On a recent trip, I was once again presented with many questions regarding soil structures, soil testing, and fertility. Soil is one of my favorite things to speak about and I welcomed the opportunities to expand and hypothesize about the inner workings of soil ecosystems. Some of the questions that were raised about soil testing were essentially, “red herrings.” I was asked several questions about items on soil reports that are placed onto standard reports with no real reason, explanation, or purpose for being there. A quick review of Lawncology® 6 will remind you of my opinions on soils sampling and how soil tests are mainly used to sell fertilizer, not to create fertility.

The process that has been used for modern agriculture to “maintain soil health” has been abused for decades in the turf care industry. Lawncology® 14 covers this topic in more detail.  For purposes of this article, the point of focus is the following: The methods of soil testing / fertility measurement are not and should never be considered equal.  Agriculture soil testing methodology is actually designed to just measure what is there that needs to be “preserved” in order to produce a crop. The process is simple and based on the following formula:  nutrients needed to create a desired yield – nutrients that currently exist = nutrients that need to be applied.  This methodology is based on “conservation” of nutrients (and the related input costs) and has been used for decades in crop production. However, is it a good methodology to follow for soil fertility and plant health? Is this an efficient way to set a standard for meeting expectations?  Does this work for lawn care at all? NO!

Soils are designed to give up a certain amount of nutrients through natural decomposition of organic matter. Even if organic matter is at a low or undesirable rate, the natural processes will still do what the natural processes do. Interruptions in the cycle tend to come from over “conservation” more than any other issue. What I mean by this is; the soil is a living eco-system. The lawns and landscapes that grow in the soil are themselves living eco-systems. Nutrients are just pieces of the fertility puzzle.  A singular focus on nutrient “conservation” results in scenario that resembles the exact opposite of “eco-system conservation.”

A good example of this is someone who has low OM soils, perhaps sandy in composition, low CEC’s because of the soil type, and has a baseline of NPK that seems to be fairly consistent.  This person follows all the recommendations of his Chemical / Fertilizer Sales Rep., but sees a steady decline in overall health of his turf. The recommendations are always the same, 4lbs of N, 2lbs P. 1.5lbs K. This recommendation doesn’t change, yet the results get worse and worse. The answer from the chemical / fertilizer rep: Add on sales!  You go back to the field with more S, more Fe, more Mg… the list goes on… The result:  the soils and the soil test are still very consistent with what they’ve always been… The only thing that changes is your bank account balance.  What’s happening here? You had good intentions. The effort to conserve “nutrient availability” was made but the desired results weren’t achieved.  Apparently, nutrients are not more available the more they are added. This is the common mistake yet sadly has been THE CORNERSTONE OF TURF CARE for decades.

A soil test should show you what is needed to make more nutrients available to your plants so that each feeding hits maximum utilization. As I’ve stated before, show me pH, OM, and CEC and I’ll give you a healthy plant. I don’t really care what else is in the soil beyond that because every plant nutritional need will be dictated upon those items. I don’t need the information of how much N to put down if I’m building soil. The more N I put down, the less the soil builds! I really don’t need to see how much P is there, or K for that matter. The plant will only take what it needs when it needs it. So again, if I continue to allow for natural decomposition of soil life, I will never run out of either of those.

Are there instances where you may need to add a nutrient to buffer another? Yes. But, this typically presents as a persistent problem in a geographical area, not an isolated one. Florida has a great and easy example of this, Calcium. It’s too much and it’s everywhere. It’s tying up everything all the time and people still don’t know what to do about it… better get another soil report. Blah. Calcium can be loosened with heavier applications of Potash. Potash should be a go-to item for all operators in the state of Florida. And for the most part, it is… they are just using a form that makes it worse! Generally, the most widely used form of potash in the world is MOP (muriate of potash). Why? It’s cheap, very cheap and it’s 62% potassium. Sounds okay you say? Well, it’s also pure salt. MOP should not be used on salt sensitive crops, where soil salt levels are high or increasing, or where irrigation water has high salt levels. Last time I checked, salt levels in soils under typical fertilizer programs are rising, causing a decrease in microbial activity, causing water to leach away from plant roots, (the very thing potassium is supposed to prevent)  and by the way, doesn’t excess salt kill plants? Yes it does. Of course there are exceptions, but coastal native plants are rarely found in Wisconsin.

The sad truth of the industry: The recommendations made by the soil testers and the chemical / fertilizer sales reps are about product sales; nothing more, nothing less.  Just as the lawn care company mentioned in Lawncology® 2, they are financially rewarded by facilitating problems for which they just happen to sell a solution.  Is it really that sinister though?  Yes and no.  I don’t know if anyone has ever noticed that the lawn care product distributors selling fertility products are the ones that sell the controls. It’s funny that they go hand in hand like that. Make no mistake, the more products they sell that cause problems, the more money they make.  However, it is important to note that they are dealing with the information that they have and the universities and the companies whose product they carry have provided it. It is also important to note that there are many service companies that like to create problems for profit.

If lawn fertility plans were made correctly, the budget for products used should be 65-75% fertility building nutrition, 25-35% controls; not the other way around. Let’s make a pact that we will not treat lawns like a crop. If you feel the need to do a soil test, talk to us. We’ll help you make sure to get the testing information needed to make good fertility decisions. Let us teach you how to create sustainably healthy lawns rather than perpetuate an unhealthy methodology that only hurts our industry, our environment, and our customers.

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