Pasture Management on Organic Dairy Farms: Assessing Pasture Quality and Productivity

eOrganic author:

Sarah Flack, Sarah Flack Consulting

Source:

Adapted with permission from: Mendenhall, K. (ed.) 2009. The organic dairy handbook: a comprehensive guide for the transition and beyond. Northeast Organic Farming Association of New York, Inc., Cobleskill, NY. (Available online at: http://www.nofany.org/organic-farming/technical-assistance/organic-dairy, verified 18 July 2012).

Introduction

Pastures do not suddenly become poor quality. It is a gradual decline over time, usually due to overgrazing damage, which encourages weed growth and reduces the more productive desirable grazing species. A knowledge of soil fertility and a good understanding of grazing management techniques, along with trained observational skills, are needed to develop this vital part of the organic system.

Assessing Pasture Quality

Assessing pasture quality improvement over time is a good way to measure the success of a grazing system. There are several useful systems of pasture condition or quality scoring, which involve scoring the same pastures each year to measure how the production of quality feed changes. It is also helpful to do this condition scoring several times each season and to then repeat them the next year, on the same dates, in the same pastures to consistently track changes over time (see Table 1). Some useful questions to ask when assessing pastures include the following.

  • Is all sunlight landing on the farm being captured, or are there areas of bare soil and nonproductive plants in the pastures?
  • Are soils fertile and biologically active so that plant health and the conversion of sunlight are maximized?
  • Does water cycle through the farm so it is available to the plants and cows when they need it while not creating erosion?
  • Is the livestock grazing system improving the farm’s ability to convert sunlight into high quality forages?
  • Are livestock harvesting forages efficiently and producing enough milk to meet farm goals?

Grazing Recordkeeping

Recordkeeping used for certification and/or general farm management can also be used to monitor pasture health and productivity. The following records may be used.

  • Check with the certifier to see what grazing records are required.
  • Keep records of the stored feeds (grain and forages) used to supplement pasture to show the certifier what percentage of their daily DMI is from pasture.
  • Keep records of when the grazing season starts and ends.
  • Records of when each pasture is grazed will provide information on farm regrowth periods so that pasture planning for next year can be more accurate.
  • If records include daily milk production, this may show patterns in animal performance and its relation to the grazing system.
  • Consider using one of the pasture quality or condition scoring systems to track changes in pasture quality over time.
  • There are very helpful methods to measure overall "cover" of pasture dry matter on the farm. One of these is the “grazing wedge” calculator found on the University of Missouri Extension webpage: http://grazingwedge.missouri.edu/

Improving Pastures

Before plowing and reseeding a grass/legume pasture, be sure that options for renovating and improving the field have not been overlooked. If a pasture is plowed and reseeded but the grazing management system is not changed, the reseeding will only provide a temporary solution to poor pasture quality.

An economical way to improve some areas may include frost-seeding clovers, changing the grazing management, mob stocking, improving aeration (using an aerator, Yeomans plow, or chisel plow), or adding compost or some other amendment to improve soil health. When reseeding is necessary as part of a rotation with annual crops or for another reason, choosing the right species is important. Selecting the right species, variety, or mix of species involves a consideration of soil pH, drainage, fertility, climate, crop palatability, weed pressure, harvest method, and the length of time the stand is needed.

Frost seeding can be a helpful method to introduce new pasture species to a permanent pasture. Frost seeding generally is less successful for grasses, but works well for white and red clover and involves broadcasting a small amount of seed per acre into the pasture in late fall or early spring. A few grass species such as perennial rye grass have been frost seeded with some success, but require good frost seeding conditions.

The following practices improve the success of frost seeding:

  • Use heavy fall grazing to control grass growth and create more open soil.
  • Test soils and fix imbalances that hamper legume growth. Pay particular attention to lime, potassium, boron, and phosphorus.
  • Seed in late winter or early spring.
  • White clover will persist longer than red clover. Consider frost seeding a mix of each.
Table 1. Pasture quality and condition score chart.

Directions: Walk through each pasture area on your farm and use this chart to assess the quality or score of each category. Rank each pasture area as poor, fair, good, or very good in each category. Include comments and descriptions of what you observe to help you track changes over time in your pastures. Consider monitoring soil health at the same time you check your pasture quality.
Date:
Category Pasture Area

Score (poor, fair, good, very good)

 Notes and Comments
Plant Diversity: How many different species of plants are in the pasture? A poor pasture will have few legumes and a small number of grass species. A good quality pasture will contain 2 or more legume species and many grass species.      
     
     
     
     
     
     
Plant Density: Poor density will have soil visible between the plants, whereas a good quality pasture will be higher density with a more complete cover.      
     
     
     
     
     
     
Palatability of Plants: Good quality pasture will contain most or all plants that are the species and at the stage of maturity cows prefer to graze. A poor quality pasture will contain nonpalatable weed species and other plants the cows will not eat.      
     
     
     
     
     
     
Plant Growth Rate: Ideally, pasture plants will grow vigorously throughout the growing season. There will normally be slower growth of the perennial species in midsummer. Pastures that are more drought prone, have poor soil fertility, or are overgrazed will be less vigorous and will show more seasonal variation.      
     
     
     
     
     
     

Also in This Series

This article is part of a series discussing pasture management on organic dairy farms. For more information, see the following articles.

References and Citations

  • Emmick, D., K. Hoffman, and R. Declue. 2000. Prescribed grazing and feeding management for lactating dairy cows. USDA Natural Resources Conservation Service, Syracuse, NY.
  • Murphy, W. 1998. Greener pastures on your side of the fence. Arriba Publications, Colchester, VT.
  • Robinson, J. 2004. Pasture perfect. Vashon Island Press, Vashon WA.
  • Smith, B. 1998. Moving ‘em: A guide to low stress animal handling. Graziers Hui, Kamuela, HI.
  • Undersander, D., M. Casler, and D. Cosgrove. 1996. Identifying pasture grasses. University of Wisconsin-Extension Bull. #A3637. University of WI, Madison, WI. Available online at: https://learningstore.extension.wisc.edu/products/identifying-pasture-grasses-p176 (verfied 25 Nov 2019).
  • Zartman, D. L. 1994. Intensive grazing seasonal dairying: The Mahoning County dairy program, 1987–1991. OARDC Research Bull. 1190 (1-49), OH Agric. Res. and Development Center, OH.

Additional Resources

Published March 15, 2013

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

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