by Joel Bagg, Forage Specialist & Peter Johnson, Cereals Specialist, OMAF and MRA
Summer seeding annual forages can be a useful low-cost option for producing extra feed, either as an emergency forage or a regular double-crop option. These forages include cool-season cereals (oats, barley, triticale) and cereal-pea mixtures, as well as warm-season sorghums, sorghum-sudangrass and millets (pearl, Japanese). Record acreages of these emergency annual forages were seeded last summer, and provided farmers with a “big save” in meeting their forage needs. Yields and nutrient quality were generally excellent, with high volumes of palatable quality baleage and silage made.
Oats have been the species most frequently used, as a low cost, low risk approach. They can be seeded in late-July or early-August following wheat and spring cereal harvest for an early-October harvest. Oats can make good feed when harvested at the correct stage of maturity and made into “oatlage” or baleage. Oats are more frost tolerant in the fall than sorghums, and can continue growth after some frost. The challenges can sometimes be lack of adequate moisture in August, and having dry enough weather in October for adequate wilting. Oats can be pastured if fence is available.
Oats, Barley, Triticale, Peas?
Many find that oat forage is the most palatable of the cereals. Some producers avoid barley and triticale because of concerns about feeding the awns. Oats tend to out-yield barley when establishment conditions are poor. Triticale seed can be more expensive and difficult to source. Spring wheat generally yields poorly when summer seeded. At the same stage of maturity, oats, barley and triticale are very similar in feed quality. Of the cereals, oats are the most readily available, and usually give the best yields and returns for the dollars invested.
Peas can be added where higher forage quality is required. Cereal-pea mixtures are popular as a spring seeded companion crop. Peas added to cereals improve forage quality, but do not necessarily increase yields. Summer seeded peas dislike hot, dry conditions even more than cereals. Pea growth is often quite variable depending on moisture. Peas are more succulent and higher in moisture than oats, and can be very difficult to wilt in the fall. Pea mixtures may lie in the swath for an extended period of time with the risk of being rained-on. Lush cereal-pea mixtures can be difficult to cut. Seed is more expensive. Despite these concerns, peas improve forage quality where meeting high nutritional requirements is a priority, such as for high producing dairy cows. If a cereal-pea mixture is sown to improve feed quality, at least 50% should be peas, with a total seeding rate of about 110 lbs/ac. This will typically increase crude protein by 2 – 4% and decrease NDF by 2 – 4.5% over straight cereals. Refer to “Forage Production From Spring Cereals and Cereal-Pea Mixtures” www.omafra.gov.on.ca/english/crops/facts/98-041.htm .
Cereals Versus Sorghums or Millets?
Sorghums are much more tolerant of hot dry summer weather than cereals. In situations where seeding dates are very early (early-July) allowing for harvest maturity (50 – 60 days) before frost, sorghums will yield better than cereals. As cool-season grasses, oats are not very tolerant of hot dry weather and do not tiller and grow well in these conditions. Refer to “Forage Sorghum-sudangrass” http://www.omafra.gov.on.ca/english/crops/facts/98-043.htm .
However, cereals planted after late-July may start slowly but finish strongly in the fall, and can perform very well. Warm-season grasses, such as sorghums, sorghum-sudans and millets do not grow well in cooler fall weather, and are very sensitive to frost. Once they are killed by that first frost, there is no further growth, which limits yield potential. Also after frost, there is a very narrow harvest window before forage quality drops significantly. There are also some concerns about potential prussic acid poisoning with frosted sorghums, particularly if pasturing. Oats will out-perform sorghums in cooler, wet fall weather, and are much more tolerant to hard frosts. They are not killed by frost until -9°C, enabling growth into very late fall, and a much wider harvest window.
Oats normally require about 60 days of growth following germination to reach the boot-stage. However, summer seeded oats tend to mature more slowly as days shorten in the fall, so may require an additional 10 days or so. Oats seeded on August 1st would typically be ready to harvest in early-October.
Many prefer to no-till drill oats into wheat stubble to save time and moisture. Alternative seeding methods are to broadcast the oats and then incorporate them with a light disc or cultivator, or to seed into a prepared seedbed using a conventional drill. Summer seeded oats for forage are commonly seeded at about 65 – 100 lbs per acre (2 – 3 bu/ac). High seeding rates have little impact on improving yields. Cereal-pea mixtures (minimum 50% peas) are seeded at about 110 lbs/ac.
Seeding after winter wheat is harvested can be a good opportunity, but competition from volunteer wheat can be a significant problem. Without vernalization winter wheat will not form a stem in the fall to provide significant growth and yields are very limited. A lot of volunteer wheat can result when light grain goes through the combine, such as fusarium infection situations. One approach to reduce the problem is to do some light tillage behind the combine swath to encourage the grain to germinate. A burndown with glyphosate 7 – 10 days later will remove much of the volunteer grain.
There are oat varieties specifically marketed as “forage” varieties. They are marketed as higher yielding, but tend to be later maturing, and with less disease resistance. Preliminary data suggests that western oat varieties respond differently in Ontario conditions and head very late, which results in lower yields but higher nutrient quality. Ontario does not have a third-party forage oat variety testing program to evaluate variety performance and seed company claims. Many producers use double-cleaned or weed-free bin-run oats to minimize costs.
