Evaluation of microbial and enzymatic communities in soil and rizosphere from soybean plants.

Understanding the biological and biochemical soil properties, as well as its enzymatic activity is important in designing an efficient alternative to demonstrate desired modifications in the soil. Such modifications are related to crop systems, cultivation practices or other human activities. The objective of this study was to evaluate the diversity of some microorganisms ( Bacillus , Pseudomonas , Trichoderma and Fusarium ) and enzymatic activity in soil from soybean crops with different yields. Soil sampling was determined according to the productivity yields of the property, which were divided into high, medium, and low yield. Microorganisms were evaluated by counting populations of fungi and bacteria through serial dilutions of total bacteria, Bacillus, Pseudomonas, Trichoderma and Fusarium. The \u3b2-glucosidase, acid phosphatase and arylsulphatase activities were determined by spectrophotometry after one hour of incubation at 37 \ub0C, with the specific substrate p-nitrophenol-\u3b2-D-glucopyranoside, p-nitrophenol-phosphate and p-nitrophenyl sulphate, respectively, for each studied enzyme. Urease was determined by the ammonium release method, after incubating the soil with urea for two hours, at 37 \ub0C. Soil samples from the high-yield plot had higher concentrations of Bacillus and total bacteria. The low-yield soil showed a higher level of colonies of the genus Fusarium. The studied enzyme activities (\u3b2-glycosidase, arylsulphatase and urea) were found at lower values in soil samples from the high-yield field and differed statistically from the low-yield field. However, in the rhizosphere samples, these enzymes had a higher activity in the high-yield field. In view of these results, it is possible that the yield of soybean plants influences the number of microorganisms and the enzymatic activity of the soil microbiota.Comprendre les propri\ue9t\ue9s biologiques et biochimiques du sol, de m\ueame que son activit\ue9 enzymatique est important dans la mise \u153uvre d\u2019une alternative efficiente pour d\ue9montrer les modifications d\ue9sir\ue9es dans le sol. De telles modifications sont reli\ue9es aux syst\ue8mes de culture, pratiques culturales ou les autres activit\ue9s humaines. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la diversit\ue9 de quelques microorganismes ( Bacillus , Pseudomonas , Trichoderma and Fusarium ) et activit\ue9 enzymatique dans le sol des cultures du soja avec diff\ue9rents rendements. L\u2019\ue9chantillonnage des sols \ue9tait d\ue9termin\ue9 selon la productivit\ue9 de la propri\ue9t\ue9, qui \ue9tait divis\ue9e en \ue9lev\ue9e, moyenne et faible rendement. Les microorganismes \ue9taient \ue9valu\ue9s par comptage des populations des champignons et bact\ue9ries \ue0 travers des s\ue9ries de dilutions des bact\ue9ries totales, Bacillus, Pseudomonas, Trichoderma and Fusarium. Les activit\ue9s du b-glucosidase, acide phosphatase et arylsulphatase \ue9taient d\ue9termin\ue9es par la spectrophotom\ue9trie apr\ue8s une heure d\u2019incubation \ue0 37\ub0C, avec le substrat sp\ue9cifique de p-nitrophenol-\u3b2-D-glucopyranoside, p-nitrophenol-phosphate et p-nitrophenyl sulphate, respectivement, pour chaque enzyme \ue9tudi\ue9e. Ur\ue9ase \ue9tait d\ue9termin\ue9e par la m\ue9thode de la lib\ue9ration d\u2019ammonium, apr\ue8s incubation du sol avec l\u2019ur\ue9e pendant deux heures, \ue0 37\ub0C. Les \ue9chantillons des terres \ue0 haut rendement ont les concentrations \ue9lev\ue9es en Bacillus et bact\ue9rie totale. Les terres \ue0 faible rendement ont montr\ue9 un niveau \ue9lev\ue9 de colonies du genre Fusarium. Les activit\ue9s des enzymes \ue9tudi\ue9es (b-glycosidase, arylsulphatase et ur\ue9e) \ue9taient trouv\ue9es \ue0 de faibles valeurs dans les \ue9chantillons de terres \ue0 haut rendement et diff\ue8rent statistiquement des terres \ue0 faible rendement. N\ue9anmoins, dans les \ue9chantillons de la rhizosph\ue8re, ces enzymes ont une activit\ue9 \ue9lev\ue9e sur les terres \ue0 rendement \ue9lev\ue9. D\u2019apr\ue8s ces r\ue9sultats, il est possible que le rendement des plants du soja influence le nombre de microorganismes et l\u2019activit\ue9 des enzymes des sols microbiote