Farmer from Benton County Increases Moisture in Gravely Soils by Growing Cover Crops
I visited the farming operation of Brian Inman on June 28, 2018 along with NRCS District Conservationist, James Woodall. Brian is our Profiles of Soil Health Hero Number 45. Brian farms predominantly in Benton County with a few acres in Decatur County. Brian's grandfather was a share cropper. His dad moved away from Tennessee for work, but moved back to Tennessee in 1960s and began farming. Brian began farming with his dad as a boy and teenager. Brian farms now with his brother, Wade Inman. Brian and Wade worked the ground originally as most farmers did during that time frame. They began experimenting with no-till in the 1990s. Brian previously worked at local Truck Service Center and farmed part-time for many years. He became a full-time farmer in 2002. His farming operation is approximately 2,500 acres.
Brian said that they converted from tillage to no-till due to labor, was easier to plant with more moisture, and to reduce erosion. His planter is an IH vacuum planter with no coulter with lead disk opener. He said it is essential to frequently check the bearings and to keep the disk opener sharp. He uses floating Martin row cleaners. The key, Brian says, is to barely see where row cleaners have been. Too much pressure results in bare soil. Bare soil loses function. On wet soils, he uses a very light pass of Philips harrow to lift crop residue and careful not to disturb soil. Brian uses Yetter closing rubber wheels for firming seed bed.
He samples every three years by grouping his soils; in addition, he runs Veris Electrical conductivity measurements. Besides nitrogen, Brian applies phosphorus (P), potassium (K), and lime by variable rates. For corn, he applies starter fertilizer, 5 gallons per acre of 9-18-9 with micro nutrients when called for by analysis. Brian applies 80 units granular urea at planting. He later top dresses 100 units of nitrogen (N) based on weather but near v-4 to v-5.
Brian farms near the Tennessee River. Soils range from slightly sloping to sloping. The soils contain some gravel. The first farm we visited is called the Cox farm. Brian said this farm has been no-tilled for approximately 25 years. He and his brother began planting wheat and crimson clover cover crops around 2012. They continued that mix until the fall of 2017. They began a multi species mix of 5 species: cereal rye, wheat, crimson clover, forage radish, and purple top turnips. Brian uses a spinner truck to broadcast the cover crops, usually in mid-September after corn, and mid-October after soybeans.
Brian said that Mr. Harold Cox, the owner began using no-till in an unique sequence. He began in a garden, where he tweaked his technique, and noticed better yields, especially in dry seasons. Mr. Cox proceeded to no-till his crop fields. Brian mentioned that the area adjacen to Tennessee River receives more intense rains over the last few years. This year fifteen inches of rain have fallen since planting the Cox farm. He said with the cover crops and no-till there were challenges with that much rainfall, but if they were still tilling the land, the crop would have been lost.
The Cox farm had just received 4" of rain a week prior to our visit with 0.2" the previous night. The corn had a good healthy color and was tasseling. James Woodall and I examined the soil; we found granular soil structure which provides excellent voids or pore space for water and air movement. When digging in a conventional tillage field, one will normally find strong platy soil structure or no structure at all. Even though no-till functions better than conventional tillage, it normally shows weak to medium firm platy soil structure. Platy soil structure has stratified plates that restrict or slows water infiltration. Conventional tillage will show a tillage pan at point of tillage regardless of implement used. On the Cox field, the granular structure is the result of 7 years of cover crops with last two being 5-way mix. As we dug, there were earthworms in every shovel full of soil due to the excellent soil moisture. There was inherent gravel in the soil. Again, if they were tilling, more gravel would be brought to surface. We also noted a medium-earthy smell in the soil indicating healthy environment for actinomycetes, a colony growing bacteria that mimics fungi in some ways. Actinomycetes excrete organic compound called geosmin. That is the earthy aroma that we smell in healthy soils. We also noted many earthworm casts and bio pores showing healthy soil biology. The previous crop residue was beginning to break down. Tillage destroys cover and soil aggregates which are the food and habitat for many soil living organisms.
Brian generally farms corn-soybeans. In some cases he will grow soybeans two years in a row. We checked two fields with soybeans after soybeans. These two fields have only had two years of covers. We could see much less in soil health indicators. There was good residue from cover crops, but basically no structure. This shows the need for more carbon in the soil which will take more years of cover crops and no-till. We found no restrictive layer with shovel. The smell was a weak-earthy smell. There were no earthworm casts.We did find some earthworms and bio pores. Farmers will see more results each year they continue no-till and cover crops. Soil health will improve in time.
Many of the other fields that we examined showed similar patterns. One field that had no cover had higher resistance as we dug with shovel, showing some compaction. Another field with good cover in its 2nd year of a 5-way mix had no resistance digging. It had good earthworm activity but lack other findings compared to Cox field that had been in 7 years of cover crops. Fields that have hard compacted soils became that way due to tillage and winter fallow. Tillage is not the answer to break compaction. Continuous plant growth with growing roots will increase carbon resulting in improved soil structure with no compaction.
Brian plants in standing cover crops. He normally plants corn in mid-April usually 14 - 21 days after termination of cover crops. He did roll and crimped one area of one field where rye became excessively high.
Based on the findings of Brian's fields, one can easily correlate better soil structure and soil biology to the amount of time in covers and no-till. If farmers begin farming fields that have been tilled, expect three years to see notable differences with slight increases in infiltration after first year. Fields that have been in no-till will take less time to improve than tillage fields. I asked Brian to share with us what benefits he had observed. He began with pesticides. He scouts for fungicides and generally does not apply any fungicides on early corn. He always sees economic benefit to spray beans as needed during the season and sprays beans annually. He sprays his later planted corn as needed, but not always, like his soybeans. He has not yet seen a need for change in his pesticide application, nor has he noted ant savings in nutrients. He did say that pH was very stable, especially in fields that had been in covers the longest. He said P and K are about the same.
He went on to list benefits which included more noticeable moisture during growing season, less drought stress on soybeans, and soil is fluffier and easier to plant. He also stated there were more earthworms, earthworm casts, better water infiltration, and less erosion. He emphasized that erosion is near nothing compared relatively to farming prior to cover crops.
Brian noted average savings on herbicides of approximately 10.00 - 15.00 per acre. He said on the fields that have been longer in cover crops had greater savings. We credit the heavy residue that chokes out weeds and some allelopathy that is natural chemicals that kill young small seedlings. In his best fields, he sees less mares tail and pig weed. During cooler wet springs like 2018, he will have to use his normal prescription. Otherwise, he is reducing some residual herbicides due to weed suppression from cover crops.
As my visit ended with Brian, I could sense the enthusiasm that he had toward improving soil health. Brian knows that he could not continue farming without improving his soil. He is following the four principles of soil health: keep the soil covered, reduce tillage disturbances, keep roots growing, and add diversity. All of these have and will continue to add soil carbon, increase quantity and quality of soil biology which will increase the functionality of the soil. Brian knows that better soils mean better crops, and better profits.