| Rhizobox simulation test and field trials conducted in dingxi during 2008 were used to study the influence of rhizobium inoculation on pea rhizosphere microorganisms, soil enzymes, the dynamic changes and horizontal distribution characteristic of soil nutrients, nodulation, growth and yield. The main conclusions are as follows:1.The number of bacteria is the highest(90.83%～99.63%),then followed by actinomycetes(0.29%～5.8%)and fungi (0.08%～3.37%)among the pea rhizosphere microorganisms.2.Rhizobium inoculation increased the number of rhizosphere microorganisms. The average figures of microorganisms in pea root-soil interface in its three growth stages(flowering stage, pod filling stage and maturing stage)are ACCC16103(Pea nodule bateria from Agricultural Microbial Culture Collection Center of the Chinese Academy of Agricultural Sciences(abbreviation ACCC), abbreviation B2.The same blow)(6.5×10~7cfu/g dry soil)﹥ACCC16101(B1)(3.26×10~7cfu/g dry soil)﹥CK(3.03×10~7cfu/g dry soil).Compared with CK, the average figures increased by 114.5% on inoculation B2 and 7.59% on inoculation B1;the average figures of microorganisms in the 0 ~ 2mm rhizosphere department are B2(1.85×10~7cfu/g dry soil)﹥ACCC16101(B1) (1.31×10~7cfu/g dry soil)﹥CK(0.58×10~7cfu/g dry soil), compared with CK, the average figures increased by 218.97% on inoculation B2 and 125.86% on inoculation B1.3.From flowering period to mature stage, the horizontal change trends of the microorganisms number showed the performance of root-soil interface aggregation obviously; inoculation made no effect on the dynamic changes trends of pea root-soil interface microorganisms and the rhizosphere horizontal change trends. From flowering period to podding stage, the number of rhizosphere bacteria increased, and it reached the peak up to podding period then desending; the number of fungi showed a growing trend in general, which reached its peak at maturity; actinomycetes present downtrend gradually.4.Inoculation promoted nitrogen transmutation in root-soil interface during flowering stage, increased soil nitrogen contents in maturing stage, improved nitrogen production of the coming crops; inoculation made no significant effect on the dynamic change of root-soil interface urease activity, while the differences of the dynamic change of root-soil interface catalase activity among different bacterium agent were significant.Compared with CK, the activity of root-soil interface urease increased by 3.4% on inoculation B1 and 5.63% on inoculation B2 in flowering stage, while decreased by 3.56% and 8.58% at maturity. From flowering stage to podding period, the dynamic change of root-soil interface soil urease activity shows "V"-shaped trend, soil enzyme activity increased gradually before podding period, which reached the highest up to podding period and reduced gradually at maturity. For CK and inoculation B1, the activity of root-soil interface soil catalase showed the same "V"-shaped trend as root-soil interface soil urease; for inoculation B2, from flowering period to maturity, the activity of soil catalase increased gradually, which reached the peak up to mature period.5.Rhizobium inoculation increased the contents of root-soil interface available phosphorus significantly in the pea flowering stage, promoted the absorption of nitrogen in peas; inoculation made no significant effect on the trends of pea rhizosphere nutrient and the horizontal distribution of soil enzymes. Compared with CK, the contents of pea root-soil interface available phosphorus, ammonium nitrogen and total nitrogen increased by 18.27%, 13.64%, -24.56% on inoculation B1, while increased by 42.89%,50%,-19.5% on inoculation B2; it increased greaterly that the available nutrient content of pea root-soil interface on inoculation B2 than inoculation B1.The rhizosphere urease horizontal change showed the tendency of "down - up - down– up"in flowering and podding stage,and it showed "U"-shaped trend at maturity. Horizontal change characteristic of rhizosphere catalase were as follows: with the horizontal distance from the root system increasing, horizontal distribution characteristic of rhizosphere catalase showed "W"-shaped trend in flowering stage; rhizosphere catalase activity decreased slightly in podding period, it reached the lowest point in > 10mm soil; rhizosphere catalase activity decreased gradually from root-soil interface to 4~6mm,increased gradually from 4~6mm to 8~10mm, decreased slightly in > 10mm soil at maturity. |
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