Coffee County: Planting into High Biomass Cover Crops
Adding Nine Species of Cover Crop Mixture to Improve Soil Health
Mike Hubbs, TACD Soil Health Specialist
Jamie and Ray Weaver
The eighteenth in our series of Profiles of Soil Health Heroes is Jamie and Ray Weaver from Coffee County. Ray Weaver has been farming since 1971. Ray has been president of Tennessee Association of Conservation Districts (TACD) for the last five years. Ray is a leader in the state for conservation of natural resources. Ray is also Chairman of the Coffee County Soil Conservation Board of Supervisors. Jamie, his son, has been farming with Ray since 2002. Jamie has his Bachelor of Science degree in Animal Science and a minor in in Agricultural Economics, both from the University of Tennessee in Knoxville, Tennessee.
I visited with Jamie along with the Natural Resources Conservation Serve (NRCS) staff of Coffee County, Adam Daugherty and Allen Willmore on April 4, 2016. The Weaver farm is quite diverse. They farm approximately 8 acres in grapes, 600 acres in row crops, 125 brood cows, and direct sale on beef, retail pork, 200 finishing pigs, direct sale, 20 acres sweet corn, and less than one acre in pumpkins. They plan to build a high tunnel and produce strawberries in the near future.
Their grapes are on 8 X 12 spacing, vines are eight feet apart in rows and rows are 12 feet apart. Grass or weeds grow between the rows. Vegetation is controlled only near grapes during the grape growing season. Jamie plans to plant crimson clover in rows during winter. His sweet corn is followed by some pumpkins that will eventually expand to more grapes. Cover crops are planted after sweet corn and pumpkins. Both crops are no-tilled in the cover crops.
Ray Weaver bought a no-till planter in 1975, and has experimented with reducing tillage since the mid-70s. They continued reduced tillage as technology of herbicides, planting equipment, and plant genetics improved. They have not tilled in approximately 20 years, other than some minor tillage in one field in 2005. Their current operation is corn followed by soybeans using no-till technology. Jamie said they began multi species cover crops in 2014 to diversify their soil biology which Jamie refers to "their bugs." The nine species cover crop mixture consists of 13 lbs. oats, 20 lbs. Cereal Rye, 20 lbs. triticale, 4 lbs. hairy vetch, 5 lbs. crimson clover, 0.25 lb. canola, 1 lb. radish, 0.25 lb. turnips, and 5 lbs. Austrian Winter Peas. Jamie says he changes some of the species in each field but always strives for 7-9 species. He says they always want Cereal rye, crimson clover, and vetch. Jamie said that besides the diversity of "the bugs" there is an increase in beneficial insects. Currently, 100 percent of their row crops are in cover. Their later seeded fields have less species but are in cover. Jamie wants every field to be a solar panel and capture energy from sun to convert to carbon and eventually soil carbon.
Jamie and Ray have $40.00 per acre in the cover crop mixes. They plant their corn on 36" rows and soybeans with a drill on 7.5" rows. Their drill for cover crops is 12 feet wide. They harvest their crops by day, and plant cover crops by night with a drill. Jamie is planning to aerial seed in August on standing corn. Jamie and Ray understand the principle of keeping plants growing continuously with an active growing root and a shorter interruption in the flow of carbon in the cropping system.
Jamie says that when he was no-tilling without covers, the carbon would burn up by mid-season, and the soils did not have the functioning capability that the covers provide. The soils were harder and had less structure. Infiltration was less. The Weavers are using Haney Soil test and doing plot work. In the plots they reduced nutrients as called by the Haney soil test. On one field (RW3), they followed the University of Tennessee's soil test recommendations of 183-108-92 of nitrogen, phosphorus (P2O5), and potassium (K2O). The corn yielded 178 bushels per acre with a nitrogen efficiency of 0.97. They followed the Haney test on a nearby plot, 110-57-11 of nitrogen, phosphorus (P2O5), and potassium (K2O). The Haney plot produced 173 bushels per acre with substantial reductions in nitrogen (73 pounds), P2O5 (51 pounds), and 81 pounds reduced K2O. The nitrogen efficiency is 1.57. Another field, JW1 followed the standard soil test recommendation of 183-108-92 pounds for nitrogen, phosphorus (P2O5), and potassium (K2O) per acre. In contrast the Haney test plot, they applied 133-85-23 pounds of nitrogen, phosphorus (P2O5), and potassium (K2O) per acre. The corn yielded 178 bushels following standard test results and 168 bushels following Haney soil test results. The nitrogen efficiency is 0.97 for standard test and 1.26 for Haney recommendations. With this information, Jamie will follow in 2016, 140-150 pounds of nitrogen which is about 25 pounds less than standard recommendation. In soybeans, they plan is to reduce phosphorus and potassium in half and apply 20 pounds of P2O5 and 40 pounds of potassium. Cover crops are allowing them to reduce nutrients with equal yields. Jamie said reducing inputs means more profit.
