No Till Notes: 'Path to Soil Health'

After listening to various speakers over the past month at the no-till conferences I attended, it became pretty obvious that we are working with degraded soils on our farms and ranches. The soils we work with now are not the same quality of soil that was present when farmers and ranchers originally began production agriculture on this land.

The soil is lacking carbon, or organic matter as it is often referred to, when compared to the virgin soil our ancestors tilled for the first time when the sod was originally broken. I would estimate the majority of our soils have organic matter content, or carbon content, that is less than one half of the amount contained in the soil originally. The main culprits used in modern agriculture that have promoted the loss of carbon have been tillage, lack of a living root throughout the growing season and overgrazing. The good news is we now have the model that can begin to restore the carbon levels in the soil.

The path to soil health is really quite simple. To begin restoring soil health we need to alter our current modern production model. The current production model used on many farms is producing mono culture crops with tillage of the soil. Often these mono culture crops are produced many years in a row such as continuous corn. An even bigger detriment to soil health is a winter wheat/summer fallow cropping system where there is nothing growing in the soil for extended periods of time during the fallow period.

The path to soil health begins with the adoption of continuous no-till crop production practices. Minimizing soil disturbance is critical to restoring the health of the soil. Leaving the previous crop’s residues on the soil surface begins to rejuvenate the soil by feeding the soil microbes in the soil. These microbes begin to process the crop’s residues and start to build soil structure. The formation of soil aggregates begins with the excretion from the soil microbes which begin to build soil particles into stable soil aggregates. The microbes use these soil aggregates as their home. The aggregates also provide pore space for the infiltration and storage of precipitation.

The first step down the soil health pathway is to adopt no-till crop production practices. The next step is to add diversity to the crop rotation and eliminate long term fallow in the system. Adding diversified crop rotations to the system will increase the diversity of the soil microbes and the populations of the different soil microbes. I have soil sampled our long term continuous no-till crop production soils and compared them soils in a winter wheat/tilled summer fallow system. The soils on my farm have a much more diversified soil microbe population with bacteria, fungus, nematodes and protozoa all present in the soil. Conventionally tilled winter wheat/summer fallowed fields tend to be dominated by bacteria.

The soil in a continuous no-till crop production system with diversified soil microbes is able to cycle nutrients much more readily than bacteria dominated winter wheat/summer fallowed soil. These no-till soils also have better soil aggregate stability which provides the home to these microbes and allows for improved infiltration and storage of precipitation.

The no-till soils are a step in the right direction to improving soil health. We have noticed increased soil organic matter levels in our long term no-till soil. The increased soil organic matter levels improve the nutrient cycling by the soil microbes; improve the water cycling capability of the soil, and the carbon cycling in the soil due to improved soil health.

There are more steps to be taken down the path towards a truly health soil than no-till crop production practices can provide on its own. No-till production is merely a tool to use in the path towards soil health. No-till crop production has a limited ability to restore soil health.

Next week, I’ll take a look at the limitations to restoring soil health that a no-till crop production system on its own has and the necessary steps beyond no-till that need to be taken as we move down the soil health pathway.