A Guide to Pasture Health
Biodiversity and Well-Managed Pastures

Simply put, pastures are fenced in grassed areas on farms where animals graze. But pastures are much more than a stand of grass like you might find in someone’s front lawn. Pastures have specific plant species that differ from a typical lawn and provide balanced nutrition for livestock. They are also managed like crop fields because farms that are able to maximize pasture production can provide important nutritional support for animals as well as economic support to their operation by reducing the need to purchase feed off-site.

Well-managed pastures can improve:
  • Animal nutrition
  • Stormwater management
  • Farm biodiversity, including increasing pollinator presence
  • Soil health
A healthy pasture with appropriate grass length for horse grazing | Photo source: Maryland Extension

How Local Farms Use Pastures

In Pennsylvania all livestock operations are required to have either a Nutrient Management Plan or a Manure Management Plan, depending on animal density. These plans ensure that manure and nutrient runoff do not flow into streams and waterways and help to support conservation efforts on farms. As part of these plans, pastures can be a beneficial way to ensure animals are getting the exercise, nutrition and care they deserve.

Pastures themselves have particular management requirements under the Nutrient and Manure Management Programs, most notably pastures are required to maintain a minimum of 3” of dense vegetative cover. Farmers, especially those working in small spaces, can sometimes struggle with effective rotational grazing and pasture management. As more farmers consider the financial, environmental and animal health benefits, learning tricks and trade secrets for successful pastured systems is a popular subject.

Pastures and Biodiversity

First, it’s important to recognize that a pasture is an ecological system. Like all systems, they require balance between inputs and outputs to keep the system in check. Biodiversity, in particular, enhances a pasture’s capacity to perform ecological functions, such as recycling nutrients, production of diverse food and feed for livestock, regulation of local hydrological processes and habitat for other beneficial critters. Biodiversity is not only an important tool to protect plant and animal communities, it also can boost productivity because different species reach maturity at different points in a season. In addition, a variety of species can improve pasture forage because of the nutritional composition of different plants. A good first step in improving the biodiversity and ecological capacity of pastures is to evaluate what is already there.

One method of evaluating existing pasture conditions comes from Conservation Biologist Alexis Russel from Aryshire Farms in Northern Virginia. At a recent presentation at the Pennsylvania Sustainable Agriculture (PASA) Conference in February, Russel highlighted accessible techniques for evaluating change, biodiversity and overall health of pastures with simple observations.

How to see if your pasture is healthy:

Look at snapshots of your pasture using a 1x1 meter PVC frame. Take note of the following:
  • Bare spots or signs of erosion
  • Plant species diversity
  • Presence of insects
  • Thickness of vegetation
Take pictures at different times during the growing season of the same pasture to note changes in pasture health and how any changes might correlate to management decisions.

An overgrazed horse pasture | Photo source: New Jersey Extension

Choosing Seeds for Biodiversity

There is not a single path for improving the biodiversity and health of pastures, but noting plant species diversity and finding ways to seed-in greater variety are examples of next steps.

When looking for pasture seed mixes, think about choosing:
  • Seed blends that incorporate 10 or more different species
  • Native grass and wildflower species, which are well-suited for our climate and soil conditions, produce hearty pastures for year-round use and create pollinator habitat

Most importantly, pasture improvements take time. Pastures can fall into disrepair very quickly, especially when livestock are allowed to spend too much time in one field. An overgrazed pasture will have many places where soil shows through and might even have larger bare spots. The grass itself will be short and struggle to recuperate, even when animals are not grazing. Over time, an overgrazed pasture will likely become host to weeds and other undesirable plant species that can be difficult to remove. The good news is: Pastures can be rehabilitated.

It can take time and careful planning to bring pastures back to full health and productivity. When re-establishing pastures, avoid the temptation to return livestock to the field as soon as new seed starts greening the pasture again. Allowing at least 6” of grass to grow helps plant roots firmly establish to withstand the stress of grazing. Taller grasses also have a different distribution of nutrition than shorter grasses. Shorter grasses have more sugars that can be tasty treats, but can also lead to health problems in some animals.

Pastures can be a great tool on a farm, especially when properly managed.

Pasture grass growth and recovery | Photo source

Have other questions about pasture health and how your pastures can star in your Nutrient and Manure Management plans? Contact Riley Sunday at rsunday@accdpa.org.