Due to the drought of last year, many producers are finding forage supplies to be very tight until first crop harvest begins. We are not having an early spring, which will delay first crop harvest as well as early seeding of small grains. What are different options to increase early forage produced on your operation? Whether we need lactating cow, dry cow, growing heifer or bred heifer forage changes our approach and our priorities.
One of the first tasks to be done is to check your current inventories for supply and quality. This includes haylage, dry hay and corn silage. How much flexibility do you have to shift to feeding greater or lesser amounts of the current inventory? An early assessment of current hay fields will be important to determine if there have been winter kill or drought effects on survival and yield potential of the stand. Soil temperature needs to be above 41Â°F for alfalfa to break dormancy. Grass will begin growing even sooner. Work with your agronomist to dig up some alfalfa plants and look at root health. Count green and growing stems. If there are over 50 growing stems per square foot, you should have full yield potential. If there are less than 40 stems per square foot, there will be a yield reduction.
Is there pasture available for some or all of the animals? If soil tests indicate, early season applications of fertilizer will help to improve yields. With cool season grasses, an early season application of nitrogen to pastures is usually a profitable practice and increases yield at the most productive growing time. A split application of nitrogen at three different times makes the best use with the least loss of nitrogen.
If you want to increase total forage yield and provide early forage, using a small grain nurse crop for new seeding is the best way to go. Most research conducted in the Upper Midwest would show typical yields of 2 to 3 tons of dry matter of forage per acre. Early maturing varieties of barley, oats or triticale are recommended as nurse crops if you intend to harvest as forage; two bushels per acre is the seeding rate. Peas are sometimes added to the small grain at 30 to 50 pounds per acre. You may be able to buy these premixed and then plant at 100 pounds per acre. Small grain crops, with or without peas can be sown as soon as the soil is able to be worked in the spring.
Which species you use does not matter as much for forage quality as stage of maturity at harvest does. Wisconsin research done about 20 years ago showed oats or barley harvested at the flag leaf or early boot stage of maturity would test 13 to 14% CP and 52 to 58% NDF. Small grains such as oats are considered cool season grasses. Harvesting in early- to mid-June has several advantages. First, most of the forage growth is in the cool spring, leading to higher quality forage. Digestible NDF and CP will be higher. Secondly, the nurse crop is removed sooner to decrease competition for moisture and sunlight for the new alfalfa seeding. When peas are added, often the dry matter yield does not increase significantly but palatability and forage quality are generally improved. Adding peas to the mix would increase CP 2 to 3% and decrease NDF 3 to 5%.
One of the criticisms of using a nurse crop, especially if peas are used in the mix, is the difficulty in getting the forage dry enough to chop. It is critically important to lay the swath as wide as possible. This may require removing the discharge deflectors in order to get the swath as wide as the conditioner rolls. It is preferable to have the swath as wide as possible, even if you have to drive on the swath to mow. The drying rate is so improved that chopping time may be reduced by 25 to 50%. This same technique is also being used for alfalfa harvest and it is allowing harvest of 60 to 65% moisture haylage within 12 hours of cutting.
If a hay field yields poorly at first cutting, another decision has to be made: Is it worth keeping the rest of the year? One alternative would be to plant a BMR-6 type of sorghum-sudan grass. Sorghum-sudan grass is a warm season grass much like corn. It grows best in warm soil, warm temperature, long days and adequate rain. It does need nitrogen and is a good crop in a nutrient management plan. We do not recommend sowing sorghum-sudan grass in soil temperature below 60Â°F because it will not germinate. I recommend sowing 25 to 30 pounds per acre using a grain drill and planted at a depth of 1 to 1.5 inches. However, with good growing conditions, dry matter yields can exceed 5 to 6 tons dry matter per acre with a two cut system. I recommend cutting before the plant heads out, much like we do for small grain forage, at about 3 to 4 feet tall. Again, sorghum-sudan is a lush plant that needs to be conditioned and laid out in as wide a swath as possible and merged for chopping.
Have a safe spring and let's hope for plenty of rain this growing season at all the right time.
-Jim Paulson, Dairy Extension Educator, University of Minnesota