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Annual crops can provide for rest and recovery of perennial pastures from grazing or crop stress. They can be used to provide additional feed in years when you need it, such as during or after a drought, or they can become a routine part of your feeding strategy to give you added feeding flexibility. As part of your annual pasture rotation plan, annuals allow you to utilize more of your farm for grazing.
Because an annual crop can be grazed four to six weeks after spring seeding, and fall-seeded winter cereals can be grazed as early as mid-May, you can consider your selection of annuals based on when you need them (see growth chart below). Remember, for every day you delay grazing of your perennial pastures in the spring, you can gain three additional grazing days in the fall. Even if seeding is delayed, you can begin the grazing season on a perennial pasture, and move to an annual pasture when it’s ready. The perennial pasture will still profit from the rest.
Although not a cheap feed source, if you cut annual cereals as green feed they can provide better quality than perennial hay – especially if the crop is cut when heads are half full, for maximum energy value. Annual cereals are also an excellent source of silage. Not only will annuals help you get maximum returns from your perennial pastures, they can help you extend your grazing season – either in early spring or in late fall.
The most low-risk options for Manitoba growing conditions are winter and spring cereals, although there are many other options. Even though barley and annual rye have shown to be slightly higher in total digestible nutrients (TDN), your decision should be based on agronomic characteristics. Before you select a crop, review the agronomic data, keeping in mind your specific growing conditions, when you want to utilize the crop, and how you will harvest it (grazing, silage or green feed). The table on the following page is a good starting point.
Feed quality is similar between all cereals when they are utilized for grazing, and any minor difference can be managed with harvesting strategies. As indicated, your selection should be based mainly on the crop suitability to your growing conditions, and when you wish to harvest.
Barley and oats are good choices for early spring grazing because of their early growth habit, yield, palatability and grazing re-growth. Recent one-year trials in Roblin (Manitoba) showed barley to yield an average of 2.5 tonnes/ acre dry matter (DM), and oats an average of 3 tonnes/acre DM. However, caution must be taken with spring cereals so that grazing does not occur below the growing points. Otherwise, re-growth will be significantly reduced.
Since winter cereals require an over-wintering period to initiate seed head production (the process that brings the growing point above ground), spring-seeded winter cereals often have better re-growth and thus provide better grazing and hay yields in the year of seeding. However, the trade-off is that spring-seeded winter cereals are usually ready for grazing after the spring cereals. Fall seeding winter wheat, it should be noted, may provide a “green bridge” or food source for the wheat curl mite, the insect responsible for spreading wheat streak mosaic in later-emerging, spring wheat crops. Of the winter cereals, fall rye is usually more winter hardy than winter wheat and winter triticale, with a higher yield; however, yield is dependent on growing conditions.
Table 1. Selection Data for Annual Forages
Optimum Seeding Date
|Seeding Deadline||Seeding Rate Kg/Ha||Seeing Depth (cm)||Days to Emergence||Days to Maturity||When to Harvest|
|0ats||May 1 - Jun 20||Mid - Aug for fall grazing||90 - 115||4 - 7||10||100 - 103||Green feed-milk to early dough stage Grazing-pre-boot stage|
|Barley||May 1 - May 31||June 20||90 - 120||4 - 5||8||84 - 90||Green feed-early to mid-dough stage Grazing-pre-boot stage|
|Wheat||May 1 - May 31||June 20||100 - 135||3 - 8||10||99 - 105||Green feed-mid-dough stage Grazing-pre-boot stage|
|Winter Wheat (Spring Seeded)||May 1 - May 31||Mid - June||100 - 135||3 - 8||10||Next Season||Grazing-15-20 cm|
|Winter Wheat (Fall Seeded)||Aug 1 - Sept 15||Sept. 15||100 - 135||3 - 8||10||99 - 105||Fall grazing-15-20 cm Spring grazing- pre-boot stage Green feed-early dough|
|Triticale||Apr 15 - May 15||June 1||110 - 150||5||10||104 - 108||Green feed-dough|
|Spring Rye||May 1 - May 31||June 20||45 - 95||2.5 - 5||12||80||Green feed-early dough|
|Fall Rye (Spring Seeded)||May 1- May 31||Mid - June||45 - 95||2.5 - 5||12||Next Season||Grazing-15-20 cm|
|Fall Rye (Fall Seeded)||Aug 1- Sep 15||Sept. 15||45 - 95||2.5 - 5||10||88 - 104||Fall grazing-15-20 cm Spring grazing-pre-boot stage Green feed - early dough stage|
|Corn||May 1 - May 25||June 10||55,000 - 70,000||2.5 - 5||5 - 10||100 - 115||Silage-65-70% moisture Grazing-late fall-early winter|
|Turnips||May 1 - June 25||June 5||4.5 - 9||1.5 - 1.8||5 - 10||Graze-tops @ 60-75cm Re-graze-tops and bulbs, late fall|
|Peas||May 1 - May 25||June 10||130 - 200||5 - 8||8||89 - 93||Silage|
|Siberian Millet||May 25 - Jul 10||July 15||20 - 25||1 - 2.5||10||60 - 90||Silage-early heading|
|Proso Millet||May 15 - July 10||July 15||25 - 35||1 - 2.5||10||85 - 90||Silage-early heading to bloom stage|
|Sorghum||May 15 - Jun 1||June 5||6 - 8||2.5 - 35||10||Silage-mid-dough|
|Sorghum Sudan Hybrids||May 26 - Jun 16||July 5||20 - 30||1 - 2.5||10||Swath grazing-60-70 cm (cut early) Green feed-dough stage|
|Italian Ryegrass (Pasture Type)||Apr 10 - Jun 1||June 5||20||Less than 2||6 - 10||40 - 60||Grazing-6-8" Hay-early flowering, 5-6 wks after seeding|
|Westerwold Ryegrass (Hay Type)||Apr 10 - Jun 1||June 5||20||Less than 2||6 - 10||40 - 60||Grazing-6-8" or boot stage|
For silage, barley and oats often provide better feed quality than other spring cereals. If you’re using winter cereals, plant in the fall rather than the spring because plants need to overwinter to produce seed heads. Seed heads provide more energy, protein and yield in silage. Stages for cutting annuals to be used as silage are typically similar to green feed (see Selection chart), but crops are not allowed to dry down as much. Consult your ag rep or forage specialist to learn more about silage.