They also are changing from RoundupTM to GramoxoneTM for a quicker termination of cover crops. Their thinking is that the GramoxoneTM will give a quicker kill and allow the corn to get a quicker start. This will cost $4.00 - 5.00 more per acre, but Jamie feels it will easily pay for itself. Jamie plants his crops green. That is he plants in green growing cover crops, and terminates after planting, 1-2 days later. Jamie said you can see the differences in the soil in covers compared to long-term no-till alone. Jamie has done his homework; he is convinced of the benefits of keeping the cover growing as long as possible even when planting corn. He says carbon is the key to improving soil health. Having a green plant growing producing carbon through photosynthesis. He says "we pay $40.00 per acre for cover crops, so we need to receive the benefits." They want to capture as much energy from sunlight as possible and eventually convert it into soil carbon. Ray and Jamie plant corn from second week of April to May 1 depending on weather. The Weavers use row cleaners planting in covers, but with light pressure. Jamie made the point, farmers who use covers need to be patient in planting corn to gain the benefits of covers. Pictured to the left is Ray Weaver standing by planter with NRCS' Area Resource Conservationist, Andy Neal. Corn was planted April 27, 2016.
As we looked over Jamie's fields, April 4, 2016, one could see the changes from the long-term no-till, and the addition of the multi species cover crops. The field (RW3) behind the Church had been in CRP from 1986-1995 and hay from 1995 - 2002. Jamie said that NRCS had done some infiltration tests using the USDA Soil Quality Kit. They measured 6" per hour compared to 2" per hour for nearby no-till only fields. Jamie contributed removing biomass and nutrients in the hay as reasons the field had not performed better. Earthworm casts were visible nearly every time we dug or looked closely at the soil surface. The soils are Baxter and Bodine, cherty limestone soils. The field had five species of cover crops in fall of 2013 and seven species fall of in 2014, and nine species in fall of 2015.
Recently soil microbial biomass was measured in the fall of 2014 and spring of 2015. Any numbers over 6,000 is considered excellent. This field measured over 8,000 in 2014. These measurements show increases in quality as well as quantity in soil organic matter (SOM). The reduced disturbances due to long-term no-till, diverse covers to nine species, and continued root growth from covers and corn-soybean rotation have contributed to these positive numbers in microbial biomass. Other signs of soil health improving is yield based on inputs. The field yielded 185 - 190 bushels per acre of corn with 158 units of nitrogen. Soybeans follow corn in the Weavers rotation. They grow both 3.9 group beans and early group 5s. They drill beans on 7.5" rows. They plant both corn and soybeans in living cover crops and terminate up to two days later. On program fields (EQIP) they use early maturing varieties in order to seed early their cover crops. Non-contract acres, they use group 5 soybeans. Recent soil tests showed ranges of SOM percent from low 2s to mid 3s. These soils in cropland are normally 1-1.5% SOM. Their soils are changing rather quickly.
The local NRCS has also been sampling using Haney Soil Health tests in fall of 2014 and spring of 2016. Samples showed on five different fields considerable changes in respiration rates with ranges 41-50 ppm carbon-CO2 in 2014 with ranges of 140-170 ppm carbon-CO2 in spring of 2016. Respiration rates higher in stable no-tilled fields indicate greater numbers and activity of soil microbes. Soil health calculations are given based on water extractable carbon, nitrogen, respiration rates, and carbon to nitrogen ratio. In 2014, soil health numbers ranged from 6 - 13, and 13 - 28 in 2016. Numbers that are seven or higher show improvement. The numbers of 20 or above show drastic improvements in total organic matter, active carbon, and biological activity. Jamie and Ray's fields are showing great improvements in biological soil health indicators.
