Conservation Tillage Systems in the Southeast

Stanley Walters, Gallion, Alabama

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Editor’s note: This case study was updated in 2018.

Stanley Walters farms 6,000 acres of corn and soybeans in the Black Belt region of Alabama in partnership with his son Clay under the name of Walters Farming Company. The farm headquarters is in Gallion, located seven miles east of Demopolis, and it includes locations in Hale, Marengo, Dallas and Perry counties. Walters is a native of Linden, Ala., and a 1977 graduate of Mississippi State University. After graduation he began his farming career farming cotton on the Coastal Plains soils between Linden and the Tombigbee River. The continuing loss of Coastal Plains land to pine tree production, crop predation by whitetail deer and the need for better efficiency forced him to begin farming in the prairie regions of the county soon after. The crop mix on the farm has evolved and will continue to evolve: at one time the farm had 3,200 acres of cotton, and today it consists of 5,000 acres of corn and 1,000 acres of soybeans. The farm has 2,160 acres irrigated by center pivot. All farm acreage is under some form of conservation tillage.

What do you consider to be the biggest challenges in farming Blackland Prairie soils?

Blackland Prairie soils of Alabama and Mississippi are particularly finicky. After farming this land for 40 years I am yet to discover a simple solution to the complex riddle that is the property of these soils. Fertility, while generally good, is complex due to the high cation exchange capacity, and high pH is a constant issue, especially with some nutrient tie-ups due to excessive levels of calcium. Soil test results are always perplexing and soil fertility decisions on these soils are more akin to an art than a science. The good moisture-holding capacity of these soils is a big plus, but it has to be measured against their poor internal drainage. Poor drainage coupled with this region being a high rainfall area creates severe access problems during winter and spring. The sticky/clayey nature of the soil when wet creates problems with spring tillage. While fall tillage works best from an access and seedbed tilth point of view, it will create an erosion hazard. The simplest solution to erosion, no-till, is fraught with sustainability issues, and cover crops, if utilizing the most common cultural practices, can result in devastating results in a wet spring. Shallow spring tillage is an option if the ground is dry enough but is still subject to extreme risk from a seedbed moisture and timeliness standpoint.

What conservation tillage techniques work best for you?

The most universal tillage practice we use behind corn is to run a disk extremely shallow (less than 1 inch) and extremely fast (10 miles per hour). The ground needs to be dry and the tool has to be set to perfection. We run this twice at opposing angles. We are mainly cutting and sizing the stalks, knocking off any ridges and filling tracks. We don’t create very much loose soil, so even in a big rain event there is little soil movement. The surface is usually covered fairly uniformly with residue that keeps us in compliance as far as our highly erodible land (HEL) conservation plan with the NRCS. As far as the soil profile is concerned, this is no-till—the planter opener will be going into undisturbed soil. The biggest issue has been if your first moisture in the fall comes as a big rain event the stalks will float around and create mats and bare patches. This situation will usually require another trip to “fluff and spread the residue” whenever it is dry enough. I prefer to no-till into standing corn residue (one year only) if we have no sprayer, grain cart, combine, pivot or planter tracks. The soil is in the best condition if it can be left alone for a full year. Behind soybeans I prefer to plant no-till into crop residue if possible or to use a small-grain cover crop if we have to correct tracks, as soybeans do not leave enough residues after even the light disking to protect the soil and stay in “compliance.” We reshape and seed all of our ephemeral drains every year; a permanent fescue cover usually results in two gullies at every drain over time.

What are the biggest problems that you have encountered with conservation tillage techniques on Blackland Prairie soils?

  1. We have not been successful using continuous no-till on prairie soils. The soil surface will become so unruly and riddled with rill erosion and equipment tracks over time that it will be rendered un-farmable and will actually suffer more severe erosion than if it were farmed using full tillage.
  2. We have and will continue to utilize cover crops to protect soil that has to be worked but has insufficient crop residue. However, we have suffered terrible consequences when proper management and precautions were not observed to prevent excessive cover from establishing itself. This soil has poor internal percolation; if the sun and the wind can’t get to the soil it will not dry and thus can’t breathe.
  3. The size and weight of modern agricultural equipment creates tracks and thus “heaves” or “bulges” on the field surface require correction. This is not to be confused with “ruts” as might be created when the ground it wet.

What are the biggest advantages, if any, of conservation tillage on these soils?

The biggest advantage to conservation tillage has been timeliness. We are generally able to plant much earlier than if the soil has been fully worked. The soil profile is as firm as it would be if no-tilled, which resists erosion and waterlogging and is more capable of supporting machinery when wet. Our horsepower usage and labor are less because we don’t do much to the soil to get it into condition.

What are the biggest problems with conventional tillage (e.g., moldboard plowing, disking, chiseling, etc.)?

The horsepower requirements, as well as fuel and labor, are much greater; the erosion hazard is much greater; and the risk of being too wet to plant or harvest in a timely manner is much greater.

What are the advantages of conventional tillage?

Conventional tillage will give you a more consistent planting surface, will reduce the risk of nutrient stratification and should reduce the risk of volatilization of urea-based fertilizers.

Do you use subsoiling under the row? Why or why not?

We do not subsoil. Our soil naturally resists compaction. Upon the advice of an agronomist we ran in-line subsoil plows on 1,000 acres in 2016 and saw no advantages. Not wanting to make a determination based on one experience, in 2017 we subsoiled 100 acres with the same result. So, in 2018 the plows stayed in the shed.

Do you have any other comments or ideas about conservation tillage on Blackland Prairie soils, or ideas for future research?

The problems we have encountered with the prairie soils have remained constant. How we react to them is in a state of constant change. Rotation has always been a tool I have used, and I prefer to utilize a corn, wheat and soybean rotation. However, the profitability of wheat became untenable and we had to drop it from our mix. The combination of deer and iron-deficiency chlorosis are severely limiting soybeans as an option. Cotton may be an option in the future but restrictive NRCS compliance regulations in regard to utilizing a raised bed are why we left cotton to begin with. After a wet harvest, such as we encountered in 2017, we do have to deal with areas in the field with some compaction. It’s a shallow compaction that should be short lived, but it is impactful to yields just the same. Cover crops will be a big part of farming these soils in the future, and I have requested that Auburn University begin a long-term research project at the Black Belt Experiment Station in Marion Junction, Ala., to study methods, varieties, rates, timing, etc. I understand work has already begun. I also requested research work to be done concerning waterway vegetation management. Waterway design and management may be the single biggest impediment to sustainable cropping systems in the Black Belt.

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