Posts Tagged ‘forages’

Emergency Forages for Feed

Friday, June 10th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

With the very hot weather upon us and many areas of the state very short of available soil water, it is time to think about possible emergency forages for those producers with livestock. The traditional cool-season pasture and hay grasses such as orchardgrass, timothy, and tall fescue are not very productive during the summer months when high temperatures and drought limit their productivity and quality. On the other hand, the warm-season grasses do not reach their maximum growth rates until daytime temperatures rise into the 90°F. Summer annual grasses such as forage sorghum, sudangrass, sorghum-sudangrass hybrids, pearl millet, and teff can provide high quality summer grazing and sometimes emergency hay for livestock in our region. Many of these species even germinate when soil moisture conditions seem to be too dry for successful establishment although it often is difficult to know for certain if they will germinate and establish in a given situation. Although late planting limits their yield potential, many of these grasses can be planted up until late July and still produce valuable and needed animal feed although the cost of production will make the feed expensive.

The term “millet” is loosely used to refer to a variety of grass crops whose seeds can be harvested for human or animal feed. The term is used differently depending on local customs and sometimes continental influences. For example in many parts of Asia and Africa, sorghums are called millet whereas in Australia the species called broomcorn in the U.S. is called broom millet. When compared with the more commonly grown cereal grains such as corn, wheat, barley, and milo (grain sorghum), the millets are generally suited to less fertile soils and areas of drought or excess heat.

Foxtail, Italian, or German Millet
Foxtail millet can be planted when it is too late in the season to make most other crops. It takes about 65 to 70 days to mature with summer temperatures and enough moisture to establish the crop. The crop requires warm to hot weather and matures quickly under warm conditions. It has a low water requirement although it can’t stand severe drought since it is characterized by a shallow root system. This annual grass forms slender, erect but leafy stems that vary in height from 1 to 5 feet. Foxtail millet usually won’t regrow following a harvest, unlike pearl millet. It’s been used in our region for a single harvest hay crop. Millets should be planted about two weeks after ideal corn planting time. Millets also have smaller stems and tend to be leafier than the forage sorghums, sudangrass, and sorghum-sudangrass crosses.

The primary use for foxtail millet hay is for sheep and cattle. This grass can cause problems if used as a major part of a horse’s diet so as hay it should not be sold as horse hay. Problems include a laxative effect, excessive urination (cystitis), and kidney and bone or joint problems. The chemical, glucoside setaria, is found in foxtail and proso millet and is reported to cause illness and even death in horses. Foxtail or German millet also can cause oral mechanical lesions.

Pearl Millet
Pearl millet is considered the most suitable millet species for horse grazing or hay. It has moderate to good nutritional quality if kept short (about 2.5 feet or less). Pearl millet is leafy, with an upright growth habit, and grows from 4 to 8 feet tall. There are dwarf or semidwarf types such as Tifleaf I, II, and III that are leafier and have less stem than the taller types. Although the taller types produce more dry matter than the dwarf types, the stems make hay making more difficult. Although still requiring a mower-conditioner to crush the stems to hasten drying, the newer and leafier pearl millets are far superior to the older tall-type pearl millets. Pearl millet is more tolerant of lower pH and low fertility than the sorghum species.

Pearl millet does not contain glucoside setaria as does foxtail or proso millet and unlike the sorghums does not have the potential to cause prussic-acid (HCN) poisoning in animals. If raising pearl millet to feed horses, do not allow it to go to seed since a fungus can infect the seed and causes an accumulation of a toxic alkaloid (similar to alfatoxins in corn). Since pearl millet should not be harvested for hay when seeds are present (due to the very low quality of the forage), alkaloid toxicity should not be of concern to horse hay buyers.

Japanese Millet
Also called barnyard millet or billion dollar grass, Japanese millet is grown principally as a forage grass. It resembles barnyardgrass and probably originated from that species. It makes the most rapid growth of all the millets when conditions are favorable and can ripen grain in as little as 45 days. It should be cut for hay before heading to be palatable and to make curing easier since the plant can have thick stems. Usually it is from 2 to 4 feet tall and does best on the better soils.

