Tuesday, November 20, 2012

The Beginnings of a Paradigm Shift

By Dan Towery, SWCS President

There is a growing buzz about soil health, and I believe that this subject is going to be a game changer. I wasn’t taught about soil health in college (in fact, I was taught that one cannot increase the organic matter on cropland). However, things have changed since then. Back then, no-till was in its very early years of adoption, and if cover crops were planted, they were used as a green manure crop. When I was working as a soil conservationist with the Soil Conservation Service, if a grower planted no-till it was a major accomplishment. At that time, however, it was done as a one-year conservation practice. Continuous no-till was only being used by a small number of growers, and even fewer researchers were using continuous no-till. Rotational tillage (no-till one year and then full-width tillage for other years) was the norm. It was almost twenty years before I realized that it took continuous no-till to see improvements in soil properties. Most (but not all) researchers and those who provide technical assistance now realize that rotational tillage results in almost no change in soil properties.

The adoption of continuous no-till and a more diversified crop rotation (at least in the Great Plains) began the shift in thinking regarding soil health or soil quality. Over time, there was an increase in organic matter in the top most soil layer; infiltration, aggregate stability, available moisture holding capacity, pore space, and bulk density improved. The soil was functioning better, and growers were seeing a yield increase in dry summers. Growers then started planting cover crops to add some or even more diversity to the crop rotation, and the changes in soil properties came much faster and were even more pronounced. Scavenging or fixing nitrogen dramatically changed the nitrogen cycle. Also, the use of cover crop “cocktails” (mixes) started growing.

Due to these production advantages, soil health has become the buzz. It may not be prominent in your county or area yet, but it will be. Instead of just looking at the physical and chemical soil properties (as I was taught in college), the interrelationship with the biological properties is now emerging as a critical component of the soil functioning process. But it takes time to change the biology in the soil. It is complex and is affected by temperature and moisture (remember it is a living system). Just as we can’t see germs and viruses, we can’t always observe the actual bacteria, fungi, or other soil critters, but they are there. Researchers will sort out the scientific aspects regarding soil biology over time. Meanwhile, more and more farmers and farmer advisors are seeing the results of an improved soil. They are seeing consistently higher yields in some years because they are making their soil more resilient. And a healthy soil is a critical step in order to improve water quality and to reduce carbon dioxide emissions.

The Natural Resources Conservation Service recently launched a soil health campaign that can be viewed online here. The Indiana Chapter of the Soil and Water Conservation Society held a soil health workshop on November 16th, and two cover crops conferences will take place in Iowa and Illinois this winter. Take a look at these and other events and become involved in learning what soil health is all about.

This article first appeared in the November 2012 Conservogram newsletter.

1 comment:

Physicus said...

I could not agree with you more Dan. We are beginning to understand the soil for what it truly is; a biological system. We can now improve soil health, be sustainable and profitable at the same time. We must restore the capacity of the soil to function if we are going to make any progress at reducing the symptoms of erosion and nutrient loss into surface and ground water.