Hello. haven't tried watching articles about suppressive soils? So from a little experience I can say that Arthrobacter does not like acidic soils. And Beijerinckia and Klebsiella, on the contrary, prefer an acidic environment. In my opinion, it all depends on the specific type

doi: 10.1046/j.1365-294x.2003.01754.x.. 2003 Apr;12(4):917-29.Mol Ecol

Distribution and diversity of rhizobia nodulating agroforestry legumes in soils from three continents in the tropics

Abdullah Bala 1, Phillip Murphy, Ken E Giller

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• PMID: 12753212
• DOI: 10.1046/j.1365-294x.2003.01754.x

Abstract

The natural rhizobial populations of Calliandra calothyrsus, Gliricidia sepium, Leucaena leucocephala and Sesbania sesban were assessed in soils from nine sites across tropical areas of three continents. The rhizobial population size varied from undetectable numbers to 1.8 x 104 cells/g of soil depending on the trap host and the soil. Calliandra calothyrsus was the most promiscuous legume, nodulating in eight soils, while S. sesban nodulated in only one of the soils. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analyses of the 16S rRNA gene and the internally transcribed spacer (ITS) region between the 16S and 23S rRNA genes were used to assess the diversity and relative abundance of rhizobia trapped from seven of the soils by C. calothyrsus, G. sepium and L. leucocephala. Representatives of the 16S rRNA RFLP groups were also subjected to sequence analysis of the first 950 base pairs of the 16S rRNA gene. Eighty ITS groups were obtained, with none of the ITS types being sampled in more than one soil. RFLP analysis of the 16S rRNA yielded 23 'species' groups distributed among the Rhizobium, Mesorhizobium, Sinorhizobium and Agrobacterium branches of the rhizobial phylogenetic tree. The phylogeny of the isolates was independent of the site

The population of rhizobia in the soil is dependent on the growth of legume crops which foster their increase.

Rhizobia are usually most active in low nitrogen soils as high nitrogen soils cause the plants to stop to secrete chemical elicitors with draw in the bacteria into the jost roots.

Many Rhizobia are quite specific in their host range these are hardier to maintain in the soil.

Most Rhizbobia require a mean neutral pH and thrive in environment of adequate trace minerals needed for the bacterial symbiant.

Soil is classified into four types:

Sandy soil.

Silt Soil.

Clay Soil.

Loamy Soil

All soil contains bacteria. An acre of soil can hold nearly 5- 10 tons of living organisms and another interesting fact is that one measly gram of soil will hold about 5000- 7000 bacteria species. A teaspoon of productive soil generally contains between 100 million and 1 billion bacteria . The pH range 5.5–6.5 is optimal for plant growth as the availability of nutrients is optimal. This is also so for most soil microbes, in part because in this range plants grow well and produce more root exudates as a carbon source available for survival and multiplication of microbes.The Rhizobium or Bradyrhizobium bacteria colonize the host plant's root system and cause the roots to form nodules to house the bacteria. The bacteria then begin to fix the nitrogen required by the plant. There are basically four functional soil bacteria groups including decomposers, mutalists, pathogens and lithotrophs.It has been shown that the efficiency of the symbiotic process depends on many factors including the host plant, bacteria, the process of symbiosis, and the environment. Among the most important constraints affecting plant growth and the process of fixation are the soils, which are not highly fertile, resulting in the limited availability of macro- and micronutrients

The main source of microbial nitrogen fixation is the bacteria of the genus Rhizobia. These bacteria form a symbiotic relationship with only legume plants, like soybeans, green beans, clover, and alfalfa. They are found in soil and aquatic.

Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria such as Azotobacter and archaea. Some nitrogen-fixing bacteria have symbiotic relationships with plant groups, especially legumes.