Teff
Teff is the common name for an annual lovegrass that is primarily used for grain in Africa and Europe but is also used for hay in South Africa and parts of Europe. It has excellent seedling vigor and good production and quality traits although it is somewhat shallow rooted so there is concern about grazing animals (especially horses) pulling it out of the soil. A couple of reports from this region suggest that it can be successfully grazed by horses if seeded in an existing pasture.

It has been grown as a summer annual on Delmarva and has been sold here as grass horse hay. Teff’s palatability and quality vary greatly perhaps due to our lack of experience as to when to harvest the crop. As a hay crop, it can be cut and windrowed at early head (flower or seed head) emergence but you should not wait until the head is completely emerged and flowering has occurred since quality and palatability will be very much reduced.

Sorghum, Sudangrass, Sorghum-Sudangrass Crosses
For sorghum, sudangrass, sorghum-sudangrass crosses, hybrid sorghums, and other sorghum species, horses should not be allowed to graze and should not be fed hay from these species. Forage cystitis, an inflammation of the bladder can result. Sorghum species also contain prussic acid that can be metabolized or converted into cyanide. Cyanide poisoning can cause muscle weakness, urinary tract failure, neural degeneration, and death. This generally happens if the sorghum is grazed when young immature growth is present (plant height under 18 to 24 inches or regrowth occurs following a period of stress conditions or regrowth occurs during a grazing cycle) or the crop is damaged by frost or freezing weather. After a frost or freeze and until the foliage dries out (about 1 week), it should not be grazed. Regrowth after a frost or non-killing freeze should not be grazed.

It is very important to consider not only the expected yield potential from the many species and varieties of sorghum but also the digestibility of the varieties. Some BMR (brown mid-rib) sorghum varieties are now available and these have been shown to differ in daily average gains by as much as 0.75 lb/day. This difference in quality can translate to huge differences in the cost of producing a pound of beef. Many companies tout the high yield potential for the various sorghums and millets and may show yields in the 6 to 7 tons/acre range. In excellent production years (plenty of heat and rainfall), these yields can be achieved but in drought years a more realistic yield expectation of 2 to 3 tons/acre (using the entire summer growing season) should be the basis of your decision. Dr. Chris Teutsch at Virginia Tech’s Southern Piedmont AREC has conducted yield trials on many of these varieties so when making decisions refer to his results.

Kleingrass is also not recommended for horse since it produces a condition known as photosensitization. This is similar to that seen with alsike clover where sensitive horses can become severely sunburned.

Other Potential Problems
Nitrate toxicity following heavy nitrogen applications can occur especially during periods of summer drought. If urea or ammonium-based fertilizers are applied to the crop, it is only a matter of time before the nitrogen fertilizer is converted by soil bacteria into the nitrate form. After nitrate is taken up by the plant, stress conditions such as dry weather can lead to the accumulation of nitrate in the lower stems of grass plants. Stress conditions include not only drought but also cloudy, cool weather following the rapid uptake of nitrates since both situations prevent the plant from transforming the accumulated nitrate into amines, amino acids, and proteins. This is generally slightly less of a concern with horses than with ruminants but nitrate levels can be in high enough concentrations that a potential toxicity problems can occur in horses.

Some species of millet can cause problems when grazed as lush pastures because they can contain significant levels of oxalates. The oxalates interfere with calcium absorption and horses can develop bone malformation and lameness. To date, this problem has primarily been seen in Australia and not in the U.S.

 

Will Roundup Ready® Alfalfa Be Back?