Jamie stressed the need to keep cover crops growing in the spring. Early April to the third week of April were ideal growing conditions for the multi species cover crops. Jamie wants to achieve the cover crop's benefits prior to terminating. He says "Farmers a good job of early seeding to assure a stand. We need to do a better job to keep them growing longer to achieve the benefits." Picture on left is power pole chained to drill. They drilled 3.9 group soybeans on April 27, 2016.
Most of Jamie and Ray's fields were planted in covers by early to middle September. One field, the back of their operation, was planted late in mid-October. This was the first year of cover. I could see much less biological activities. The cover was shorter in height. Jamie said currently 100% of their cropland acres are in multi species cover crops. This field will respond quickly to annual cover crops. Jamie says it is a priority of the operation to seed covers. Sometime they have to plant later than ideal, but they want covers on all of the cropland.
According to soil tests, the Weavers' fields are climbing in SOM, active carbon is greater, fungi numbers to bacteria are greater than prior to using cover crops. Soil infiltration rates are increased from 2" to 6" per hour. Yields are similar with 25-50 pounds of less nitrogen per acre. Nitrogen efficiency is better with multi species cover crops. Jamie and Ray are making more profit with less inputs as their soils increase in functioning capacity. Jamie and Ray plan to keep planting multi species cover crops and yielding the results of healthier soils.
Carbon Cycling, the key to High Productive Soils and Higher Profits
Mike Hubbs, TACD Soil Health Specialist
Robert Henley
Coffee County Soil Conservation District is very active in promoting, and are very successful in applying conservation practices to improve soil health. Adam Daugherty, Allen Willmore, the Soil Conservation District Board, and many farmers have come together in unison promoting soil health resulting in over 75 farmers actively practicing long-term no-till and the use of cover crops to regenerate their soils and change the overall soil health. They are mimicking nature with diversity and pumping carbon into the soil to ignite both quantity and quality of soil biology resulting in breaking down freshly produce carbon and improving soil aggregation and nutrient cycling. One farm in particular has been a focus of many soil health meetings, soil health field days, and even the location for NRCS' soil health team to meet and develop our soil health strategy for the state. I know personally that I have been on this farm no less than six times. Robert Henley is agronomist at Security Seed and Chemical and landowner/manager of his farm of 70 acres in Hillsboro, Tennessee in Coffee County. Robert is our 38th Profiles of Soil Health Hero.
Robert is well known in Coffee County in assisting farmers to reach their yield potential in corn and soybeans. Adam Daugherty, NRCS District Conservationist credits Robert and a few other farmers in the county to ask the right questions to motivate thinking and progressing in a carbon-driven agricultural system to transform soils to from somewhat dysfunctional to functional. I first met Robert in February of 2014 at a soil health meeting on his farm. We were touring one of his more productive fields that later in 2014 yielded 315 bushels of corn dryland production in a national corn yield growing contest. Robert, at the time, had some wheat and Austrian winter peas planted for cover crops. We learned from Adam and Robert that the high producing field had been in cattle production for 53 years. It was in predominantly fescue for over 53 years. Unlike many farms that are tilled converting grasses to crop land, Robert no-tilled into the fescue field, so it was never tilled in the last 60 years plus. Robert remarked the day that I interviewed him for this article on October 11, 2017, that the field was left in grass so long because it was thought to be unproductive for corn and soybeans.
Another field that Robert pointed out, on that February of 2014 tour, was a field that was similarly mapped to the high producing field, Hamblen silt loam. This field has had a history of pasturing swine and also was cropped in the 1980s using tillage. Robert told me recently that phosphorus levels are over 400 pounds per acre and potassium are over 600 pounds per acre. So, nutrients are very high. In 1980, Robert reminisced that the field was planted to green beans. They had completed the harvest in wet weather and had severely rutted the field. Robert recalled that they proceeded to work the field up wet. Robert said that the field has not rebounded since that series of events in 1980. On our tour in 2014, the green bean field did not have cover. The following fall, both fields were planted to Austrian winter peas.
