C.O.R.N. Newsletter: 2021-06

Wheat fields are firming up across Ohio and topdressing with nitrogen fertilizer has started. We have had less precipitation than usual, and more livestock producers may be considering applying liquid swine manure as a topdress for wheat.

The key to applying the correct amount of manure to fertilize wheat is to know the manure’s nitrogen content. Most manure tests reveal total nitrogen, ammonia nitrogen and organic nitrogen amounts. The ammonia nitrogen portion is readily available for plant growth. The organic nitrogen portion takes considerably longer to mineralize and generally will not be available when wheat uptakes the majority of its nitrogen before mid-June.

Most deep-pit swine finishing manure will contain between 30 and 40 pounds of ammonia nitrogen per 1,000 gallons. Finishing buildings with bowl waters and other water conservation systems can result in nitrogen amounts towards the upper end of this range. Finishing buildings with fixed nipple waters and surface water occasionally entering the pit can result in nitrogen amounts towards the lower end of this range.

In past years, some farmers have used sow manure to topdress wheat. Just know the nitrogen amount in sow manure will be much lower than swine finishing manure.

In university research, we have used both manure tankers and drag hoses when topdressing wheat. The concern with manure tankers is soil compaction, especially on heavy soils. The drag hose seemed to work well wherever it was used.

The typical application rate for liquid swine finishing manure on wheat is 4,000 gallons per acre. Wheat removes 0.49 pounds of P2O5 per bushel harvested. When also harvesting the wheat straw, a ton of wheat straw contains between three and four pounds of P2O5. So, a 100 bushel wheat crop with one ton of straw also removed would withdraw about 52 pounds of P2O5 per acre. This is likely about the same amount of P2O5 as 4,000 gallons of swine finishing manure would contain but review your manure test to make this determination.

When applying livestock manure to wheat it’s recommended to follow the NRCS #590 Waste Utilization Standard to minimize potential environmental impacts. This standard includes a 35 foot wide vegetative strip setback from ditches and streams. Applicators in the Western Lake Erie Basin also need to look at the weather forecast to be certain there is not greater than a 50 percent chance of a half-inch of rain in the 24 hours following manure application when surface applying. Print this forecast so you have proof in the event of a surprise rain downpour.

Early spring provides one of the two preferred times to seed perennial cool-season forages, the other being late summer. The outlook for this spring is for probabilities of above average precipitation in April and May. Planting opportunities will likely be few and short. An accompanying article on preparing now for planting along with the following 10 steps to follow on the day you plant will help improve chances for successful forage establishment.

1. Check now to make sure soil pH and fertility are in the recommended ranges.  Follow the Tri-state Soil Fertility Recommendations (https://forages.osu.edu/forage-management/soil-fertility-forages) .  Forages are more productive where soil pH is above 6.0, but for alfalfa it should be 6.5 – 6.8. Soil phosphorus should be at least 20 ppm for grasses and 30 ppm for legumes, while minimum soil potassium should be 100 ppm for sandy soils less than 5 CEC or 120 ppm on all other soils. If seedings are to include alfalfa, and soil pH is not at least 6.5, it would be best to apply lime now and delay establishing alfalfa until late summer (plant an annual grass forage in the interim).
2. Plant high quality seed of known varietal source adapted to our region. Planting “common” seed (variety not stated) usually proves to be a very poor investment, yielding less even in the first or second year and having shorter stand life. Be mindful of how much seed coating is present on the seed you are planting. Many of the new alfalfa varieties are sold with a 34% clay coating by weight, so your actual pure live seed rate would be dramatically reduced if you don’t adjust for the seed coating.
3. Calibrate forage seeders ahead of time. Seed flow can vary greatly for different varieties and depending on the seed treatment and coatings applied. A good video on this entitled “Drill Calibration” is at https://forages.osu.edu/video/.
4. Prepare a good seedbed as soon as soils are fit in April. The ideal seedbed for conventional seedings is smooth, firm, and weed-free. Don’t overwork the soil. Too much tillage depletes moisture and increases the risk of surface crusting. Firm the seedbed before seeding to ensure good seed-soil contact and reduce the rate of drying in the seed zone. Cultipackers and cultimulchers are excellent implements for firming the soil. If residue cover is more than 35% use a no-till drill. No-till seeding is an excellent choice where soil erosion is a hazard. No-till forage seedings are most successful on silt loam soils with good drainage and are more difficult on clay soils or poorly drained soils. You will want no-till fields to be smooth because you do not want to bounce over them for all the years of this stand!
5. Try to finish seeding by the end of April in southern Ohio and by the first of May in northern Ohio. Timely planting gives forage seedlings the jump on weeds and the forages become established before summer stress sets in. Weed pressure increases with later plantings, and forages will not have as strong a root system developed by early summer when conditions can turn dry and hot. Later plantings also yield less, so if planting is delayed, it might be better to plant a summer annual and establish the perennial forages in August.
6. Plant seed shallow (¼ to ½ inch deep) in good contact with the soil. Stop and check the actual depth of the seed in the field when you first start planting. This is especially important with no-till drills. In my experience, seeding some seed on the surface indicates most of the seed is about at the right depth.
7. When seeding into a tilled seedbed, drills with press wheels are the best choice. When seeding without press wheels or when broadcasting seed, cultipack before and after dropping the seed, preferably in the same direction the seeder was driven.
8. In fields with little erosion hazard, direct seedings without a companion crop in the spring allows harvesting two or three crops of high-quality forage in the seeding year, particularly when seeding alfalfa and red clover. For conventional seedings on erosion prone fields, a small grain companion crop can reduce the erosion hazard and will also help compete with weeds. Companion crops like oat can also help on soils prone to surface crusting. Companion crops usually increase total forage tonnage in the seeding year, but forage quality will be lower than direct seeded legumes. Take the following precautions to avoid excessive competition of the companion crop with forage seedlings: (i) use early-maturing, short, and stiff-strawed small grain varieties, (ii) plant small grains at 1.5-2.0 bu/A, (iii) remove companion crop as early pasture or silage, and (iv) do not apply additional nitrogen to the companion crop.
9. During the first 6 to 8 weeks after seeding, scout new seedings weekly for any developing weed or insect problems. Weed competition during the first six weeks is most damaging to stand establishment. Potato leafhopper damage on legumes in particular can be a concern beginning in late May to early June.
10. The first harvest of the new seeding should generally be delayed until early flowering of legumes (approximately 60 days after emergence) unless weeds were not controlled adequately and are threatening to smother the stand. For pure grass seedings, generally harvest after 70 days from planting, unless weeds are encroaching in which case the stand should be clipped earlier to avoid weed seed production.