Friday, July 9th, 2010

It appears that with a Supreme Court ruling a few weeks ago that Roundup Ready® alfalfa will eventually be available for planting. The questions that remain include not only when will this occur but what restrictions will be imposed on planting the crop and in what sections of the country it will be allowed. If you haven’t had a chance to read some of the articles that expound on the Supreme Court’s ruling, please take the time to look them up and read them over. It seems that both sides are able to claim victory from the ruling so it probably means that there will still be a number of months ahead of us before final rules are set in place so that in some areas and under some conditions, we can return to using this new technology. Monsanto has stated that they believe that plantings will be possible this fall while others doubt that this timeline can be achieved. If you’re interested in the technology and for growers who like to grow pure alfalfa hay or who like the ease of a single herbicide for most weed control, keep in touch with the latest developments in this story to know when it will be permissible to plant Roundup Ready alfalfa again.

Consider Temporary Annual Forage Crops for Fields to be Planted Later this Year

Friday, June 4th, 2010

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

If you were one of those producers whose pasture or hay field replanting was prevented by this past spring’s cold rainy weather, now is the time to consider a method of preparing the field for late-summer/early-fall (LS/EF) reseeding. The beginning of June’s hot weather (warm soil conditions) is ideal for seeding warm-season annual, weed-suppressing grasses such as hybrid pearl millet, sudangrass, the sorghum-sudangrass hybrids, or even teff. These grasses, if seeded when soil temperatures are >75° F and adequate soil moisture is present, can germinate and establish very rapidly. They have the ability to suppress many weed species and can add organic matter to the soil via the root mass left at the end of the season or the root mass plus final top growth of the season.

Another advantage of the warm-season annual grasses comes from the need for land preparation prior to the permanent LS/EF seeding. This soil preparation provides the producer with the opportunity to check the pasture or hay field’s soil fertility status and to make early adjustments that can be rechecked prior to planting the more expensive perennial grass seed. As an agronomist, I typically recommend checking six months to a year ahead of reseeding a field so that pH adjustment (liming) and nutrient amendments (phosphorus, potassium, or manures) can be applied and will have time to correct any problems in the field. Although the timing here may be tight, it still will allow a producer to recheck the field before establishing the permanent cover.

Another obvious benefit is the increased tonnage the summer annuals offer forage producers. However, care must be taken in selecting not only the annual grass species but the animal species that the forage will feed. Summer annual grasses can have a number of limitations/problems that can be successfully managed by the knowledgeable producer.

Common to all the species (even the cool-season grasses) is the potential for nitrate accumulation and nitrate toxicity during drought or cloudy weather when nitrates are not metabolized rapidly enough by the plant into proteins and amino acids. Nitrates taken up from the soil then accumulate, especially in the lower stems, and can reach toxic levels and are not reduced during hay harvest. Cyanide toxicity issues exist for sudangrass and the sorghum-sudangrass hybrids but this can be managed with grazing or cutting height. Sorghum species and species such as foxtail millet (Setaria spp.) can be harmful to horses (cystitis problems to name one concern). Hybrid pearl millet and pearl millet do not cause these problems and are generally considered safe for horses. Most of the species also have thick stems and large leaves that make hay making a bit more challenging. With careful management, the benefits from weed suppression, forage production, soil tilth, and early soil fertility adjustment out-weigh other concerns.

Spring Forage Plantings

Thursday, April 22nd, 2010

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

If you haven’t been able to finish planting pasture and hay fields with a cool-season grass (CSG) or CSG pasture mix by now, your best shot at having a successful seeding will be to wait until late summer or early fall to plant the new field. As a temporary measure, you can choose one of the annual warm-season grasses (WSG) such as sudangrass, a sorghum-sudangrass hybrid, teff, pearl millet or pearl millet hybrid, or even one of the new forage crabgrasses to plant in the field and produce feed for grazing or hay until you are ready to plant late this summer. Crops like sudangrass or the sorghum-sudangrass hybrids are very good smother crops and will help coke out weeds and result in a cleaner seedbed later this year.