The NRCS staff had done significant soil testing and soil health evaluations. Adam Daugherty shared with me that they measured 24" per hour infiltration rate using a 6" single-ring after harvest of corn in 2014. Robert followed with winter cover of Austrian winter peas and during planting of soybeans in 2015, the water infiltration rate was 4" per hour. The question was why. I have seen similar results after a monoculture cover crop of crimson clover in Maury County. Soil biology needs energy to function. Carbon is an energy source. Grass and multi species provide diversity and carbon as energy source. When carbon is not available, soil biology will find it inside and between soil aggregates. The lack of soil structure due to degradation of aggregates in one season showed up in the reduced infiltration rate, but the culprit was platy structure or stratified structure due to soil biology cannibalizing the soil aggregates for energy, thus changing the granular soil structure to platy soil structure.
After the 2015 soybean crop, Robert has been in multi species cover crops consistently. He plants 15 lbs. cereal rye, 10 lbs. winter oats, 15 lbs. triticale, 5 lbs. crimson clover, 4 lbs. hairy vetch, 10 lbs. Austrian winter peas, and 1.5 lbs. of diakon radishes, all species planted per acre basis. His infiltration is back in the 20-24" per hour rate.
The green bean field has lagged behind his high yielding field. In corn yields, it is consistently 30 bushels less. In 2016, which was a very dry late summer and fall, the difference was 92 bushels per acre. In 2014, which was an ideal year for corn, the high producing field averaged 283 bushels per acre compared to 226 in the green bean field. Robert looked at the weather each year and the differences in yield. The good yielding field had 198 bushels per acre in 2012, which was a very poor yield due to over 15 days being over 95 degrees. The county average was 130 bushels per acre. Robert said that he needed to inject carbon into his lower yielding field to give insurance for the dryer years. The NRCS and Robert came up with a strategy to rest the lower yielding field from grain production in 2017. They concocted a cocktail mix of sorghum sudangrass, sunn hemp, soybeans, sunflower, buckwheat, sweet clover, iron clad cow peas, proso millet, pearl millet, daikon radish, phacelia, and purple top turnip. The concept is to pump more carbon into the field in the summer growing months to fire up the soil biology in order to increase the productivity.
The summer cover crop cocktail averaged between 15,000 - 20,000 pounds of biomass. Adam Daugherty injected that where they applied some nitrogen, the summer mix exceeded 30,000 pounds of biomass. Robert Henley said they were trying to emulate the high yielding field that had over 50 years of fescue by producing a large quantity of plant biomass (carbon) in one growing season.
In order to demonstrate the results of soil health practices on soil biology, the NRCS staff buried some cotton made underwear in the high yielding field and also in an adjacent field next door to Robert. That field had been in long-term no-till, left side of picture. but without any cover crops. The results are illustrated by the picture. In 30 days the underwear underneath Robert's high yielding field that had been in cover crops ingested the cotton underwear completely leaving only nylon bands. The no-till field under wear was hardly decomposed almost looking new. The no-till with cover crops literally beat the pants off the no-till only. This suggests that soil biology is picky or have a preference to carbon leaking out of the roots. The no-till field had no decomposition of underwear, but had no structure or platy structure showing the same phenomena as growing only a legume. The soil biology is searching and finding sugar-protein from the soil aggregates. This is fully illustrated also in the lower yielding field that had the massive summer growing mix on it. They also buried underwear under it and found no decomposition of under wear. We know with a terminated winter cover followed by a warm season cover crop mix that soil biology are present. They again showed a preference to sugar-protein leaking from the roots of summer cover crops and did not attempt to break down the less appealing under wear.
Digging and examining soil structure from no-till field and spots without cover showed a similar conclusion. Those areas without cover showed platy structure again crediting soil biology for decomposing glomalin and other important carbon that aggregates soils. The high yielding field with plenty of active carbon from the terminated winter cover mix showed excellent aggregation resulting in excellent yields and water infiltration. The conclusion is we must continuously produce active carbon to improve our soil health. I am convinced that a field without a growing plant is a degrading field.
As I mentioned previously, Robert is proficient at reaching high yields in corn and soybeans, and he advises others to reach high yields. Robert is tweaking the cover crop system to be more productive. He mentioned that his current system is resilient regardless of the season. Robert mentioned assisting farmers with irrigation on their farms only showed increased yields only 20% of the time, one year out of five. He said the reason was poor water infiltration which he measured at 0.1" per hour. The problem was not the lack of water but the soil being dysfunctional and could only infiltrate 0.1". Farmers need to treat the problem which is an infiltration problem not the symptom with adding more water. Robert concluded it is much more profitable to pay up to $50.00 per acre for cover crops than to invest in irrigation system.
