Bulletin #1075, Tarping in the Northeast: Conclusions
Tarping encompasses several valuable management techniques for different cropping niches on small farms. These techniques complement—but are not substitutes for—other soil health-building and weed management tactics. Increasingly important, tarping can help farmers adapt to climate change by regulating moisture dynamics and facilitating reduced tillage with or without high levels of residue. While the use of plastic in agriculture has drawbacks, tarping can provide some environmental benefits; specifically, retaining mobile nutrients like nitrate reduces nutrient pollution and reduces the need for fertilizer, and overwintering tarps can protect vulnerable soil from erosion when it is impossible to seed a cover crop.
Many questions remain regarding how different tarping practices and materials affect weeds, soil organisms, nutrient cycling, and labor and economics on the farm. Further work could refine best management practices that minimize the opportunity cost of tarping, while achieving specific weed, soil, or cropping system goals during our relatively short growing season in the Northeast. Additional research could further illuminate temperature, time, and light thresholds for seed mortality, fatal germination, and bud mortality of individual weed species, as well as the effects of tarp permeability (i.e. different tarp types), edge securement, and organic amendments on soil biological activity (including pathogens), gas exchange (i.e. oxygen levels), and nutrient cycling. Despite many remaining questions, there is ample evidence—both from farmer experience and research trials—that tarping holds promise for multiple applications on small farms in the Northeast.