Seeing the Positive Effects from Cover Crops in Dyer, County
Jesse and Danny Castleman farm in Dyer County and reside in Newbern, Tennessee. They farm predominantly hill-lands in the Newbern area. Their soils are mostly Grenada and Loring Silt Loam. Since these soils have fragipans, they tend to be wet when rainfall is plentiful and drought prone when dry. Jesse took over the farming operation from his dad, approximately two years ago. Jesse is our 33rd Profile of Soil Health Heroes. I visited the farming operation on June 7, 2017 along with Adam Willis, NRCS Soil Conservationist, Dyersburg, Josh Richardson, District Conservationist, NRCS for Obion and Lake Counties, Ryan Blackwood, NRCS Soil Conservationist, Dyersburg, Danny Castleman, Josh Phillips, NRCS District Conservationist, Dyersburg, Jesse Castleman, and Landowner, R.C. Owens.
Jesse produces grain crops with a corn and soybean rotation. He and his father began cover crops in 2014, predominantly for erosion control. Most of their fields are 2-5% slopes. The soils are from loess (wind-blown silt). They are highly erosive when left bare and tilled. Jesse and Danny learned a few years ago that no-till was the method to farm due to erosion potential on their soils. As earlier noted, the soils are drought prone when conditions are dry, so additions of SOM are essential for these soils to remain productive. Growing cover crops have added much more active soil organic matter or carbon to their soils. Historically, we have lost over 50% of our soil organic matter (SOM) or carbon. Carbon (C) makes up approximately 58% of SOM; and therefore, the terms will be used interchangeable. Keeping a plant growing is the best way to build or increase SOM. Green plants produce sugars or carbon as a result of photosynthesis. Farmers miss opportunities when they only grow one crop per year for 110 days or less. However, cover crops not only add diversity to a corn and soybean rotation, but also provide more efficiency of intercepting energy flow from the sun. Jesse is doing this by planting multi species cover crops annually. Also, multi species cover crops mimic nature with many species growing during the season instead of just a monoculture crop. The sheer amount of biomass grown in the cash crops and cover crops add significant carbon to the system which in turns feeds the soil biology in terms of quantity and quality due to the diversity. The soil biology provides better soil aggregation and nutrient cycling; thus, the soil health improves.
It is necessary for productivity to provide the essential elements. Jesse soil samples by zones, soil types and different slopes. He uses some variable rate application of lime and phosphorus and potassium (P and K). He also applies straight blend on portions of his farming operation. Jesse and Danny have applied chicken litter periodically on their fields the last ten years. The main factor for them is the availability of the litter.
They are in their third year of cropping behind cover crops. Their current mix consists of cereal rye, crimson clover, Austrian winter peas, Bob oats, and tillage radishes. They broadcast the seed the first year in the fall of 2014. Since then, they have used a drill or planter. They have used two methods of planting for their winter cover crops in 2015 and 2016, drilling after corn (7.5" rows), usually around the last week of September. Jesse and Danny use a planter (15" rows) after soybeans, usually the first week of October. They have noticed less weeds where drilled compared to 15" rows. Since they get better coverage with a drill, they plan to plant 100% cover crops with a drill this next fall.
Farmers can monitor soil changes by observation and by soil tests. Jesse has seen his total SOM hover around 2 - 2.5 %. Total organic matter is important but is much slower to respond than active SOM. Studies show that in soil degradation, we lose active carbon at a greater rate than other forms of SOM. In contrast when we restore our soil and SOM, active SOM recovers quickly followed slowly by slow to decompose SOM and finally by passive SOM or humus. The take home message is monitor total SOM, but know that positive changes are occurring before you see major changes in total SOM.