Other suggestions to consider for new spring forage plantings include waiting until you have 2 to 4 inches of top growth on the forage grass seedlings and then topdressing with about 20 to 30 pounds of nitrogen per acre. Application of nitrogen at this point will stimulate grass growth and will tend to benefit the grass that, by this time, has established a fibrous root system capable of taking up nitrogen more efficiently than the tap-rooted broadleaf weeds. Stimulating early growth of the grass seedlings will help them compete against weeds and will help establish a larger root system while soils are still cool so the grass has a better chance of surviving periods of dry weather and heat as summer begins.

If you find that the new seeding has a lot of weeds that are ahead of the grass seedlings, try clipping or mowing the area to be sure that enough sunlight reaches the grass. You may need to continue this activity for several months and especially later in the year when the weeds begin to flower and mature seed. Mowing will at least reduce the amount of weed seeds returned to the soil weed seed bank.

Finally if the new seeding is for grazing, do not start grazing too early. If you have the land resource available, use the new seeding for at least one hay crop before changing it back to support grazing animals. This helps the grass become better established with larger root systems so that the animals do not pull new plants out of the soil. Also, keep the grazing pressure light during the first year, allowing the pasture regrowth to get 10 to 12 inches tall before beginning grazing and remove animals before they graze the pasture closer than 4 to 6 inches. The use of temporary fencing to do intensive rotational grazing is very helpful in managing new pastures and ensuring a vigorous healthy stand.

Weed Management in Summer Annual Grass Crops

Thursday, April 22nd, 2010

Quintin Johnson, Extension Associate, Weed Science; quintin@udel.edu and Richard Taylor, Extension Agronomist; rtaylor@udel.edu

The use of summer annual grasses for supplemental forage is gaining popularity. The advantage of the summer annual grasses is that they produce abundant forage during July and August, the period when cool-season grasses decline in productivity called the “summer slump”. When planted in late May or June, these grasses establish quickly, grow rapidly, have moderate to high drought tolerance, and can typically be grazed within 5 to 8 weeks of planting.

There are both common and species dependent disadvantages to the summer annual grasses. Common to all species is the fact that they usually are killed by the fall frost and will not survive the first fall freeze. The average date of the first fall frost is mid- to late-October for much of the region. By this time, cool-season grass production has increased again with the onset on cooler temperatures and fall precipitation levels. So although the death of the warm-season summer annuals can be considered a disadvantage, it is not a serious problem since pasture productivity usually has recovered by the time these summer grasses die.

Another common disadvantage is the extra production costs entailed with using annual species. The seed must be purchased each year, equipment must be rented or kept on hand to plant the annuals, and some form of annual tillage and/or vegetation control must occur. Seed costs, however, are relative and a review of many warm-season grass species as of the date of this article shows that seed costs range from $0.50 to $1.25 per pound and suggested seeding rates generally between 20 and 50 lb/acre. At a 30 lb/acre seeding rate and $0.75 per pound seed costs, annual seed cost would be under $25/acre contrasted with a novel-endophyte tall fescue which would cost about $150/acre but would be a long-term investment. Another mitigating factor to the cost issue is that many growers own or have access to brillion seeders that are old enough not to be considered a large capital expense. Annual tillage or seedbed preparation and the opportunity cost associated with the land area used for the annual crop will be the biggest expenses for summer annuals versus perennial cool-season grasses.

With certain precautions outlined below, cattle can graze or be fed forage sorghum, sudangrass, sorghum-sudan hybrids, foxtail millet, hybrid pearl millet, or crabgrass. Horses can graze hybrid pearl millet or crabgrass, and teff can be used for hay then grazed before frost.

