No Till Notes: 'Improving our productivity, part 2'

Last week I talked about the loss of soil health in our traditional winter wheat/summer fallow cropping system that has been the predominant system used by producers over the past several decades. In terms of soil health this is probably the most detrimental crop production system.

When I have listened to experts in the field of soil health talk at conferences over the past several years there are a few key components to restoring soil health. The soil needs residues on the soil surface to protect the soil from wind and water erosion. These residues also feed the soil microorganisms. Tillage systems used to manage these residues destroy soil structure and soil aggregation along with the environment for soil microorganisms.

Good soil health requires a living root system growing in the soil for as long as possible during the growing season. Living roots feed the soil microbes. Living roots also decay and are a key component to building soil organic matter along with the decaying of the residues on the soil surface.

Good soil health also requires a diverse mixture of plants growing in the soil. Undisturbed native prairie has many diverse plant species, both grasses and legumes growing together during the growing season.

A traditional winter wheat/summer fallow cropping system with tillage goes against all the principles required to build and maintain soil health. In order to start improving the health of the soil we work with and depend on for our livelihood we must change our management practices.

The first step is to adopt a no-till cropping system. This is only the first step and must be followed by adopting a continuous diverse cropping system. On our farm we now use a winter wheat, corn, field pea crop rotation on our dry land acres. We have a cool season grass in winter wheat, a warm season grass with corn, and a cool season legume with the field peas.

This crop rotation has worked well for us over the past several years and I think we have improved the health of our soil over the past 20 plus years of using a continuous diverse no-till cropping system. We have seen our organic matter levels increase significantly over this time period. Our organic matter levels have increased from 0.6 percent organic matter when we first adopted no-till crop production to levels of 2.3 percent organic matter in our soil now.

Our soil performs better now with these increased levels of organic matter. NRCS tested the water infiltration rates in our soil and determined our soils can infiltrate 4 inches of moisture in an hours’ time without runoff. Traditional winter wheat/summer fallow infiltration rates were much lower in the .5-1 inch range. We are better able to store this water in our soil with increased water holding capacity due to improved soil aggregation. The improved soil aggregation leads to more pore space in the soil which can store more water.

With the residues of the previous crop on the soil surface we are able to lower the soil moisture evaporation rates which allow us to store more moisture for the crops we produce. All of these improvements lead to better utilization of the moisture we receive and improve our water use efficiencies which leads to higher yields in our crops.

I feel we probably have reached the highest soil health possible over our long term no-till crop production system. I don’t think we can improve the health of our soil in our environment any more than what we have achieved unless we change our cropping practices to focus more on improving soil health. Even after 20 plus years of a diverse continuous no-till cropping system on our farm I feel there is more we can do to improve the health of our soil and how well our soil performs.