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Betts Farms, owned by Bob, Dawn, and Thom Betts, has been on the forefront of vineyard middle-row soil management for the past decade, continuously improving soil health on their 185 acres of Concord vines. In contrast to standard Concord viticulture practice, where middle-row grass and weeds are burned in late spring to ensure optimum vine fertility, growers like the Betts are establishing cover crops to alleviate soil compaction, reduce erosion, build soil organic matter, and foster life in the soil. Bob Betts initially planted cover crops to correct the negative effects of soil compaction on water infiltration, root proliferation, and vine productivity, but he soon saw additional benefits in soil structure and the biological health. After 11 years experimenting on a 5-acre vineyard block, Betts saw results that convinced him to incorporate cover crops on all 185 acres.

It started as an experiment… 

In 2011, Betts planted several middle-row alleys with winter tillage radish in an effort to alleviate soil compaction. Radishes are brassicas that form a thick taproot, like a carrot, and are known to break up soil and scavenge excess nitrate. When the radish dies, the large taproot decays to create soil pores that encourage water infiltration and gas exchange. Betts strategically planted in rows with new tile drainage to see if soil pores would channel water to the tile lines below.  The water infiltration improvement was evident, along with an unexpected benefit in the form of high biomass production, or the amount of living material generated from planting the cover crop (Figure 1). The Betts noticed more earthworm activity, soil stability, and a decrease in weed pest pressure in the middle rows where they planted the winter tillage radish. 

Figure 1: Bob Betts proudly shows a well aggregated clod from a cover cropped area (left) and a compacted clod from a non-cover cropped area (right).

The success prompted Betts to expand his cover crop repertoire in 2012 by seeding alternating bands of annual ryegrass and radish seven inches apart, for a total of nine bands per middle-row. The ryegrass was intended to complement the large holes left by decayed radishes. which allowed for the water infiltration that they were hoping for, but also created unstable ground for tractor access. Adding the ryegrass species, that has an extensive, soil-holding root system, helps to stabilize the ground during wet periods to allow for easier tractor access. The experiment wasn’t entirely successful, as the radishes crowded out the ryegrass, a common occurrence if radish seeding rate is too high (one extra pound of radish seed per acre can make a huge difference) or there is high residual nitrogen in the soil. 

Fortunately, financial help arrived in the form of the  Environmental Quality Incentive Program (EQIP), a National Resource Conservation Service (NRCS) subsidy funding cover crop efforts to combat erosion and improve soil health. Betts took advantage of their prescribed mixes of three to seven different seed species, and worked with the Lake Erie Regional Grape Program (LERGP) to alternate mixed planting with fallow plots three panels long by three rows wide (24 X 9ft) to serve as an experimental control. This experiment block has been ongoing for eleven years.  

The Betts Farms cover crop program has helped address many practical concerns, including erosion, summer moisture retention, and weed suppression. Betts has further innovated by initiating use of a 5-foot-wide I & J roller crimper in 2015 to terminate cover crops in June, an uncommon practice in Concord grape vineyards. Rolling the aboveground portion of the cover crop protects the soil from rain droplet impact, while cover crop roots hold soil in place during periods of intense rainfall (Figure 2). This decreases the runoff and erosion that may carry pesticides, valuable nutrients, and topsoil away from the grapevines. The roller treatment also addresses the concern that cover crops might compete with vines for soil moisture during times of drought, as the biomass mat created in early June shades the ground, retaining soil moisture. The mat also results in cooler surface temperatures, creating better soil microbe habitat than hot, dry, bare soil. 

Both the actively growing cover crop and the biomass mat help suppress weeds, which is especially important for problematic annual species like Marestail (Condyza canadensis), a plant commonly resistant to glyphosate (Roundup). While Marestail was a significant problem in Betts Farms’ control rows, it was rare in cover cropped rows that had been rolled and crimped (Figure 2), which reduced his overall reliance on glyphosate. The biomass mat provided adequate weed prevention most years, and if it doesn’t, herbicide can be applied as needed.  

Figure 2: A mat of rolled cover crop biomass protects soil during an intense rainfall event that delivered 5 inches in 2 hours on July 14th 2015 (left), cover crops reduce weed growth, as evident here: Marestail (Condyza canadensis) grows in control area, but not in the cover cropped portion behind it (right).