Sorghum, sudangrass, and sorghum-sudangrass hybrids contain dhurrin which can break down and release prussic acid (HCN, cyanogenic compounds). Levels can be high enough in young, drought-stressed, wilted, injured, or frosted plants to cause cyanide poisoning. Millets do not contain dhurrin or prussic acid. The concentration of dhurrin varies by species with the most in sorghums and the least in sudangrass. Grazers should not graze these species if they are less than 18 inches tall and should delay grazing until young or re-growing plants are 24 to 30 inches tall. Do not graze drought-stressed plants until they recover after sufficient rainfall (usually 4 – 5 days) or until the plants fully recover from other stresses. Frosted plants should not be grazed until the leaves are dead and completely dried down, usually about a week to ten days following a killing frost. Cyanide dissipates from properly cured hay and properly ensiled forage, making them safe to feed.

All summer annual grasses can accumulate high levels of nitrates when fertilization is followed by stress (usually drought). The potential for nitrate poisoning can be reduced by moderating nitrogen fertilizer rates, allowing stressed plants to fully recover, testing for nitrate levels before grazing, and providing supplemental low-nitrate forage when moderate to high nitrate levels are suspected. Nitrate levels are not reduced in cured hay or green chopped forage, and are only partially reduced in ensiled forage. Another management option if the nitrate levels are not excessively high is to graze the tops of the forage and leave all the lower stubble. Nitrates are highest in the stem material and are highest closest to the soil surface. If harvesting fertilized drought-stress warm-season grasses for hay, avoid harvesting the lower stems. Millet accumulates as much or more nitrate than the sorghums. Horses have been observed grazing entire hybrid pearl millet plants to within an inch or two of the soil surface, so top grazing may not work in this situation.

Weed management begins with a clean seedbed. For conventionally tilled seedbeds, tillage should occur as close to planting as possible. In no-tillage seedings, follow the label concerning how much time to allow between the use of a nonselective herbicide such as glyphosate and seeding. When possible, choose fields with few to no perennial weeds, and avoid fields with a high number of grassy weeds.

As with any cool-season forage crop, successful establishment begins with properly amended soils (pH and fertility), proper seeding rate and depth, and appropriate seeding equipment. A critical component for establishment is waiting until the soil temperature warms enough to ensure rapid seedling emergence from the seedbed. When moisture is adequate, summer annual forage grasses emerge quickly, grow fast, and compete well with weeds. There often is no need for additional weed control. However, chemical weed control can be warranted when establishment is slow, weed populations are high, potentially toxic weeds are present, or high quality (weed-free) hay or forage is desired.

Unfortunately, herbicide options for summer annual grasses are limited. Some plant growth regulator (PGR) herbicides are labeled for use with these annual forages. Another limitation is that PGR herbicides are not recommended during the hot summer months due to their potential to injure sensitive plants with physical or vapor drift. Non-PGR herbicide options are listed in the table below. Pay particular attention to rotational crop restrictions for the preemergence herbicides (refer to label for crops not listed). Atrazine is typically not recommended due to its long rotation to other forage crops, and should only be used if corn or sorghum will be planted in the following spring. Check herbicide labels for weeds controlled. The postemergence herbicides in this table typically control only small annual broadleaf weeds. The herbicide labels will list the maximum weed size or growth stage at which the herbicide will be effective. Often the best herbicide is that weed-free seedbed and a rapid vigorous seedling. 