Robert and Adam both mentioned that farmers considering using cover crops are too concerned with temperatures at planting. This last spring was wet and cool. They took temperatures in no-till, conventional tillage and cover crops and found 3 degrees differently. However, they have done earlier temperature studies in June and July and found cover crops to be 8-10 degrees cooler than ambient temperatures and conventional tillage and no-till to be as much as 13 -15 degrees warmer than ambient temperatures. Robert and Adam both said they are looking at not planting corn until soil reaches 65 degrees because the cover will provide the benefits needed to achieve higher yields even though the planting date may be somewhat later. They both said that the system with cover crops are so much different from a traditional no-till system that is different from the old traditional conventional tillage system.
Robert had advice to farmers not willing to plant cover crops. He has noticed that corn does better and show better soil aggregation when planted to 2" in depth. He compared a farmer's field that was planted at 2" depth to areas planted at 1 3/4" depth. The corn planted at 2" depth yielded 300 bushels per acre irrigated where the corn planted 1 3/4" depth yielded 280 bushels irrigated. Areas showed differences in aggregation too. Robert is also a believer of sulfur. He thinks it is economic to apply much higher rates of sulfur, as much as 100- 150 lbs. per acre. He also noted that where he sees highest yields in corn the soil copper is high. He is an advocate of placement and timing of nutrient placement. He soil tests by zone and focuses on placement and timing instead of mass balance. He gave example that old school nitrogen (N) fertilization was 1.5 lbs. per bushel of corn production. Robert said with multi applications and timing, he could reduce it to approximately 0.4 lb. N per bushel of corn. He applies N three times on high yielding areas and two applications on rest of farm. He also quit applying side dress N between rows, 15" from corn. He now applies liquid N (32% solution) on both sides of corn at a reduced rate (half what the 15" amount is). He sees less decomposition of cover and the corn is yielding better. Previously at 15" centers the N application looked like a blow torch had been applied to the residue.
Coffee County has been soil testing with Haney test and Phospholipid and Fatty acid (PLFA) sampling for three years. These results are showing high amounts of soil biology over 12,000 ng/g at planting compared to another cover crop farmer at 2,500 ng/g. Robert's field is turning over or consuming high amounts of active carbon. The soil organic matter is 2.5 -3% but the soil health changes are due to the soil aggregation and nutrient cycling resulting from high populations of soil biology and large amounts of active plant biomass being consumed. We do not need to be concerned with levels of soil organic matter. Robert also noted that his cation exchange capacity was 19 melliequivalents per 100 grams of soil which is high. The constant production of carbon is making a difference in his soils.
On his pest management program, Robert has not made any change as of yet, but is seeing less pigweeds and mares tail due to the cover crops. He said he currently uses two sprayings for pigweeds/mares tail where traditionally, farmers would use 3-4 sprayings. He thinks by the 4th to 5th year using cover crops, he could knock out a second spraying of post applied herbicides by using rolling and crimping on cover crops.
Robert compared his average $30.00 per acre investment of cover crops to some nearby farmers paying $50.00 per acre for chicken litter. Robert said the scary part was there was no analysis on the litter. Farmers need to know what they are applying per acre. Robert says every farmer needs to invest in a shovel and examine their fields. Functioning soils are much more profitable than non-functioning soils. Robert believes in rolling and crimping his cover crops except when planting crops with a drill. The drill knocks the cover down at planting in an orderly fashion; if the biomass is at a conducive stage for crimping.
Robert said that farmers growing crops near tree lines could be more efficient by planting grass buffers adjacent to tree lines. Robert has noted 100-bushel difference between corn in the middle of field compared to near tree lines. He said farmers are wasting resources by planting crops near tree lines. Robert is not afraid to get out of the box and break tradition in order to change his soils and his bottom line. Many farmers have and are learning from what Robert is doing on his farm. The take home message is to mimic nature by keeping a plant growing 365/24/7 to increase carbon production (photosynthesis), protect the benefits by no-tilling, and diversify too increase quantity and quality of soil biology to cycle the carbon to improve soil function and improve farm profit.
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