Yes, the main reasons of soil microbial biodiversity are: organic matter level, land use change and habitat disruption, over exploitation of soil resources, change of climate and hydro-logical regimes, change of geo-chemical properties etc. At the species level, the main changes are occur from change in environmental conditions, change in geochemical properties, competition with invasive species and effect of ecotoxins. Soil microbial biodiversity may be affected also at the gene level due to pressure derived from genetic pollution. Therefore, with increase and decrease in altitude you may always find the effect on soil microbial biodiversity. You may also notice microbial biodiversity with agricultural intensification and over-exploitation, soil erosin, soil sealing, soil pollution, soil compaction, habitat fragmentation, and due to fire.

Previous discussion on similar topic may also be viewed

https://www.researchgate.net/post/bacteria_from_high_altitude

Yes clearly, I am living in an altitude of 4000 feet above sea level. The cold starts from Oct of the first year-March second year. In those periods, I don't find insects creeping on the grounds. Everywhere is silent, no insects so no birds. If no insects, then might at that period no more microbes, because these insects usually transmit microbes to other areas or plants. So diversity in that period and in that altitude is minimum. Less activities and less microorganisms. In the other tropical and subtropical areas which are just 1000 feet or somewhat 600 feet above sea level, there are always, I found insects beeping and crawling, it seems more microorganisms activities. Finally it can be concluded, with the altitude off course altitude has effect on diversity of organisms. 

Yes, definitely, the main reason that altitude affect microbial diversity is that altitude affects or determine the temperature of a particular area. All other factors kept constant, maximum microbial diversity and activities occur in areas with temperature ranging between 30-35 degree centigrade and such temperature occurs in areas with altitude ranging between 1000 - 1500 meters above sea level (just estimate). However, as altitude increase beyond >1500, the area become cooler and cooler thus micriobial activity and diversity also decrease. Similarly as the altitude further decrease below 1000 mabsl, the area becomes hotter and hotter decreasing micriobial activity and diversity. So there is definitely a relation between micriobial biodiversity and activity with altitude but the effect of altitude is more of indirect through its effect on temperature.

 @ J. C. Tarafdar . Dear Sir thank you so much for valuable information.

@ Nilay Borah . Thank you sir for the articles.

@ Aqleem Abbas . Thank you sir you gave me a new idea which I did not  pray in consideration

@ Wassie Haile . Thank you sir for the exact answers

Please refer to the attached paper

Dear Rebati Nadia

Please, check my attachment, thanks a lot, best regards, Eduardo

temperature and pressure will be gradually depleted in line with increase of altitude.  it will directly impact to the metabolism of microbes.  microbes are sensitive to environment changing.  indirectly, low temperature will inhibit decomposition of organic compound then will deplete population of heteretrophic microbes as well.