Adding Nine Species of Cover Crop Mixture to Improve Soil Health
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.