Table 1. Herbicide options for weed control in summer annual grasses

Herbicide Labeled annual grasses Timing/ weed type Application Information Grazing/ harvest interval Rotation Restrictions (months)
Use rate/acre Crop stage Season maximum rate To grasses To small grains To alfalfa/ clover
Atrazinea 4L Forage sorghum, sorghum × sudangrass hybrid PPI, Pre, POST/ broadleaf 3.2 to 4.0 pt (see label for details) Up to 12 inches 5 pt PPI or Pre = 60 daysPOST = 45 days Second year Next year to second yeare Second year
Callistoa Pearl millet Pre/ broadleaf Up to 6.0 fl oz n/a 6.0 fl oz(1 applic.) n/a 18 4 10/18
Dual II Magnumb,c Forage sorghum Pre/ grass 1.0 to 1.67 ptd n/a 1 applic. n/a Next spring 4.5 4/9
Aima Teff, crabgrass POST/ broadleaf 0.5 to 2.0 fl oz Any 5.9 fl oz(3 applic.) 0 0 0 12/12
Aima Millets POST/ broadleaf 0.5 to 2.0 fl oz Up to jointing 2.0 fl oz 7 days 0 0 12/12
Aima Forage sorghum POST/ broadleaf 0.5 to 1.0 fl oz Up to 6 leaf 1 fl oz After 6 leaf 0 0 12/12
Basagrana Forage sorghum POST/ broadleaf 1.0 to 2.0 pt Before heading 2 pt 12 days 0 0 0
Buctrilb 2EC (for 4EC formu-lation cut rates in half) Forage sorghum, sudangrass, sorghum × sudangrass hybrid POST/ broadleaf 1 pt 3 leaf but prior to pre-boot 2 pt 45 days 1 1 1
1.5 pt 4 leaf but prior to pre-boot

a Check label for adjuvant recommendations.

bNo adjuvant is recommended.

cRequires the use of Concep-treated seed.

dCoarase soils 1.0 to 1.33 pt/acre, medium soils 1.33 to 1.5 pt/acre, and fined soils 1.33 to 1.67 pt/acre.

eNext year if applied before June 10 or the second year after application if applied after June 10.

Caution on Distinct or Overdrive for Spring Treatment of Grass Forages

Thursday, April 22nd, 2010

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

UD Weed Research Program has seen significant leaf burn and stunting from use of Distinct or Overdrive on Timothy or Orchardgrass when applied in the spring during periods of rapid growth. Caution should be used with using Distinct or Overdrive prior to first cutting. Applications later in the summer appear to have greater safety on these species.

Weed Control in Forages

Thursday, March 25th, 2010

Quintin Johnson, Extension Associate – Weed Science; quintin@udel.edu and Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

If you have not done so yet, be sure to examine your hay, pasture, and alfalfa fields for weed infestations. Earlier applications are much more effective than later, as weeds get larger and start to produce seeds. For grass hayfields or pastures, weed control options include dicamba (Banvel or Clarity), 2,4-D, Overdrive, Crossbow, or Cimarron Max. Metsulfuron (active ingredient in Cimarron Max and Cimarron Ultra) and Crossbow provide residual control, while the other products do not. Be sure to read the label and follow all precautions concerning grazing and haying restrictions as well as overseeding and re-seeding restrictions. Remember that grasses seeded last fall should be tillering, actively growing, and mowed at least once before applications of dicamba or 2,4-D can be made.

Weed Control in Forages

Friday, April 10th, 2009

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

If you have not done so yet, be sure to examine your hay, pasture, and alfalfa fields for weed infestations. Earlier applications are much more effective than later as weeds get larger and start to produce seeds. For grass hayfields or pastures, weed control options include dicamba (Banvel or Clarity), 2,4-D, Overdrive, Crossbow, or Cimarron. Cimarron and Crossbow provide residual control, while the other products do not. Be sure to read the label and follow all precautions concerning grazing and haying restrictions as well as overseeding and re-seeding restrictions.

For pure alfalfa fields, Buctril, 2,4-DB, Pursuit or Raptor are labeled for broadleaf weeds. Pursuit and Raptor will provide both postemergence control as well as residual control. Select and Poast are labeled for grass control in a pure alfalfa stand. Recently Prowl H2O and Chateau have received labels for use in alfalfa. Both will provide residual control; be sure to read the labels and observe all precautions on application timing.

Teff Planting Date Approaches

Friday, May 16th, 2008

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

A number of growers have been asking about when they can plant the new grass hay crop, teff (Eragrostis tef). Teff is an annual warm-season grass and therefore similar to the other annual warm-season grasses in the need to hold off planting until the soil temperature at a two or three inch depth remains consistently above 65°F and actually is expected to rise soon into the 70°F range. In Delaware, this generally occurs in the third or fourth week of May. Recent rains and cool weather has dropped soil temperatures. This frequently happens throughout early and mid-May. Planting too early will delay germination and sometimes results in poor weedy stands.

