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Treat the Disease, Not the symptoms
by LuAnn Rolling, District Conservationist

We know that healthy soil is bursting with life, it is just that most of the life is at the microscopic level so we can’t readily see it. A single teaspoon of soil is estimated to include one billion microbes including bacteria, fungi, nematodes and more. All of these microbes serve a purpose in a very complex ecosystem that we cannot see.

We have heard some bad things about some of the microscopic life. The word “nematode” is considered bad. In truth the “bad” nematodes make up 5 percent of the nematodes and the rest are doing “good” things like eating bacteria and excreting plant available nitrogen because of it.

There is a microbe called mycorrhizal fungi which forms a relationship with certain plants, such as corn, to exchange sugar the plant makes for nutrients and water, particularly during times of drought.

The reality is there really aren’t “good or bad” microbes, they all fill a niche.  The problems arise when the natural system of checks and balances is upset.  While we typically try to figure out what pest is causing the problem and then try to eradicate that pest, what we should be asking is, “What caused the imbalance and are we doing more harm than good by throwing pesticides on?”

All this time we’ve been trying to kill a certain weed or pest we’ve been treating a symptom and missing the disease. There are many scientists who believe that severe flooding, erosion and even climate change are only symptoms and the true disease which is biologically degraded soil.

How does anyone know if their soil is degraded?  One of the easiest to gauge would be water infiltration.  A biologically healthy soil can absorb over 12 inches of rainfall in one hour.  The average cropland soil in Iowa can absorb about ½ inch of rainfall per hour.  

If the disease really is our soil, how do we start to treat it? There are five general principles that mimic nature’s processes.

First, minimize soil disturbance, including chemical and physical disturbance. When plants are supplied with synthetic fertilizer they no longer send sugar to mycorrhizae. Later in the summer when plants need more water and nutrients the fungi aren’t present to deliver them. Also tillage breaks up soil structure and increases soil temperatures, killing microscopic life.

Second, keep the soil covered. Whenever we create bare soil mother nature puts a bandage on the problem in the form of weeds. Nature is trying to moderate soil temperatures, decrease evaporation, reduce compaction from rainfall and provide food for microbes.

Third, keep a living root in the soil for as long as possible by using cover crops and perennial crops. Living roots feed the microscopic life throughout the year.

Fourth, incorporate livestock into the system. Grazing animals help cycle nutrients. The key is to utilize the animals so they do not cause more harm than good.

The fifth principle is diversity. Nature does not believe in one or two crops year after year; that is a human invention. Diversity increases yields by decreasing pests and improving the health of the soil ecosystem.

We’ve spent a lot of time, and money, fighting with nature when nature already had answers to many of our problems. We need to remember the soil is something we have to nurture. It’s time we start taking those steps and get back to having healthy soil.