Amending pasture soil to decrease weed presence while improving forage species composition and quality

Project Overview

Project Type: Farmer
Funds awarded in 2011: $10,706.00
Projected End Date: 12/31/2012
Region: Northeast
State: Maine
Project Leader:
Bill Errickson
Singing Nettle Farm

Annual Reports


  • Agronomic: general hay and forage crops, grass (misc. perennial), hay


  • Animal Production: inoculants, mineral supplements, pasture fertility, pasture renovation, range improvement, feed/forage
  • Crop Production: biological inoculants, no-till, organic fertilizers, tissue analysis
  • Pest Management: weed ecology
  • Production Systems: organic agriculture
  • Soil Management: soil analysis, soil chemistry, soil quality/health

    Proposal summary:

    On many farms in the Northeast, pastures tend to decrease in appropriate forage species for grass-fed animals while increasing in weed species over time, likely in response to decreasing soil fertility. When soil nutrition is compromised, the vigor and stand density of desirable forage species decline, allowing weed species to establish as hay quality diminishes. Because animals tend to graze species they find palatable while avoiding weed species, farmers with weed-dominated pastures need to increase the amount of hay fed to pastured animals, thus increasing their operational costs. Additionally, in weed-dominated fields with low soil fertility levels, nutrition available to the animals may be compromised, necessitating the feeding of often-expensive supplements to maintain optimum animal health. Many recommendations for pasture renovation suggest mechanical cultivation, chemical weed suppression, and reseeding. While these methods may produce the desired results, they also have ramifications of increased soil erosion and compaction, environmental degradation, and cost, while failing to address the underlying nutritional deficiencies that are promoting weed growth in the field. Recognizing that weeds thrive in particular conditions of low soil fertility, we will use custom soil tests and recommendations to amend the pasture soil to promote desirable forage species and increase hay quality. We expect that with the proper balance of soil nutrients, the percentage of forage species in the field will increase along with an increase in hay quality, while weed species decline, without the need for cultivation, reseeding, or herbicide application. We will quantify our results by measuring weed and forage species composition in three one-acre amended test plots and three one-acre unamended control plots. Forage species will be sampled and analyzed for nutritional content to compare hay quality in test and control plots. This study will take place during the 2011 and 2012 growing seasons in Mid-coast Maine, and the results shared with other farmers via an on-farm workshop, an off-site presentation, and a written project summary.

    Project objectives from proposal:

    This study will begin in spring 2011 and continue through September 2012, providing two full seasons of data collection. We will establish research plots in the Zephyr Hill Farm pasture arranged in a randomized complete block design, consisting of three replications of one acre test plots and three replications of one acre control plots. Initial soil tests will be obtained from each plot in spring 2011 to determine starting fertility levels; soil tests will be repeated in spring 2012 to monitor any changes and make necessary nutritional adjustments. Based on the soil tests, three test plots will receive custom blended soil amendments (applied with a fertilizer spreader) in late spring/early summer 2011 directed to encourage growth of pasture forages and increase hay quality. The remaining three control plots will not receive any amendments. Amendment blends will be formulated with the assistance of Mark Fulford.

    Species composition will be measured in each plot using the beaded string method (Northeast Cover Crop Handbook, Sarrantonio 1994), in which a string marked in one-meter increments is stretched across the plot in transects; the researcher records which species is growing beneath each mark. Weed and forage species composition will be measured three times throughout the growing season: once in May, before amending the soil, again in June during first-cut (of hay), and a third time in August during second-cut. To measure hay quality, plant tissue samples from each plot will be collected twice throughout the growing season, once in June and again in August, and sent to the University of Maine Analytical Laboratory and Maine Soil Testing Service for nutritional analysis that includes nitrogen, phosphorus, potassium, calcium, magnesium, aluminum, boron, copper, iron, manganese, and zinc levels. Plant tissue samples will be obtained by cutting every tenth plant (whether a weed or forage species) along the beaded string and bulking the cuttings as a representation of the entire plot. After plant sampling, plots will be mowed to simulate grazing and to prevent weed species from going to seed.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.