Apply 50 lbs/acre of actual nitrogen (N) before tillering (3 weeks after germination). N is essential for adequate growth and has a major impact on cereal forage yields, particularly oats. Manure or fertilizer can supply N, but growth without nitrogen will be very disappointing. Applying nitrogen also improves crude protein levels. Research is underway to fine-tune N recommendations. (Cover Crops For Emergency Forage – Interim Report www.ontariosoilcrop.org/docs/v9crpadv_for3-2012_cover_crops_for_emergency_forages_interim_report.pdf )
Phosphorus (P) and potassium (K) will be removed in the forage. It is not essential to replace or add any P or K during the growth of an emergency forage crop, but it should be accounted for in the rotation. At current commercial fertilizer prices, the value of the P and K removed in the crop is typically in the 1.3 to 1.7¢/lb of dry matter range. This should be considered when pricing these crops.
Crown rust is a potential problem in summer seeded oats. Crown rust can defoliate the oat crop and decimate yields if infection is severe. Monitor and apply a fungicide if disease levels warrant. Refer to OMAFRA Publication 812, Field Crop Protection Guide www.omafra.gov.on.ca/english/crops/pub812/4ocrust.htm
Harvest Moisture & Fermentation
Wilting late-summer seeded oats to an acceptable moisture level to allow for a good fermentation during October weather can be challenging. Fall weather tends to be cooler, days are shorter, dews are heavy, and “rain delays” while lying in a swath can be significant, resulting in much slower and more difficult drying. Heavy crops and cereal-pea mixtures are especially challenging. Generally, silage over 70% moisture and baleage over 55% moisture tends to be more prone to inefficient clostridial fermentations, especially if they were raked and soil was incorporated into the swath. This leads to high levels of butyric acid and “stinky, slimy” feed with reduced palatability and quality. Refer to “Silage Fermentation Problems” http://fieldcropnews.com/?p=5592. Last year (2012), farmers continued to harvest forage cereals and hay fields in late-October and into November, when weather suitable for wilting was almost non-existent. However with colder temperatures, spoilage was minimal if fed over winter. Grazing this growth in late-fall can be a good way to harvest late planted annual forage and avoid the challenges of making wet silage.
Yields Highly Variable
Yields of summer seeded cereals are highly variable, but under good conditions dry matter yields can typically be in the 1.25 – 1.75 tonne/acre range or more. In years of tight forage supplies, every bit counts. Cereals can be a good low-cost emergency forage option if timely rainfall is received for germination and growth.
Forage Nutrient Quality
A common question is “what is the forage quality of these summer seeded forages?” This depends entirely on:
1. maturity at harvest, as well as
2. acceptable moisture levels for successful fermentation.
Cereals harvested at flag-leaf or boot-stage will be higher nutrient quality, but lower yielding than cereals harvested at late-head or soft-dough stage. When peas have been added to cereals, nutrient quality can be very high. Some analysis of oat-pea forage mixtures has exceeded good quality alfalfa haylage.
Stage of maturity for optimum forage quality is at the “boot-stage” (head beginning to emerge from leaf whirl). Harvested at the boot-stage, fall grown oats are highly digestible and palatable. With cooler temperatures and shorter days, fall grown oats often have higher digestible energy than spring seeded oats. Boot-stage oatlage is excellent feed for dairy heifers and beef cows, but may not be adequate to include in high producing dairy cow rations. At the boot-stage, cereals are typically about 16.5% crude protein and 54% NDF with very good fibre digestibility. Once headed, nutritional quality declines rapidly. Harvesting at the headed or early-milk stages will provide more yield, but will have much lower digestible energy and protein. Wet chemistry rather than NIRS laboratory analysis of cereal forage is recommended.
There have been a few reports of high nitrate levels. When this is a concern, testing for nitrates is recommended, particularly if this forage makes up a high percentage of the diet. Refer to “Potential Nitrate Poisoning” http://fieldcropnews.com/?p=4976 .
Fall Rye, Winter Wheat or Winter Triticale?
If forage is needed next spring rather than this fall, winter cereals are an option. These winter-annual crops will out-yield summer seeded annual cereals harvested in the fall. They are usually planted in September or early-October after corn silage or early soybeans are harvested. Fall rye grown for silage can provide a significant amount of feed, but must be harvested at the correct stage of maturity for forage quality (flag-leaf to boot-stage). This will typically occur in early-May, and then another crop can be planted. (Double Cropping Fall Rye For Extra Forage http://fieldcropnews.com/?p=5241 ) Little research data exists for winter triticale grown as a forage in Ontario.
Other Forage Options
Wheat fields that had red clover underseeded as a cover crop are a good source of forage. Red clover makes excellent feed for high producing dairy cows. Refer to “Red Clover Haylage” http://fieldcropnews.com/?p=6605 . Summer seeded Italian ryegrass has also been used with good results, with excellent feed quality. Refer to “Annual Ryegrass For Stored Feed & Pasture” http://www.omafra.gov.on.ca/english/crops/facts/98-039.htm .
As the trend of high land costs and strong grain prices continues, and hay acreages continue to slip, many farmers are looking to summer seeded annual forages on a more regular basis as a method of producing additional forage in a double crop system.