Soil Health Benefits

In addition to the ‘above ground’ benefits, visual inspection makes it obvious that life below ground has improved, too. Earthworms, nature’s plows, are increasingly prevalent. As earthworms eat, soil and decomposing organic matter are mixed together in their gut, then deposited as ‘casts’—stable assemblages of organic and mineral particles atop their burrows. These casts are more fertile than the surrounding soil and help increase nutrient availability for the shallow-rooted grapevines. Betts has also noticed increased lateral vine root growth in areas of increased earthworm activity.

To confirm the empirical observation of improved soil health, Betts worked with Cornell’s New York Soil Health Initiative in May 2021 to collect four composite soil samples from the cover crop and non-cover crop control treatments for a standard soil health assessment at the Cornell Soil Health Lab. Six, 0-6”soil slices were taken as composite samples from two locations within the experimental area, classified as a Barcelona silt loam, which is comprised of approximately 13% sand, 60% silt, and 27% clay. 

The soil samples from the cover-cropped plots had consistently higher soil respiration (27%) and aggregate stability (58%) compared to the non-cover cropped plots (Table 1, Figure 2). Higher soil respiration indicates that cover crop biomass inputs are fueling soil microbe conversion of organic residues into mineral-accessible nutrients, such as nitrate and ammonium, faster than in the controlled plots. Higher aggregate stability measurements confirmed that the soil under cover crops was much better aggregated compared to the non-cover cropped, more compacted, soil (Table 1, Figure 3). Living roots, their associated mycorrhizal fungi (AMF), and increased organic matter all help build and maintain stable aggregates, which in turn support greater water infiltration and reduced topsoil erosion. This is evident in a comparison of respiration and aggregate stability values and soil health scores for the Betts Farms treatments compared to pastures and perennial fruit (orchards and vineyards) on silt loam soils in New York (Figure 3). No significant differences were observed in soil organic matter and active carbon, which may be due to high initial levels of soil organic matter and inherent site variability. There is an indication that cover crops make phosphorous (P) and potassium (K) more available, which could help increase vine productivity. 

Table 1: Cover crop (CC) vs. non-cover crop control (NCC) treatment effect for the Betts Farms vineyard in 2021. These values reflect the mean of two composite soil samples per treatment. The abbreviations in the table are as follows: Treatment (Trt), Soil Organic Matter (SOM), Respiration (Resp), Aggregate Stability (Agg Stab), Phosphorus (P), Potassium (K), Magnesium (Mg), Iron (Fe), Soil Health score (SH score), Cover Crop Treatment (CC), Non-Cover Crop Treatment (NCC).

Figure 3: Soil health benchmarking of Betts Farms soil respiration (a) and aggregate stability (b) compared to other pastures and perennial fruit systems on silt loam soils in NYS. 

Vine Productivity Benefits

The ultimate test of any management system is its effect on productivity, and farmers dream of finding a win-win solution that both improves soil health and increases crop yield. Through pruning weight measurements taken between 2019-2021, vines in cover cropped plots where shown to have consistently higher pruning weights than control plots (Table 2). Pruning weights measure the annual growth removed from dormant vines as an indicator of larger vine size and potential crop yield, so higher pruning weights demonstrate that cover crops have improved soil health and nutrient availability, in turn supporting better vine growth. Conversely, loss in vine size would have indicated that cover crops competed with vines for water and nutrients. To verify this effect, crop yield data will be analyzed over the coming years to assess pruning weight trends.  

Table 2: Pruning weights for cover cropped and non-cover cropped areas between 2019-2021.

Conclusion

Bob Betts began his farm’s cover cropping trial in an attempt to reduce soil compaction, but found that it also led to improved soil health and vine productivity. This case study was instrumental in securing additional funding for Betts Farms, working with the Cornell Lake Erie Research and Extension Laboratory, NRCS, New York Soil Health Initiative at Cornell, and the New York Farm Viability Institute, to explore further research efforts designed to improve vineyard soil health and achieve farm goals. Stay tuned for more exciting vineyard cover crop innovations!

Jennifer Phillips Russo is an extension associate and viticulture specialist for Cornell Cooperative Extension. She is part of the Cornell Lake Erie Research Extension Laboratory (CLEREL) and serves as team leader for the Lake Erie Regional Grape Program. Bob Betts is the fourth-generation farmer and owner of Betts Farm in Westfield, NY. He is passionate about multi-species cover cropping research. Joseph Amsili is an extension associate and program coordinator with the Cornell Soil Health Program and New York Soil Health Initiative.