacearum in the green fields wasl4, which accounted for 19.4% in the total of isolated strains, and was more than 13.3% in the control fields. The ratio of strains with antagonism activity in the green fields was much higher than that in the control fields.The number of strains with antagonism activity in the green fields was 10, which accounted for 71.4% strains with antagonistic activity, and was more than 25% in the control fields. The best effect in the green fields was Q-BXL4,whose diameter of inhibition zone was 44.0mm. The best effect in the control fields was 26.0mm, which was less than the diameter of inhibition zone in the green fields.In a word, ryegrass grown increased the antagonistic actinomycetes quantity to P. parasitica var., R. solanacearum.3.Effect of ryegrass grown on the genera of antagonistic actinomycetesThe genera of actinomycetes with antagonistic activity in green manure fields were more than these of control fields.The 12 stains of antagonistic actinomycetes in green manure fields mainly releted to 5 genera, which had 6 class groups among streptomyces.These 6 actinomyces strains with antagonism activity in the control fields mainly refered to 3 genera, which had 3class groups among streptomyces.4. Effect of ryegrass grown on soil microorganism diversityGreen manure fields of tobacco rhizobacteria to Gram-negative bacteria mainly belonged to 13 genera, only 6 genera in control field. Of these, Pseudomonas and Bacillus were the dominant genera in green manure fields and control fields; The bacteria on plant pathogenic role, such as Erwinia, Xanthomonas and other bacteria, were mostly distributed in the control field;The antagonism of plant pathogens with the beneficial bacteria,such as Bacillus,Alcaligenes and other bacteria,were distributed in the green manure field. The soil bacterial population diversity index and richness index in green manure fields was higher than in control fields, while taxa evenness index and dominance index was lower than in control fields.