As you get ready for fall seedings, there are two important points to consider: seeding rate and planting date can both mean the difference between success and failure in crop establishment. Timing and amount are both critical. Here are a few factors involved:
- Size of the Seed – a smaller seed means a lower seeding rate (pounds per acre) than a crop with a larger seed to achieve a comparable population; smaller seed size also means shallower seeding depths.
- Balance of Species – your needs and goals for the crop determines what proportion of each species in the mix is most suitable
- Conditions – more challenging weather and soil conditions (including high-residue no-till situa-tions) often dictate a higher seeding rate.
- Intended Use – a cover crop often means a lower seeding rate than growing the same crop as both a cover and forage.
Seeding rate and seeding date are mutually influential. For example, a later seeding date with a grass crop might mean less tillering in the fall, demanding a higher seeding rate to achieve the same ground cover.
One of the highest-yielding winter annual mixes we observed this spring was TriCal 815 (a lower–growing, dense triticale) mixed with Crimson Clover. The sweet spot for seeding rate turned out to be about 100#/acre of TriCal 815 and 25#/acre of Crimson. If you use more triticale or less clover, the clover gets-drowned out and play little role in ultimate yield. This may seem like a high rate for clover, but keep in mind that Crimson has a larger seed than most other clovers.
An earlier planting date means better growth and establishment in the fall, so you can reduce the seeding rate slightly. Crimson clover can be planted at 15-20 #/acre if you get it in the ground in early.
Forage Oats mixed with Daikon Radish is a useful cover crop that provides winter-killed ground cover over winter, as well as a grazing crop in the fall. In this combination, we recommend 40-60 lbs. of oats; 40 #/acre of oats as a cover crop, and 60 #/acre of oats in a grazing scenario. In general, 50 lbs. of oats with 6-8 #/acre of radish makes a good mix.
For a grain farmer using it as a winter-killed cover crop, we would recommend slightly less oats and more radish, about 40 lbs. of oats and 6-10 lbs. of radish. The higher radish seeding rate gives you a greater number of thinner radish tap roots that can grow deep into the soil, ideal for breaking up hard pans.
A grazier or forage grower, however, is usually not looking for soil improvement as a primary goal and should plant a higher proportion of oats to get the best dry matter yield for feeding (radishes will provide a nutritious high protein supplemental forage as a component in the mix, but the radish leaves are high in moisture and less dense in dry matter) This means cutting back the radish to 4-6 lbs. and increasing the oats to 60 lbs to get both digestible fiber from the oats and a nutritious brassica leaf forage from the radish.
Oats can be combined with other forage brassicas (hybrids or turnips) for fall grazing. The best combinations for maximum biomass for grazing in about 60 days are a combination of oats at 2 Bushel per acre (64 lbs.), along with 4 to 6 lbs. of turnips (Appin or Barkant turnip). Appin is quicker than Barkant. Or plant the oats with 2 to 3 lbs. of other forage brassica (T-Raptor or Pasja) The daikon radish could be used as well.
To gain the maximum amount of biomass for grazing, the optimum planting date is about six to eight weeks prior to wheat planting date. With later plantings, the oats’ seeding rate can be increased, which makes up some biomass with more plants per square foot (as opposed to having the oats grow more from the increased growing temperatures when planted earlier). T-Raptor, Appin and Barkant are the preferred brassicas to pair with oats for quick growth of biomass.
Planting dates that stretch later into the fall produce far less cover crop biomass, heights, and ground cover. The month’s difference between mid-September and mid to late October can reduce biomass by 50%. Earlier planting means faster seed germination and growth, and allows the crop to become better established prior to fall dormancy. This provides maximum groundcover. An earlier planting also helps buffer against adverse fall weather. Delaying planting by a day in the fall really shows up negatively in the spring harvest.
Seeding rate is sometimes, but not consistently, a predictor of yield and establishment. Small grains often make up for low seeding rates with more abundant tillers –more cost-effective for you. When seeding a cover crop in the fall, grabbing an early planting window is probably more critical than a higher seeding rate, but you may have no choice and be forced to make up for late planting with a higher rate.
We’ve also found that with some small grains like wheat and barley, increasing the seeding rate from 100 lbs to 130 lbs. doesn’t make a whole lot of difference to final tonnage (if planted in a timely manner), but adding another species, like crimson clover at 20-25 lbs., can significantly improve yield.