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Some people seem to have the idea that "chemical" fertilizers kill soil bacteria--nothing could be farther from the truth--bacteria need N, P and K as well as trace mineral just like plants though in different ratios.

During the cleanup of the Valdeze oil spill, scientist harnessed the power of bacteria to eat crude oil simply by spraying fertilizer on the oily rocks. Bacteria normally do not eat oil because it has no nutrients (N,P &K)--bacteria get their energy from doing the exact opposite of plants--converting organic carbon back to carbon dioxide, but they have to have Nutrients to grow and divide--by adding fertilizer to the oily rocks bacteria had everything they needed--organic carbon for energy and Nutrients for growth--a few weeks later the rocks were white where the fertilizer was sprayed--black and oily where it was not sprayed.

Soil works the same way--bacteria in soil will consume left over organic matter for energy, but in many cases cannot do that because there is no nutrient for growth. The downside of adding fertilizer is that it does help bacteria grow and consume the organic matter--then they die because there is no more food for energy--that is what leads to soil compaction.

You can see this wherever you have a soil profile like a new cut bank on the side of the road--ever notice the layers in a bank where soil has been deposited by erosion--there should be tons of organic matter--leaves and tree roots burried over time--, but unless the bank was a wetland where oxygen was excluded, bacteria over time will consume all of the organic matter as small amounts of nutrients are carried down by water--nutrients needed to consume low nutrient organic matter and convert it back to CO2.

Adding organic matter to the soil help improve the condition of the soil, the aeration, drainage ect, unfortunately adding fertilizer will help bacteria remove that organic matter, but it will still help plant growth.