Growers in Delaware and the Eastern Shore of Maryland have found that teff can be planted as late as the third week of June and will still allow growers to obtain several harvests. Keep in mind that once the temperatures begin to fall into the low forties in September or early October, teff growth will slow way down. The crop is quite frost sensitive and will generally be killed by the first frost in the fall.

A seeding rate of 4 to 8 pounds per acre of pelleted seed will be adequate to obtain a good grass stand. You should be sure that the seedbed is weed-free initially since the small seedlings are not very competitive although they become very competitive by four to six weeks post emergence. It is recommended that you apply about 50 to 75 lbs nitrogen (N) per acre at planting to carry the crop through the first harvest. Another application or two of N sometimes is needed to boost second and third harvest yields as well as maintain protein levels in the hay. Do not cut teff too close to the soil surface as it will need 3 to 4 inches of stubble to regenerate the stand.

Another important consideration in planting teff is seeding depth. Teff has a very small seed (1.25 million seeds per pound); and if planted much more than one quarter of an inch deep, the grass will have difficulty emerging, especially on some of our soils that tend to crust after a pounding rainstorm. In seedings where significant trash (crop residue) has remained on the soil surface, germination occurred best where there was the least residue, indicating the need for good soil to seed contact. Always firm up the seedbed both prior to planting and after the seed has been placed and covered in the seedbed. This will speed up germination and result in a better stand.

Forage analyses of teff hay have been variable, but generally lower than many growers have expected. Growers should keep in mind that teff is a warm-season grass and warm-season grasses, in general, have lower forage quality than the cool-season grasses. To help boost quality, teff should be cut for hay shortly after the seed heads begin to emerge from the boot and before it reaches full heading.

Update on Hay and Pasture Crop Irrigation

Friday, April 18th, 2008

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

Many of our hay and pasture species are just beginning the rapid growth phase that occurs each spring. More and more hay and pasture fields are set up to receive irrigation. The limited rainfall the southern half of the state has received so far this spring means that the soil water supply will be rapidly depleted as the cool-season hay and pasture grasses enter the rapid growth phase. Orchardgrass, in particular, since it matures earlier than many of the other species we grow, will be using large quantities of water during the next few weeks. If you are set up to irrigate hay and pasture fields, now is the time to begin the irrigation system. Try not to let the soil moisture levels be lowered to the point that water stress symptoms actually show up on the crop. As the species enter the rapid growth phase of spring, water use will increase from about a tenth of an inch of water per day to a quarter inch or more water per day. To keep fields actively growing, be sure to replace that quantity of water each week. When warmer temperatures occur in June, water use can increase to that approaching corn (about a third of an inch per day) so your irrigation regime will need to increase as summer approaches. Keep in mind that you will need to stop irrigation long enough for the soil to dry enough to support haying and baling equipment without causing significant compaction. It’s also usually best to wait until the crop begins regrowth before resuming irrigation so that you do not encourage weeds.

It also is time to get nitrogen (N) out on irrigated and non-irrigated hay and pasture fields. For hay, the latest research from Pennsylvania State University and Dr. Marvin Hall’s team shows that you should be applying about 50 lbs of N per acre per ton of expected yield. This is a good compromise between maximum economic yield from the hay and the risk of high nitrate levels in the hay if the crop becomes very drought stressed. For pastures, our N recommendations still vary based on the amount of legume in the pasture. If pastures contain a one to one ratio of legume to grass (50 percent of the biomass-forage-comes from the legume), additional N fertilizer will not be needed. If the legume component makes up between 25 and 50 percent of the forage, then apply about 25 lbs N/acre and if there is less than 25 percent legume in the forage, you may need as much as 50 lbs N/acre to maximize productivity of the pasture.