Farmers in Hardin County Are Making a Difference on Soils that Are Prone to Flood
Karl and Alex Forsbach farm in Hardin County. They are our 31st Profiles of Soil Health Heroes. They farm below Pickwick Dam near Savannah, Tennessee. The lands are unique in that they may flood from time to time when the Tennessee Valley Authority must flood the terrace soils due to excess rain. Talking to farmers in the area, there are resistances to no-till and use cover crops due to the threat of seasonal floods that will move crop residue in large piles. Flood threats also can drown out cover crops or crops too for that matter. I first visited the Forsbachs and discussed their unique situation in April of 2015. I met Alex my first month as the Soil Specialist for Tennessee Association of Conservation Districts (TACD) at the Milan No-till Field Day, July of 2014. We discussed soil properties that factored into the rainfall simulator showing good infiltration and less erosion. We discussed cover crops and no-till. He invited Mark Roberts, NRCS District Conservationist, Savannah, Tennessee and me to their farm.. We finally were able to meet with him and his father, Karl in April of 2015. They had been using some vertical tillage to anchor the residue hoping to slow the movement of residue when flooding occurs. I discussed the effects of any tillage. Tillage destroys aggregates regardless of depth and leaves a restrictive zone or tillage pan that restricts infiltration. Live roots and soil biology aggregates the soil which leaves voids in the soil that leads to a granular or sub-angular blocky soil structure. This structure is like marbles in a glass. They fill up the space in the glass, but there are voids or space for air, water, and roots to freely move. That what roots and soil biology do for the soil. Tillage will destroy aggregates and consolidate the soil causing soil crusts and limited infiltration.
We discussed them going to permanent cover crops with their crop rotation on our visit in 2015. I had the privilege of revisiting them with Mark Roberts and David McMillen, NRCS State Soil Scientist, Tennessee on March 9, 2017. The day we visited the farm, we were blessed with 72 degrees of early Spring-like temperatures. Karl Forsbach grew up in Germany. He moved to the United States and bought farmland in Hardin County. Alex, his son, attended Mississippi State where he obtained a degree in Agriculture and a Master's in Business Administration. They farm together about 3,300 acres of corn, soybeans, milo (grain sorghum), and wheat. They irrigate approximately 900 acres with central pivot system. They plant corn and milo on 30" rows, and soybeans on 15 " rows. Wheat and cover crops are drilled.
Their no-till planter has a lead coulter, seed firmer, closing wheels are combination of one spike wheel and one rubber wheel. No-till drill is shoe type drill. Their fertility program begins with annual soil testing on hybrid grids based on soil types and 5-acre grids. They apply nitrogen at planting DAP plus potash. They side dress corn at V2-V3 and Milo at 4-6". Side dress nitrogen is 28-30% liquid plus sulfur. On the irrigated corn and milo, they fertigate with two additional treatments. They apply by soil test. They do not use variable rate application.
As I said in my introduction, they no longer use any tillage. Everything is no-tilled. They are currently in year three of cover crops plus two additional years of wheat for grain, so five years of a winter cover. The first field we looked at is by their testimony, their worst field. It is known as field 15. It currently has radishes, turnips, rye grass, vetch, and cereal rye on it. The cover crops were about 6" in height on March 9, 2017. They drill all of their covers after harvest by October 15. They use rye grass because it handles the flooding the best. This field was flooded in past years in January for 10-14 days. The rye grass was dormant at the time and survived the flood. As we dug in the field we noticed granular structure and some sub-angular blocky structure which shows soil biology is aggregating well. In contrast, when I was here previously, April of 2015, this field had platy structure. The structure had really changed favorably in about two years of using covers and no-till. They indicated the original soil organic matter (SOM) measured < 1%. Now the field averages 2.5% SOM.
David McMillen mentioned that they are mimicking the forest with multi species; they will exceed natural SOM in this system. Natural woods are about 3% SOM. We expect these agroecosystem fields to exceed 4% one day. Field 15 had height of multi species of about 5-6" with temperatures at 72 degrees. We also noticed the three fields that we visited had no standing water, although they had received substantial rainfall in the last few days. Other adjacent field that are under tillage had standing water. One of the earlier responses from no-till and cover crops is better infiltration. Also having plants with a healthy root system take up excess water. David McMillen said that we you clear woods from a wet soil, it gets wetter. Soil biology through decomposing organic material will aggregate soils through the slime exuded from earthworms and other soil biology. The fungal mycorrhiza forms as soils are not disturbed and soil material is constantly available for their consumption. The food web polices themselves. That is there is good diversity in the food web that promotes a balance of organisms and reduces harmful organisms that are common with monocultures. The food web cycles nutrients more efficiently as well as aggregates soils. No-till and cover crops promote increases in numbers of soil biology as well as quality due to diversity. That is why we promote multi species in cover crops.
The other two fields that we looked at were even better. They had darker surface colors. The structure was more granular. There were many earthworms on every shovel full of soil. I asked them when they killed their cover crops. The Forsbachs desiccate at about knee-high. They kill about two-weeks before planting, and plant when cover crops are crispy. Karl and Alex use two passes of Round-upTM and one time with GramoxoneTM. They use some ammonia sulfate in Round-upTM. The Forsbachs are interested in the future of acquiring a roller/crimper and leaving the cover growing longer and planting into rolled cover. I asked them to summarize their benefits. Of course, we've already noted better soil structure and better infiltration. There are much more earthworms, better weed control, their cover crops stands are better each year. They said the dry fall actually helped them establish a better cover crop. Karl and Alex still spray fungicides on corn. They scout soybeans and only spray as needed. The Forsbachs are saving $17.00 - $25.00 per acre on acres they do not spray fungicides. They see more benefits in dry years with yield stability when other farmers are suffering yield losses.
I asked them what would they say to farmers not no-tilling and using cover crops. They said farmers should use side by side comparisons in plots. It takes extra management to add am variable such as cover crops. Farmers need to be committed to handle that variable. Alex said he would have liked to heard my recommendation of plant green or crispy when they started out. They experimented and found that they were most comfortable with crispy residue to plant in. So, they like killing covers 14 days prior to planting. He said farmers beginning should know when to kill and to plant. He does not use their row-cleaners much. They are on the planter but with little down pressure.
The Forbachs farm in a unique area with their fields prone to flooding. Most farmers utilize tillage to anchor the residue to attempt to reduce the crop residue from piling up during floods. The result of tillage is less quality of soil. The Forsbachs have gone against the norm and have committed to continous no-till and palnt multi species cover crops or wheat for grain keeping the soil covered with living plants. They have not only improved the soils but have saved in input costs with reduced fungicides and herbicides. With their efforts, the soil is drastically improving along with their profits. I hope more farmers will follow their example.