For example, water cycling returns or improves in a field fairly quickly by soil structure changing from a platy (horizontal plates) to a granular structure (crumbly). The granular to sub-angular blocky soil structure are like marbles in a jar. There is always pore space between each aggregate or marble, thus giving porosity or void space for better water infiltration. This happens in year one to two. Aggregation is not permanent. If plants are no longer present, aggregation ceases in less than a year. New aggregates are formed around roots and have a life of four weeks or so. We must keep plants growing to keep the soil aggregated which in turn means greater water infiltration.
Another benefit that Jesse is seeing is the increase of soil biology, earthworms were prevalent as we dug many samples in the field. You can also see activity on the surface with small insects, earthworm casts (worm manure) on the soil surface. All of these activities assist in carbon decomposition which aggregates soil and cycles nutrients. In year three, we see these evidences, but will need another year or so to see an increase in decomposition of previous year's crop residue. The Castleman's farm will show quicker decomposition the longer they are in this Last season of 2016 was unusual in that the drought followed by a very mild winter caused the growth of cover crops to be different. Some had lighter stands of grass but thicker stems. Follow that up with a cool and very wet spring, and that is the prescription for slugs. Slugs are in no-till fields and no-till with cover crop fields in 2017, especially in counties north in Tennessee. The best solution is dryer and warmer weather which we are now experiencing. However, slugs tend to damage plants that are slow growing due to weather conditions. Normally, they do not destroy stands but make the stands somewhat ugly. Again, hotter weather will prevent this. Farms with wetter soils and fragipan type soils where they are wetter during wet periods may experience this more so than well drained soils. Most controls are expensive and usually not very effective by the time you see the slugs.
As we have these different planting seasons, farmers tinker with planter attachments to establish good stands even in high and thick residues. The last thing we want to do is to till and destroy the good from a no-till system and cover crops. Jesse Castleman like many hundreds of farmers in Tennessee is staying the course in using cover crops.
I asked Jesse and his father Danny what are some benefits they are experiencing. They as well as the NRCS employees chimed in that water cycle has returned to the field. That is the water is being infiltrated much more readily due to active carbon accumulating and soils are better aggregated. As I mentioned earlier, they began this system due to erosion, so erosion has been reduced dramatically. They are also seeing much more earthworms. As I dug, I noticed the soil was easily penetrated by my shovel. Soils are softer and less compacted in a cover crop system. I also noted several earthworm casts on the soil surface. Another benefit mentioned by Jesse and Danny is weed suppression. They said mares tail that once was prominent in their fields is now non-existent. They also noted that pigweed (Palmer's Amaranth) was less prevalent. They both remarked that when they see run-off, it looks like drinking water, very clear.
Their herbicide treatment consists of Round-upTM and VerdictTM at burn down for both corn and soybean planting. In corn, they come back with AtrazineTM, CaprenoTM, and Round-upTM. They are saving at least one to two extra herbicide treatments. This amounts to 17.00 - $25.00 per acre. Normally they do not spray fungicides on corn. In soybeans, they scout and spray as conditions warrants it.
Their planter has a front-lead coulter. They used it at times, and when it was wetter they removed it. Their advice to others is start small, learn how to plant in residues. Try something different each year as you learn the system. Definitely, begin using multi species. They previously tried wheat, oats, and crimson clover prior to going to current mix. They plant corn at 29,000 plants per acre, soybeans at 160,000 on hill-ground and 120,000 plants per acre on bottom-lands.
They terminated their covers at about waist-high in 2015 and 2016. They planted green on a few acres in 2017 and planted those acres at approximately 60" plus in height. The remaining acres in 2017 were planted 14 to 21 days after termination of cover crops in approximately waist-high cover. The drought in the fall severely limited the legumes. Of course, the radishes winter-killed, so the residue now is predominantly grass. Jesse and Danny along with other farmers dealt well with drought and still had substantial residue from their cover crops. Farmers that are consistent and persistent will see the benefits from soil health as well as their soils being more productive which means more profit per acre. Farmers interested in technical and financial assistance to improve their soil health should contact their local NRCS and Soil Conservation District's office.