- CHRISTINE MANUCK
Evaluating Reduced and No-Till:
Findings from a Three-Year Study of Northeast Farmers Utilizing Alternative Tillage Systems
BY CHRISTINE MANUCK
In 2019, the NOFA chapters, led by NOFA/Mass, were awarded a U.S. Department of Agriculture-funded project, Organic No-till on Northeast Farms: A Practical Exploration of Successful Methods. The project funded a multiyear evaluation of soil carbon, pests, and yield for 9 farmers committed to performing reduced or no-till farming. Farmers were encouraged to trial different management strategies to help guide their transition as they reduced tillage. In addition to regular learning cohort discussions, farmers also participated in soil health field days throughout the three-year project duration to encourage peer-to-peer learning. Data from soil carbon proxy testing, pest, and yield measurements found some modest improvements in soil bulk density, soil aggregation, and soil hardness. Farmers also reported a benefit from participating in the learning cohort calls and no-till methods trialing. Outreach successfully helped over 3,000 individuals learn more about soil carbon and soil carbon proxy testing, the benefits of reduced and no-till agriculture, and the practical implementation of different management strategies.
Transitioning Agriculture from a Carbon Emitter to a Carbon Sink through Tillage Management
Soil has the capacity to absorb a significant quantity of carbon, but it can only serve that purpose if, on the individual farm level, farmers understand and implement the best practices to capture carbon and monitor changes over time. Despite currently being a high emitter of climate change-inducing CO2, agriculture is the one industry that has the capacity to absorb more CO2 than it produces, with the potential to sequester between 25 and 60 tons of carbon per acre. Absorptions on this level would offset over 35% of global anthropogenic greenhouse gas emissions. By focusing on improving soil quality and putting carbon back into the soil, farming for carbon sequestration can benefit both crops and the environment. When soil is exposed to the air, such as through tilling, carbon molecules in the soil are released into the atmosphere. Tillage reduction is a key way to keep carbon in the soil, helping agriculture to transition from a carbon source to a carbon sink.
Interest in tillage reduction practices has been increasing in popularity over the past two decades. No-till management can protect soil, conserving its properties and nutrients, while offering a potential means to save time and money. By minimizing soil disturbances, no-till farming can benefit soil water retention, nutrient storage, microbial and fungal life, and ecosystem diversity, which all directly impact crop growth. Conventional no-till farming frequently relies heavily on synthetic herbicides for weed control which are unavailable to organic farmers, requiring organic and herbicide-avoiding farmers to utilize other management strategies to make it successful for them. Such farmers are finding ways to transition to no-till production while avoiding herbicide use through methods including permanent bed systems, cover cropping, solarization and occultation, and use of no-till equipment such as the flail mower, chisel plow, tandem disk, and broadfork.
Through the USDA-funded Conservation Innovation Grant (CIG) project, NOFA chapters in Massachusetts, New Jersey, and Connecticut developed a learning community of farmers in the Northeast who have been integrating reduced and no-till methods on their farms. The goal of the project was to increase the practice of organic no-till farming among Northeast farmers by supporting existing low and no-till growers as they innovated and experimented with proven and new methods. To achieve these goals, the three participating NOFA chapters spent the past three years evaluating changes in soil carbon at 9 partner farms in New Jersey, Connecticut, and Massachusetts. Farmers participated in regular calls to develop a learning community around organic reduced/no-till production and to foster and support innovation between farms and also participated in community-wide educational events and workshops to share techniques. The farms partnered with their state extension agents to collect data on various indicators to evaluate the role of reduced and no-till in controlling and maintaining crop pests.
Farms participating in the project were, in Massachusetts, Freedom Food Farm, Gaining Ground Farm, and Red Shirt Farm; in Connecticut, Assawaga Farm, Massaro Farm, and Subedge Farm; and in New Jersey, Ironbound Farm, Morganics Family Farm, and Northslope Farm. Farms were selected based on their tillage practices at the project's outset and committed interest in reducing tillage over the duration of the project. In addition to participating in learning group calls, farmers also provided records of crop yield, weed pressure, and pest observations over the project duration. NOFA/Mass staff performed soil carbon proxy tests at each farm annually to evaluate any changes in soil carbon sequestration and soil organic matter.
Soil carbon proxy testing offers an indirect, field-based measurement of soil carbon and soil organic matter. As the main component of soil organic matter and responsible for a soil’s water-holding capacity, structure, and fertility, soil carbon plays an important role both in agriculture and the environment. Soil carbon proxy testing uses indicators commonly associated with the presence of carbon to indirectly evaluate the amount of carbon in soils. Certain physical, chemical, and biological components of soil, such as soil aggregates and water infiltration rate (physical), active carbon (chemical), and earthworm and root counts (biological), are highly present in soils abundant in carbon and, consequently, in organic matter. By assessing for these components, soil carbon proxy testing offers a way to quantitatively and qualitatively measure a soil’s organic carbon content, and thus soil organic matter content, through a series of field-based metrics. In the context of the CIG project, soil carbon proxy testing was the primary means of assessing changes in soil carbon sequestration in response to changes in tillage management and practice implementation. Soil carbon proxy testing was supplemented with farmer surveying of management practices, crop yields, and pest pressures to understand the tillage practices and their effects on crop production and pests.
