Establishing Perennial Grasses
Are you considering establishing a new field of perennial forage grasses this spring or renovating an existing field? Seed selection, seedbed preparation, fertilization, methods of seeding, time and rate of seeding, and weed control are all an important part of the process.
For cool-season grasses such smooth brome, wheatgrasses or orchardgrass, the planting period is typically mid-March into April. Planting in late April or May is suggested for warm-season grasses like big bluestem or switchgrass.
The seedbed for grasses should be firm, well-packed and free of large clods, with just enough loose surface soil for proper seed coverage. Good seed-to-soil contact is essential to maintain adequate moisture near the seeds. This moisture is necessary for germination and for the small root systems of young grass seedlings.
A companion crop such as oats with cool-season grasses can be used for seedling protection and to reduce soil erosion. Sandy soils or hilly sites are most likely to benefit from companion crops.
Grass seedlings grow slowly and compete poorly with weeds. The most frequent cause of seeding failure and slow establishment of warm- and cool-season grasses is poor weed control. If weeds are abundant, mowing can be used to reduce competition. Broadleaf weeds can be controlled in grass seedings using 2,4-D ester at a rate of 1 pt/A (4 lb of acid equivalent/gal). Do not spray 2,4-D until grass seedlings have at least five leaves.
For more information on this topic, see the Nebraska Extension NebGuide G1705, “Establishing Dryland Forage Grasses”.
Dry Winter Forage Irrigation
Extreme dry winter conditions have many alfalfa, wheat and other forage producers considering possible late winter irrigation. In many locations, stored subsoil moisture levels are very low, with some at least 5 inches below normal. So, dry winter conditions may trigger earlier irrigation.
However, until air temperatures consistently stay above 40ºF, it will likely be wise to delay irrigation for at least one month to protect irrigation equipment from freezing. Although irrigation equipment is generally safe to operate when temperatures are about 34ºF, there have been cases where 40ºF air temperatures have frozen outer pivots and created considerable equipment damage.
Also, early spring irrigation runs the risk of bringing wheat out of dormancy prematurely. If temperatures drop afterward, there is risk of potential late spring freezes damaging immature heads of early tillers. So, monitor temperature and field soil moisture to protect, wheat from winterkill/springkill and improve yield.
Usually, the target is to provide 3.0 to 4.0 inches per acre of available soil stored water to hydrate wheat during the winter months. Our Nebraska Extension NebGuide EC731, “Producing Irrigated Winter Wheat,” outlines wheat peak water development usage stages as:
- Jointing,
- Boot,
- Heading (flowering through kernel dough), and
- Final kernel development.
Of the 22 inches of normal total wheat crop water usage from snow, rain, soil stored and supplemental irrigation, only 3.0 to 4.0 inches will be needed for final kernel plumping. Based on peak wheat growth stages, plants will utilize about 0.23-inch per acre per day during the main growing season. Coarse textured (sandy) soils will require earlier and more frequent watering to reduce stress compared to other soil textures.
For alfalfa, producers may irrigate during April and May to fill the root zone without water runoff to promote healthy roots. Then, adjust supplemental irrigation based on soil stored water, evapotranspiration (ET) and rainfall, to provide about 6 inches per acre per target ton of alfalfa production. Our Nebraska Extension NebGuide G1778, “Irrigation Management and Crop Characteristics of Alfalfa” provides more details.