There are a wide variety of annual crops that can be utilized for green feed, and most are harvested at the soft dough stage, when adequate levels of energy and protein will provide maximum yields. Since the growing point is well above ground at this harvest stage, re-growth is often compromised, especially if post-harvest moisture is not available.
One method of reducing feeding costs is to maximize the yield of your annual forage. Cutting annuals for silage, rather than for green feed, usually results in more nutrients being harvested because harvesting losses are lower. Since yields of annual forages in grazing regimes rely on re-growth, their yields are often further compromised due to the difficulty in managing grazing height. Grazing height must be kept above the growing point, which can only be accomplished by managing stock density and adequate rest periods for re-growth.
Annual crops can accumulate nitrates more than perennial crops – especially if they have received high levels of nitrogen fertilizer or are stressed due to drought or cold temperatures. If nitrate levels are high enough, animals can suffer from nitrite poisoning, so it’s important to test your crop before allowing animals to graze or before cutting it for green feed. Your ag rep office can perform a quick test to tell you if nitrates are present, but for a reading on the specific amount, you will have to send a sample to a feed lab.
Avoid grazing or cutting the crop during and shortly after high stress periods — for example, immediately after a rainfall if it has been dry for a few consecutive weeks. This delay in harvesting will allow the accumulation of nitrates to dissipate as crop growth resumes. If you have cut a crop for green feed but you’re concerned about nitrates, ensiling it is a good way to reduce them.
Intercropping is the practice of combining a spring cereal (e.g. oats) with a winter annual (e.g. fall rye) for season-long benefits. Intercropping has been shown to produce overall more dry matter than each crop on its own because of the constant productivity all season long. The spring cereal begins growth early in the season, shutting down towards the later part, while the winter cereal remains active and produces until late in the fall.
Intercropping also gives you the option of harvesting the spring cereal for silage, leaving the winter cereal below for mid to late-season grazing. If more silage or an early grazing season is preferred, seed the spring cereal more heavily, taking care not to seed so much that it restricts growth of the winter cereal underneath. If more later season grazing is needed, then seed the winter cereal at a slightly heavier rate.
Barley and fall rye make a good intercropping combination. Spring seed both crops at approximately 3/4 the normal seeding rate to provide even growth throughout the season.
Annual crop fertility is just as important for grazing, green feed, and silage crops as it is for grain production. Fertilize spring and winter cereals according to soil fertility tests, but because spring-seeded winter cereals grow more evenly throughout the summer, split applications of nitrogen are recommended. This will maintain good fertility conditions throughout the growing season and reduce the risk of high levels of nitrate accumulation in the plant. Applications of phosphate, potassium, and sulfur may also be necessary; potassium is especially beneficial for overwintering of fall-seeded cereals.
Studies show that grasshoppers prefer wheat over oats, and oats over barley. For chemical control of grasshoppers, consult your Guide to Crop Protection published by Manitoba Agriculture, Food and Rural Initiatives. For biological control, Ecobran™ has proven to work well when it is spread in alternate strips approximately 100 feet wide; used this way, it’s economical as well as effective.
As the plant matures, yield and energy will increase until the dough stage. However, the plant also becomes more fibrous as it matures, with protein beginning to fall right after the boot stage. Higher yields can be maintained at the expense of protein, and vice-versa. But because protein is an inexpensive supplement if required, the most-often recommended harvest stage for green feed and silage crops is at or near the dough stage.
The same disease problems apply to cereals for forage production as cereals for grain crop production. Of most concern are the leaf diseases, which will reduce forage yield and quality. It is important to be aware of the potential for spreading the leaf streak mosiac virus in spring wheat when including winter wheat in your feeding strategy. For more information on control, consult your Guide to Crop Protection.
Just as perennial pastures benefit from rotational grazing, so can your annual pastures. Giving them a rest by grazing one week on, three weeks off, can maximize your yields (see below).
Courtesy of the Western Forage/Beef Development Group, based on research from G. Reimer and R. Gaudie, AAFRD
Yields increase significantly when grazing occurs one week out of the month, as opposed to every second week or every week.
Healthy pastures and riparian areas are better able to sequester carbon, and more-widely distributed manure reduces greenhouse gas emissions compared to manure packs. For more information on greenhouse gas, and how livestock producers can do their part to help reduce it, visit the following website.
This information is posted with permission. The following agencies worked collaboratively and provided funding support for this publication:
Partial funding for this publication was provided by the Greencover Canada Program, a five-year, $110-million Government of Canada initiative designed to help producers improve grassland-management practices, protect water quality, reduce greenhouse gas emissions, and enhance biodiversity and wildlife habitat.