Nematodes, esp. the root knot variety, are a serious pest. The growers of exotic plants must be especially wary, since some nematodes that don't cause too much damage in the garden are a threat to greenhouse plants.
This area of Alberta was essentially nematode-free, but poor inspection of imported plants has changed that. With some garden crops, like tomatoes, nematode-resistant varieties are available. Alfalfa has been infected in the warmest part of the province, but resistant varieties and crop rotation help to control it.
Most extension services provide information, of the many here is one from Missouri: Nematode control

Bacillus thuringiensis (Bt) offers a mixed blessing. It infects most butterfly and moth species as well as the caterpillers of garden and crop pests. It action has been engineered into a number of crop seeds sold as 'insect resistant.' Some of the loss of butterflies and moths needed for propagation of some plants has been blamed on Bt and its engineered actions in plants.

Moreover, soil mixtures such as recommended by SRS may be effective in some climatic zones but not others. Use of molasses could be detrimental in cool climate areas. Careful testing is necessary since products of that type could encourage soil molds that rot roots. In our area, for example, bone meal causes mold problems unless it is confined to the bottom soil, otherwise roots may be destroyed.

Lava and green sand (from volcanic materials) of course are good sources of minerals needed for most plant growth. In Hawai'i, I have seen new homes built in areas of lava rock and almost no soil. To pepare a 'soil,' the rock is crushed, and a little bagged soil added. Good plant growth results in what still looks like crushed lava. In Florida, I have seen field crops in soil that is mostly broken up limestone (rich in phosphate in that area).