Bulletin #1075, Tarping in the Northeast: A Guide for Small Farms

Tarps covering garden beds — Tarps covering beds and integrated into the field planning at Centurion Farm. Photo: Nina Saeli.

Bulletin #1075, Tarping in the Northeast: A Guide for Small Farms (PDF)

Authors:

Natalie Lounsbury, Postdoctoral Research Associate, University of New Hampshire Department of Natural Resources and the Environment
Sonja Birthisel, Faculty Associate, University of Maine School of Forest Resources and Ecology and Environmental Sciences Program
Jason Lilley, Sustainable Agriculture Professional, University of Maine Cooperative Extension
Ryan Maher, Research and Extension Specialist, Cornell Small Farms Program, Cornell University

The authors would like to thank Maeve Wivell, Molly Shea, and Sue Ishaq, for their research and writing contributions to this guide as well as the farmers who graciously shared information about their operations for the Case Studies, including Dave McDaniel and Heather Selin, Molly Comstock, Ben Stein, and Alicia Brown, Ryan and Kara Fitzbeauchamp, Daniel Mays, and John Hayden. Additionally, we would like to thank Becky Maden, Anu Rangarajan, Peyton Ginakes, and Johnny Sanchez for helpful reviews.

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Introduction

Reusable tarps, including black plastic (silage tarps), clear plastic, and landscape fabric, are multi-functional, accessible tools that are increasingly popular on small farms. The use of opaque materials that block light is frequently called “occultation” while the use of clear tarps is called “solarization.” We treat “tarping” as a general term to include both. Regardless of the material used, tarps are applied to the soil surface between crops and then removed prior to planting.

Definitions
Solarization is the practice of using clear tarps to capture solar energy and heat the soil surface. The effects of solarization on pests (weeds and pathogens) and beneficial organisms are highly dependent on weather conditions.
Occultation is the practice of using opaque (typically black) tarps to block light and therefore prevent photosynthesis. The word has Latin origins, meaning “to block.” The effects of occultation are less dependent on, but nonetheless affected by, weather conditions.

In cool climates like that of the Northeastern US, tarping has emerged as an important way to manage weeds, crop residue, soil moisture, and nutrients. Tarps can be versatile tools left in place for days to months at a time depending on context. They are commonly seen as ‘placeholders,’ covering soils to keep them weed-free and to retain moisture and nutrients until planting time. Many farmers use tarps to reduce the intensity of tillage or the number of tillage passes, while other farmers have moved to rotational no-till or even continuous no-till with tarps. Tarps have also been deployed as a way to transition new fields into production.

Farms using tarps are generally small (<5 acres) and employ organic practices, however, the reasons farmers use tarps are diverse. A recent survey of farmers in the Northeast (Rangarajan 2019) showed that there are many different goals with tarping.

Graph showing percent of farmer survey participants who ranked various goals of tarping as moderately or very important on their farm: Kill cover crops = ~35%; Increase soil nutrient availability = 40%; Kill sod = ~50%; Warm soils = ~52%; Protect soil overwinter when not cover cropped = ~56%; Decompose residue = ~58%; Kill emerged weeds before planting = ~65%; Kill weeds after crop harvest = ~66%; Create a stale seed bed = ~75%; Hold fields weed-free until planting = ~82%; Allow early spring access = ~85%; RT and to improve soils = ~88% — Percent of farmer survey participants who ranked various goals of tarping as moderately or very important on their farm. (Rangarajan 2019)

Despite the advantages of using tarps, there are tradeoffs to this practice and many unknowns. Farmers cite the logistics associated with handling tarps, including moving, securing, and storing them, as especially challenging. Because of these challenges, tarping is currently scale-limited. Tarping is a powerful weed management tool, but some weed species can become problematic when tarping is deployed without additional or alternative weed management techniques. Occupying valuable field space during the growing season with a tarp on land that would otherwise be planted to cash or cover crops represents an opportunity cost, and the benefits of tarping must outweigh the time required to implement the practice effectively. While tarps are reusable, they are made of plastic; manufacturing, disposal, and plastic contamination during their use are concerns.

This guide is intended for those who are interested in or currently using tarps and would like to know more. The individual practice sections and farmer case studies serve as standalone resources. Research results and farmer experiences from multiple states in the Northeast have been combined to provide a thorough and up-to-date picture on the state of tarping knowledge including logistics, science, and economics.

Types of tarps and how they work

General logistics of tarp management

Tarping Practices

Concerns with Plastic Use

Conclusions

Farm Case Studies

Works Cited

Acknowledgments

This publication was funded in part by the Northeast IPM Center through Grant #2018-70006-28882 from the National Institute of Food and Agriculture (NIFA), Crop Protection and Pest Management, Regional Coordination Program. Additional funding was provided through Northeast SARE Project LNE18-371, Northeast SARE project LNE19-382, USDA NIFA OREI 2014-51300-22244, USDA NIFA Agriculture and Food Research Initiative (Niles, 2018-68006-28098), USDA NIFA Hatch Projects 100682, 1004501 and 1013971, and the New Hampshire Agricultural Experiment Station.

logos for: The University of Maine Cooperative Extension; University of New Hampshire NH Agricultural Eperiment Station; Cornell CALS; Cornell Small Farms Program; Northeastern IPM Center; USDA NIFA; Northeast SARE: Sustainable Agriculture Research & Education

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

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