Progressive Soil Conservation Practices Lead to Soil Health Improvement in West Tennessee
Mark Carroll, NRCS District Conservationist, Dresden, Tennessee and I met with Scotty and Jack Ogg on October 22, 2018. The Ogg farm is our Profiles of Soil Health Heroes number 48. Scotty and Jack farm in Weakley County. Orren (OP) Parker, Jack's nephew also farms with them. Scotty and Jack shared that Scotty's grandfather was old-school conservative farmer. He would not try cutting edge technology. Jack told me that his dad would not use fertilizer. Jack, on the other hand, was aggressive and believed that you invest in modern equipment and invest in land. Jack understood stewardship. He began no-till in the 1970s. Scotty added that his dad had invested in bermuda grass waterways and sediment basins to control gully erosion.
As Scotty joined the operation, he no-tilled but other than wheat in the crop rotation, had no cover crops growing in the winter. West Tennessee has loess soils that are easily eroded. Even though most of their farming operation is gently rolling, erosion is a major concern. Scotty shared with me that it was common up to 10 years ago to use a field cultivator to work in the annual rills. No-till alone was not preventing erosion. Besides erosion, Scotty and Jack were concerned about soil organic matter decreasing which correlates to loss in yields. They also were concerned about water runoff and wanted more available water holding capacity. Another concern was weeds, especially Palmer Amaranth (pigweed) and Mares' tail. All of these concerns led them to add cover crops to their crop and pasture operation.
Scotty and Jack have a diverse operation. They have beef cattle, swine, and crop rotation of corn, wheat, and soybeans. In addition, they grow crimson clover and oats for seed to sell for cover crop seed. The tandem also grows Austrian winter peas as single species cover crop. In addition to the before mentioned single species for winter cover and seed production, they also grow oats and red clover for two species cover crop mix. They recently added six multi-species mix on certain fields consisting of oats, crimson clover, Austrian winter peas, vetch, purple top turnips and Daikon radishes. They also grow winter oats for horse hay and some black oats after corn. When developing a cover crop mix, it is essential to consider carbon to nitrogen ratio (C:N). Most recommendations from NRCS are 28:1 to 32:1. The range is important to increase carbon to the soil and balance to provide nitrogen to upcoming cash crop. The C:N ratio is managed two ways. One is the mix with a balance of grasses, legumes, or brassica family. The second way is height of termination. The more mature a plant is toward fruiting correlates more carbon to nitrogen ratio.
Scotty and Jack Ogg terminate their covers 14-21 days prior to planting cash crops. Covers are killed at thigh to mid waist high. Crops are planted in standing covers. The Ogg operation will use glyphosate, Selecttm, and Dicambatm in their burn down herbicide application to terminate cover crop mix.
Scotty's goal is to have 100% of the fields in a winter growing crop or cover crop. This last year, 1,200 acres were covered except 100 acres. Most of their winter cover crops are planted with a no-till drill which makes up approximately 75% of their cover crop acreage. The wheat-double cropped soybeans have covers aerial seeded by plane which consists of approximately 25% of the cover crop acreage. They no-till drill covers from September 11 through approximately October 12th. Their aerial seeding occurred between September 29 - October 1 before soybean leaf drop and harvest.
On some of their pastureland fields, they no-till drill rye grass for winter grazing. They have a field that is fairly wet, that they lightly disked and then plant corn-soybeans in a rotation. I discussed to them the possibility of no-tilling and using annual rye grass.
They typically grow group 2.9 - 3.8 soybeans and scout for disease pressures and normally use fungicides on early beans. On their 4.2s to 4.9s, they scout and usually do not use fungicides. For corn, they rarely use fungicides, but will if scouting calls for it. Their nutrient management consists of soil testing in 2.5 acres of grids every three years. They apply lime, phosphorus and potassium by variable rates.
Scotty and Jack have shown some typical benefits of using cover crops. They have noticed some yield effects due to soils are more easily to plant, soils less hard. They have experienced much less noticeable erosion, and much better water infiltration. They experienced less detrimental drought effects due to better water holding capacity.
Scotty and Jack understand that building carbon in their soil is the key to making their soils function better. They have discovered, as well as many other farmers have, that keeping a live plant/root growing is the key to increase carbon. Keeping a green plant growing intercepts the energy flow from sunlight through photosynthesis. The process transforms sun energy into sugars or carbon into the plant. The plant trans-locates carbon from leaf to stem to roots. The roots leak 5-20 percent of carbon produced by photosynthesis to feed the soil biology. The biology, in turns, converts plant material to soil carbon (soil organic matter). Through these conversions, soil is aggregated improving water infiltration, cycles and stores nutrients. Another key is to minimize disturbance such as tillage to protect carbon losses. Also, need to keep the soil covered, for soil temperature management, and to provide food and habitat for soil biology. Finally, diversity is important for soil biology. Growing different crops and well as diverse plants in cover crop mix will correlate to diverse soil biology. Diversity can improve yields and reduce disease pressures.
As we were digging in the soil, we saw better soil structure, more earthworms, and smelled good earthy-soil aroma meaning more biology activity. Scotty and Jack Ogg are progressive in their use of cover crops to control erosion and improve soil health. They are not just reducing soil degradation, but now are improving how the soil function. Farmers need to improve the soil's heart, and that is soil carbon or soil organic matter. For soil health assistance, contact your local NRCS and Soil Conservation District's office.