Originally Posted by phasthound
I'll have to let my clients know that the results they are seeing from using soil building methods and products are just figments of their imaginations.
I'm sur that your results are only from microbial and organic products
All microbial and "organic" products I've seen (SumaGrow and Holganix included) have plenty of N and Fe in them. No scientific study has found those products to give any effect different than similar amounts of straight urea and Fe. I've done research with almost all of these products and have found no difference between them and simple urea or Fe for color, growth, density, and disease incidence. I've also found chlorophyll a, chlorophyll b, and total non-structural carbohydrates to be higher with simple urea than with any of the microbials or "organics." Additionally, soil microbial counts and populations were the same for all treatments. The microbials and "organics" did no better on the surface than conventional management and they did not positively impact plant performance.
The guys who fall hook-line-and-sinker for these products often fail to account for the variation in their "tests." They combine their snake oils with conventional ferts, hiding the lack of results from the snake oil. Or, maybe they think they should combine proper cultural practices with the snake oils and rave about how much better they are than the previous program, when they didn't have the proper cultural practices in the original program to begin with. You can't just look at a lawn after making more than one change and say that it works. You're just fooling yourself.
The bottom line is that the science doesn't support these products. That being said, you can apply to lawns whatever you want, but there is no evidence to support your claims. You can show me pictures of all the corn and soybean roots that you can find, but the actual studies don't show increased crop performance and they don't show how this can improve turfgrass performance.
I understand that you really believe in this product and will endorse it whether it works or not. I just wanted to offer everyone a perspective rooted in science, so that everyone has information with which to make up his own mind.