By Mitch Stephenson
Planting perennial grasses on marginal dryland cropping areas has long been recommended as a sound conservation practice. Planting perennial grasses for conservation may also provide opportunities to increase livestock production.
Expectations for production of perennial grasses should follow the performance for crop production on a piece of land. That is, if an area was low producing for dryland crops, the potential for producing large amounts of perennial grasses is lower than if it were better-quality ground with high crop production.
Planting perennials is a costly endeavor and comes with a commitment to manage a piece of land as pasture rather than cropland for an extended period of time. As a result, a thorough economic analysis is warranted before tackling this type of project. This includes the cost of seed, planting and weed management, as well as the potential opportunity costs associated with the reduction in revenue from cropping systems and the potential gain from using the pasture for livestock grazing.
What should I plant?
Many seed companies have diverse mixtures that can be selected for perennial pastures. It is recommended that you talk with as many of these companies as possible to determine what types of grasses work best in your area.
Cool-season introduced grasses are often chosen because of ease of establishment, relatively good production early in the growing season and the ability of these species to take advantage of early spring precipitation. On dryland areas in western Nebraska, selecting species that are tolerant of dry conditions and thrive in the 14-to 16-inch precipitation zones is critical.
Some of these species include pubescent wheatgrass, western wheatgrass, intermediate wheatgrass, tall wheatgrass, wildryes, and smooth and meadow bromegrasses. Typically, simple mixes of two to four species are the best options for establishment and management.
When should I plant?
If you are considering planting cool-season introduced grasses, there is still time to get started for 2018. There are two optimal times to plant cool-season grasses, in the late summer from around Aug. 1 to Sept. 15 or in the spring from March 1 to April 30. Late-summer seedings depend on late-summer and fall rains, and seedings should not take place if the soils are dry or if there are projections of extended drought.
About 48% of the annual precipitation in western Nebraska falls from April 1 to June 30. Spring and early-summer precipitation, while difficult to predict, is the most important factor in the establishment of grasses following a spring planting. Climate projections like those found at the Climate Prediction Center can help make decisions on whether to plant this year or wait until conditions appear more favorable.
Summer annual weeds like kochia, marestail and yellow foxtail are typically more problematic with spring seedings compared to fall seedings. Planting early in the spring can give the grasses a competitive advantage over weeds.
If weeds become a problem and are overshadowing emerging grass tillers, they can be mowed at a relatively high clearance to reduce weed heights while still maintaining leaf area on the grasses. Herbicides like 2,4-D ester at a rate of 1 pint per acre can provide control of broadleaf weeds, but tillers of the seeded species should have at least five leaves and be over 6 to 8 inches tall before applying this herbicide. If grasses establish well in the first year, weeds will typically not be as big of a problem in following years. However, if weeds are present, controlling them will help the grass stand thicken and maintain production.
Planting into wheat or other small-grain stubble provides a suitable and firm seedbed for perennial grass establishment. Stubble also provides good erosion control while the seedlings are being established. It is important to delay planting for at least 30 days after grain harvest and to control volunteer growth before seeding perennial grasses.
What about management?
In the dryer conditions of western Nebraska, cool-season introduced grasses are typically not grazed the first year, but if there is strong establishment and adequate precipitation for growth, a very light graze may sometimes be taken late in the growing season. Late-summer seedings of perennial grasses should not be grazed before the next growing season.
In the second year, if establishment is sufficient and production is adequate, livestock can be grazed. Ideally, this would take place later in the growing season (after mid-June). Leaving at least 4 to 6 inches of residual stubble will ensure grasses have the leaf area to maintain photosynthetic growth later in the growing season.
A full grazing can usually take place during the third growing season after the planting of cool-season perennials. Allow the grass tillers to reach at least 5 to 6 inches before grazing in the spring, and rotate pastures to allow for regrowth on these tillers while there is still adequate soil moisture. Cool-season grasses typically have a bimodal growth curve with most of the growth occurring in the spring. But if late-summer and fall precipitation is available, substantial growth can occur during this time.
This fall growth is important for cool-season grasses to store energy and maintain reserves in winter, and grazing this regrowth very short can harm new tillers and potentially reduce yields the following year.
Perennial cool-season grasses are a good option to consider for conservation and livestock use on marginal cropland areas. Under dryland scenarios in western Nebraska, stocking rates of 0.5 to 1.0 animal unit months (AUM) per acre are typical estimates for stocking rates with proper management, but monitoring the establishment of the seeding and appropriately estimating the annual forage production will help in setting the right stocking rates long term.
Understanding the production potential of a piece of land also will help in making appropriate estimates for what to expect in terms of production. Monitoring the seeding, managing weeds and grazing conservatively in the first few years will help the grass establish.
Stephenson is a Nebraska Extension range management specialist. This report comes from UNL BeefWatch.