Blackberry Farm
A Day with Blackberry Farm, Producing Organic Heirloom Vegetables Without Tilling
Blackberry Farm is a 4,200-acre luxury hotel resort located in Walland, Tennessee, near the Great Smoky Mountains National Park. Blackberry Farm was
built in 1939 and has evolved into the luxury resort in Blount County that it is today. My interest in Blackberry Farm began about a year ago in September, 2016. I was asked by Blount County Soil Conservation District's Conservation Director, Erich Henry to join him to work with Michael Washburn, Garden Manager at Blackberry Farm. In 2015, Michael became the garden manager. The garden consists of approximately 3 acres. The garden produces heirloom vegetables that are served at the resort's two kitchens. There is close correlation and team chemistry between the gardeners and the chefs.
I could tell when I first met Michael Washburn that he was a trained agronomist. He also had experience in restaurants, so again you could see a close correlation of producing and preparing the food. The garden produces food organically. They are not organic certified, but they grow food without chemicals and work on improving their most important natural resource, their soil. Some areas and especially one of the lower fields that had been regularly tilled in the past, were of particular interest. Here soil structure was still lacking. Michael had already followed some great conservation practices. They were making their own compost and applying it regularly. Michael had done research on biochar and constructed an outdoor stove to burn wood and collect the char. You can see the black char in the rows of vegetables. Compost is an active carbon source that feed soil biology. Biochar is a stable carbon source. Many of the chemical properties of soil from humus can be improved by adding bio-char. For background, go to Terra preta on Wikipedia, Terra preta is Portuguese for black soils. Michael is emulating Terra preta by adding bio-char.
opportunity to previously visit the farm in October of 2015. The two previous years of cover consisted of rye and crimson clover. This year was a five-way mix aerial seeded in early October. The stand was decent despite the drought, last Fall. Also, joining me on the visit were two farmers from Haywood County, a farmer from Lauderdale County, a Farmers Cooperative employee working Tipton and Lauderdale Counties, and NRCS employees from Brownsville, Tennessee, Joshua Choate, District Conservationist, and Melissa Rodriguez, Soil Conservationist. First of all, it was amazing the surface changes in the soil noted while digging. The soil was much fluffier or had better tilth. The structure had changed from a platy structure to much more granular and sub-angular structure. We like to see soil structure with the somewhat rounded shapes similar to marbles in a glass. They form soil-voids or pore space that leads to porosity. Porosity provides space for air and water movement most notably improved infiltration rates. We have noted anecdotal evidences for years with cover crops and no-till. We see it when comparing samples with the rainfall simulator. When compared to long-term no-till and vertical tillage and conventional tillage, samples with two to three years of history of cover crops and no-till perform better under rainfall simulator. They infiltrate better due to more cover and better aggregation due to more active soil biology. There is less run-off and erosion. Water is more efficiently infiltrated and utilized by plant roots. We also observed many earth worms in every shovel full of soil. Bill remarked that he had not seen many earthworms in the past. Earthworms is a macro biology indicator that soil health is improving. Earthworms, like other soil organisms, feed off other soil biology such as bacteria, fungi, nematodes, etc. as well as soil organic material from crop residues and cover crops. Lack of tillage is very favorable to earthworms. As time persists with no-till and cover crops, earthworms and other soil biology will increase. These organisms increase nutrient cycling, aggregation of soil, and movement of nutrients and soil organic matter both upward and downward. Earthworms are nature's tillers. Another indicator that was very observable was the strong earthy smell when digging. The sweet soil aroma was much less in 2015 compared to now. Earthy smell is from geosmin, an organic compound produced from actinomycetes, a colony growing bacteria. As soil is undisturbed and organic matter increases, soil earthy smell increases.
current Acting State Conservationist, Jamie Carpenter is following Kevin's lead and promoting soil health. It helps that Jamie's normal job is Assistant State Conservationist for Programs. Having Programs focusing on soil health is huge for promoting and providing financial assistance. Tennessee Department of Agriculture is another major partner that is also supporting soil health in working with District Supervisors and financial support. Again, the team approach has been instrumental to Coffee County's support as well as the entire state of Tennessee.
Coffee County, like Tennessee, has embraced soil health in 2013. Adam Daugherty, NRCS District Conservationist, Coffee County convinced the Soil Conservation Board that this was the direction they needed to go. Coffee County was already a leader in no-till. They were doing a good job in natural resource conservation. The systems approach of mimicking nature, a deciduous forest was the missing piece. Bringing in cover crops were important, but understanding the function of soils and mimicking a forest was the key. The Soil Conservation Board not only supported the aggressive approach but many of them also jumped in and applied many soil health improving practices.
Traditionally, farmers have grown cover crops to around knee-high and waist high, killed the cover approximately two weeks before planting of corn or soybeans and plant in a crispy or dead cover. The weaknesses of this system are it limits the growth in the spring especially in corn. Some farmers in counties as south as Coffee County begin thinking about planting corn in March. As we know, cover crops are fairly short in March and just beginning to kick in another gear in the end of March, especially species such as Austrian winter pea, hairy vetch, and crimson clover. In fact, we dug these plants up on April 25 and found many nodules on the roots of each species of legumes. Nodules when they are pink indicate they are producing nitrogen. To kill legumes early, would be to lose a major benefit from the legumes in the mix. Farmers in Coffee County have learned to wait to plant corn to middle to third week of April. I know there are exceptions, but many farms that we visited had planted only about 7 to 10 days earlier. It was very wet on the April 25th, about 8 inches of rain had fallen a few days prior to our visit. Corn was germinating why we were there with a few acres of corn was still to be planted. Another weakness of planting crispy is once you terminate the cover, there is not an active root growing. This year we are bombarded by rain and cool weather. Having a root growing right up to planting is great way to drain uptake the excess moisture. Once the cover is terminated, the residue will hold the moisture in to the soil. Warm weather will eventually alleviate this problem.
the termination.
Since Coffee County has farmers in the fourth season of cover crops, it was great to see the benefits after four years. Some of the observations were on a steep red-clay field that had been in covers for approximately three years. They had been killing the covers early about knee-high to preserve the moisture going into summer. Now after some of accumulation of soil carbon, they were letting the cover grow higher. The field was functioning at a higher-level due to the three years of no-till and cover crops.
Soil structure in all the fields we looked at are granular at surface with some sub-angular soil structure as we dig deeper into the soil. This is why Coffee County is seeing 6-8" or greater per hour of water infiltration. We have seen by comparing some bare spots or some monoculture-legumes as cover crops that we can lose this soil aggregation quickly and water infiltration will go back to 2-4" per hour. We need diversity and cover continuously to keep soils aggregating. Active carbon that is recently dead residues and cover crops are the key to aggregating soils and for nutrient cycling. Total carbon or soil organic matter is important to keep climbing, but it is much more important to see diverse high-quality carbon being produced annually and being consumed by soil biology providing policing of soil disease, cycling of nutrients, and aggregating soil. If we continue to keep the soil covered, keep an active root growing, reduce disturbances, and maintain diverse covers we will continue to see our soil health or functions improving.