Sow and Grow: Grass choice is key to spring pasture management
As spring rolls in (we hope), pastures and other forage crops will begin to green up. With small grain crops going in soon, and lambing and calving underway, many farmers are gearing up for another busy growing season. I challenge you however, to spend some time focusing on spring pasture management; now is the time to evaluate stands and determine if action needs taken.
The first step of pasture management is to determine which grass species are growing on your land. If you have a mixture of cool and warm season pastures, it’s best practice to graze the cool seasons species first (ex: smooth brome or crested wheatgrass). These grasses come up early and will put on early season growth quite rapidly; however, it is best practice to avoid grazing until the 3-leaf stage. Then, later in the season, move livestock to warm season grasses (ex: big bluestem or little bluestem) as they need warmer temperatures to establish and put on tonnage. Avoid grazing most warm season grasses until they reach the 3.5-4 leaf stage.
Determining when grasses will be ready to graze is dependent upon the year and is often measured in growing degree-days. We can estimate growth based on weather station data and approximate growing degree-days at a particular location, but best practice is to get out to the pasture and examine growth progress.
Another important consideration is pest management. In the spring, weeds are the biggest concern in pastures. Grazing management, mowing/clipping, herbicides, hand chopping, digging, burning, and biological control are all ways to control weeds in a pasture setting. Many studies have shown that reducing weed pests in pastures yields more tonnage and positive economic returns. There are many ways to control grass weeds, but the key is to pay attention to your pastures and use control methods early.
Herbicides are quite common in the control of pasture weeds; using the right herbicides early in the season will prevent flowering and seed production. Both biennial weeds (musk thistle, bull thistle, wild carrot, etc.) and winter annual weeds (mustards, marestail, etc.) are most susceptible to herbicide control in the early spring.
Getting a herbicide application on early is important to prevent biennials from bolting, so if you didn’t use any control measures last fall, the ideal control time will be very soon when plants are small and more easily killed. Early control measures for winter annuals can be just as important, as they put on significant growth in the early spring and flower quickly, reducing herbicide effectiveness.
If you have issues with perennial weeds like Canada thistle, herbicide control will be more effective a bit later in the summer after they reach the bud stage. Keep in mind, that if you have patches of weed infestations that do not cover an entire pasture, spot spraying those areas is likely most appropriate to avoid using pesticides unnecessarily. For suggested herbicides that fit your situation, visit extension.sdstate.edu and search “pasture and range weed control”.
Fertilizing pastures is a bit more delicate of an issue. It is good practice to soil test pastures and check macronutrient levels in the soil. Pastures will under produce if we short them on nutrients, and if nutrients are over-applied, we are wasting resources. Grasses respond well to applied nitrogen fertilizers, but it is important to check that adequate P and K levels have been met before applying nitrogen to ensure applied fertilizer profitability.
Of course, much like cultivated row crops, N response in pastures depends on many factors: rate of fertilizer, form, weather, soils, timing of application, etc. Although N can be applied throughout the growing season, we recommend spring (April) pasture applications of N. This will boost spring productivity and can help grasses to cycle those applied nutrients (after grass is grazed and manure is deposited) later in the season as well. On the other hand, if you have warm season pastures, adequate N is needed throughout the hot summer months (June-August), meaning a mid-May application is likely most appropriate.
The SDSU Fertilizer Recommendations guide suggests 25lbs of Nitrogen per 1 ton of grass yield goal. If you are unsure of your pasture production, you can attempt to measure it for future seasons by taking grass clippings in a known, ungrazed area (where all other management takes place as it normally would). Specific recommendations on P, K and other nutrients can be found in the SDSU “Fertilizer Recommendations Guide” located at our website, extension.sdstate.edu.
- Ag Economic Dialogues webinar- March 17, 10am CT, free registration
- Landowner Prescribed Fire Intro Class @ Watertown- March 21, 5:30-8:30pm CT, free registration
- Soy 100 @ Brookings- March 23, 9:30am-2:10pm CT, free registration
- Landowner Prescribed Fire Intro Class @ Yankton- March 23, 5:30-8:30pm CT, free registration
- Northern Plains Forage Association Annual Meeting @ Sioux Falls- March 29 or March 30 (choose one), during Central Plains Dairy Expo from 2-3pm CT, no registration required
Sara Bauder is an agronomy field specialist with SDSU Extnesion.