Project findings showed improvements in some soil carbon proxy test metrics, including soil hardness, bulk density, and depth to compaction, particularly when data was divided between farms performing reduced tillage and those performing no-till. Soil hardness was consistently lower for no-till farms than for reduced-till farms, as was depth to compaction. However, bulk density increased for no-till farms but decreased for reduced-till farms. Aside from soil hardness, bulk density, and depth to compaction, overall findings revealed mixed results on the effects of reduced and no-till management on other soil carbon metrics, crop yield, and pest pressures.
Self-reporting from project farmers on yield, pest, and crop damage resulted in only one farm reporting an improvement in crop yield, for spinach, compared with previous years. Crop yield findings reported by other respondents throughout the study found mixed results, with yields increasing for some crops in some years and decreasing for others. Similarly, farmers did not report either major improvements or negative impacts from no-till on pests; pest interventions and estimated production costs were found to be roughly the same as prior to starting no-till. Of the possible benefits observed by some farms, cabbage worms and potato beetles were the two pests identified as potentially decreasing in prevalence over the duration of the three-year project.
Weeds presented a significant issue for one participating farm that produces oats. While mowing instead of tilling reduced the amount of thistle in their fields, pressure from other weeds that were uncontrolled by mowing intensified. The farmers mowed early in an attempt to help oats get ahead of other weeds but were unsuccessful, leading to a nearly complete crop loss and the farm’s worst production year ever. They ultimately concluded that, while zero tillage has benefitted their soil health, they would still need light, superficial tillage before spring oat crops. Minimal tilling for weed control was echoed by some other farmers, highlighting one of the primary issues facing farmers considering transitioning to no-till.
No-till management trialing was successful for farmers, as they were given the freedom and support to try different methods than they may have without the support of the project learning cohort and advisors. Management strategies trialed included solarization, occultation, interseeding, and mulches for weed control, cover cropping, board crimping, and use of a seed drill. In some instances, the strategies were successful, such as the use of tarps allowing farmers to dramatically reduce rototiller use, whereas others were less successful, such as when legume cover crops were consumed by deer. In response to findings such as these, NOFA/Mass staff developed a No-Till Methods Fact Sheet of the different management strategies trialed by farmers throughout the project and the findings from each experience.
Both reduced and no-till farming have proven benefits to soil carbon, pest pressure, and yield. As no major changes to these components, whether positive or negative, were observed over the duration of the project, it is very possible that the three-year project duration was insufficient to capture the effect of these management changes over time. The general expectation is that it can take several years for pest pressures to begin to reduce after transitioning to a no-till system, and it is likely that the duration of this project failed to capture these potential improvements.
All NOFA chapters participating in this project led several on-farm events, workshops, and other educational outreach efforts to help promote reduced and no-till farming. Education outreach ranged from the practical implementation of no-till farming to soil carbon proxy testing demonstrations to field-based demonstrations of different equipment used by no-till farmers. In addition to the quarterly farmer cohort learning calls, NOFA/Mass also implemented a monthly minimum-till call available to farmers and gardeners on a “drop-in” basis on the first Monday of every month. Stemming from community interest in reduced and no-till methods, the ongoing calls have become an opportunity for the community to learn more about different management strategies from other farmers and gardeners. The calls’ informal nature makes them inherently welcoming for all individuals regardless of background and experience, ultimately increasing the potential for peer-to-peer learning by individuals all aspiring to shared goals.
To further study the effects of reduced and no-till management changes on Northeast farms, this project should be repeated in a more controlled format evaluating management and results of soil carbon, pest, and yield. Completing the project of a longer duration, such as 5-7 years, could also capture soil’s progression and changes in response to reductions in tillage, and its downstream effects on pests and yield. A longer project would also create a greater opportunity for farmers to evaluate different no-till methods and to see any effect from them on soil carbon, pests, and yield metrics. In addition, involving a larger cohort of farmer participants would provide greater statistical power to support findings and a better learning opportunity for farmers in discussing no-till approaches, successes, and failures.
Soil carbon proxy testing and soil health assessments are a primary component of the soil technical services offered to farmers and gardeners by NOFA/Mass and other NOFA chapters in their states; contact your state NOFA chapter for more information. For more information on the NOFA CIG project described here, including information on the farmers, No-Till Methods Fact Sheet, links to recorded education events, and a full report of project findings, please visit the NOFA/Mass CIG website at https://bit.ly/NOFA-CIG.