Prince William Soil & Water Conservation District
By Kate Norris
Pasture Management 101/Part I
Green pastures start with well-nourished soil. Have you ever considered the quality of your soil? Each soil is unique, with its own name, potential, and limitations. Most farms have several types of soil. These soils have been identified and labeled by soil scientists, looking somewhat like interlocking puzzle pieces, and can be viewed in a soil survey map. Many of the soils in our area of northern Virginia have high clay content and tend to stay wet. These soils require more intense management to produce good ground cover and forage. Proper management, including managing nutrient levels and pH, proper seed selection, and thoughtful grazing will bring even an inherently poorly productive pasture to its full potential yield.Nutrient management is the practice of achieving and maintaining soil nutrient levels and pH based on your crop (pasture) needs to produce maximum yields. A soil survey (a document available from your local Conservation District office) will provide information about the capabilities of your soils, but the only way to determine the soil nutrient levels and pH is by having the soil in each field analyzed. The process of soil sampling involves taking several samples of soil with a soil probe or spade to a depth of 2-3". Take care to avoid odd areas of a field, such as areas with high manure concentration (i.e., hay feeding areas), that may skew your results. A sample should represent as uniform an area as possible, in terms of crop/forage type and past management. All samples from a field should then be combined and from that mixture a smaller sample, representative of the entire field, is submitted to a soil testing lab for analysis. Prepare a sample for each field. You may want to sample any "trouble spots" separately. The analysis, which is free through VA Tech (check with local universities with agricultural departments), includes phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) levels, and soil pH. Fertilizer and lime recommendations are provided based on the analysis. Farms utilizing manure as a fertilizer can contact your Conservation District for manure sampling information and recommendations.
The timing and application of fertilizer and lime involves careful consideration. Blending the right fertilizer products to meet your needs can be tricky. The District, as well as local farm supply stores, can help. Under-application of nutrients will not produce the maximum yields you desire and conversely over-application results in an excess of nutrients beyond which your grasses can utilize. Over application has a high cost on water quality,creating nutrient-rich runoff and a drain on your finances.
Fertilizers should only be applied when grasses are actively growing; usually March or August is best. Fall application will result in better root growth, helping grasses survive the winter as well as drought conditions. Never apply fertilizers, including manure, to frozen or saturated ground. If you plan to apply fertilizers yourself, take the time to calibrate your spreading equipment. Again, the District can help you with this.
Lime is important. If you are on a tight budget, skip the fertilizer and apply lime to achieve the proper soil pH. If your soil pH isn't correct, the nutrients already in the soil will be "locked up"and unable to be utilized by your forages. Spreading fertilizer on a field that needs lime is a waste of time and money. Often times lime application, to correct soil pH, is very beneficial for weed control. Once you achieve proper pH, aggressive grasses such as fescue may out-compete your weeds.
Lime can be applied at any time of the year. It is applied by the ton, so spreading lime yourself isn't always feasible. If you plan to have a farm services business apply your lime, find out what the minimum delivery charge is. If you don't need a full truckload of lime, you have a couple of options. First, it's okay to double your spreading rate without having a negative impact on the environment. An alternative is to coordinate with your neighbors and share a load of lime. The sooner you spread your lime the better. A surface application of pulverized lime will take nearly a year to become incorporated into the soil and fully benefit your pastures. Overall, lime is an inexpensive input that goes a long way to help pasture output.
Pasture Management 101/Part I
Part I addressed soil quality, assessing nutrient levels, and the application of lime and fertilizer. Now your soil is ready, what do you plant? It depends. Conservation Districts and University Cooperative Extension agents can provide you with specific seed mixtures that will fit your operation and soil capabilities. Generally, a mixture that contains KY 31 Tall Fescue will be productive in variety of situations. It's aggressive, tolerant of both wetness and drought, and more likely to survive some overgrazing. Unfortunately, its resilience is largely due to its infection with an endophyte toxin that can cause problems for broodmares. Most of the toxin is in the seed head, so keeping your pastures grazed down below 6" as well as including other grasses such as orchardgrass and bluegrass will greatly reduce possible exposure.For farms that have broodmares, hayland, poorly drained soils, a high stocking rate or other specific concerns, I recommend checking with the District or Extension. Be wary of generic"pasture mixes." These mixes usually contain forages such as timothy, alfalfa, or others that are not well suited to grazing. You end up paying more for a variety of seeds that tend to be less productive than a custom mix recommended by a local agronomist.
You've invested a considerable amount of time and money in your pastures by this point. How will you manage grazing to protect your investment? Thoughtful grazing. Develop a rotational grazing system. By subdividing your fields you can graze smaller sections more intensely, forcing the horses to graze more uniformly with less waste. While grazing the herd in one area, the others are allowed to rest and re-grow (grazing one horse per paddock in multiple paddocks simultaneously doesn't count!). When grass in the current grazing area gets below 4" it's time to move the horses to another area. When all the pastures are below 4", or in wet weather, rotate the horses into a "sacrifice area."
A sacrifice area is a confinement area, with or without a surface treatment such as bluestone dust or wood chips, on which you do not expect to grow grass. You are sacrificing the groundcover in one area for the good of the majority of the grazing system. Farms with less than three acres per horse will have a difficult time maintaining healthy pastures without utilizing a sacrifice area, no matter how productive the soil. If you have more than one turnout group you will need multiple sacrifice areas.
Interior fencing to subdivide pastures need not be expensive. One or two strands of electrified wire, tape, or braid will easily contain most horses. A simple interior fence with a solar or electric charger can cost less than $1.50 per foot, installed. Temporary fencing also gives you the flexibility to change the size and number of pastures, depending on a variety of factors, throughout the year.
Green pastures require careful management, especially if you have more horses than acreage. The key elements are understanding (and accepting) your soil's potential and then utilizing nutrient and grazing land management principles to reach optimal pasture yields. Plan now for greener pastures tomorrow. Contact your local Conservation District to schedule a pasture consultation with soil sampling or find our where you can pick up a soil sampling kit.