This is a second question about the same world described in this question about human reaction to an alien world.
So here's the idea: human beings travel to and land on an Earth-like world with the intention of colonizing it.
This world is remarkably Earth-like: gravity close to 1G, oxygen-nitrogen atmosphere with very close to the same proportions as Earth, similar climate, and similar life forms. So, in principle, a human could walk around unprotected on this world.
However...
The life on this planet, while at a similar level of development to that of Earth, is not based on the same DNA/RNA bases or the same amino acids in proteins. In short, the lifeforms on this planet resemble Earth life, but the chemistry is different.
Would our familiar Earth plants grow in such an environment?
It seems unlikely to me that alien bacteria, viruses, etc. would attack our plants - after all, the genetic material and proteins are different.
But what about the soil? My first thought is that humus on this planet would be made up of organic material from decomposing alien life (decomposed by alien bacteria), and therefore wouldn't provide a medium in which Earth plants could get the nutrients they need. But is that correct? I guess to some extent it depends on how much the humus is decomposed (ie. just down to proteins & amino acids, or broken down even further).