There are 346,050 acres of Ohio farmland enrolled in the Conservation Reserve Program (CRP). As contracts approach their expiration date, participants are faced with the decision of what to do with the CRP acres. Many factors must be evaluated in making this decision. but anyone wishing to participate in other USDA programs must meet Conservation Compliance provisions. Agricultural commodities cannot be produced on highly erodible land (HEL) unless soil erosion prevention measures are initiated or installed that maintain soil loss to USDA acceptable standards. Maintaining CRP cover and using it for pasture or hay production would most likely meet the Conservation Compliance demands. Breaking out of CRP cover would necessitate in most cases installation of waterways or other measures such as residue management. These measures would probably need to be initiated prior to the actual planting of an agricultural commodity. Contact the Natural Resources Conservation Service (NRCS) for assistance in the decision of what to do with CRP acres as the contract nears its expiration date. If converting to pasture. fencing and water supplies may need to be developed. Your Ohio State University Extension county office and NRCS can be of assistance in the planning process. This factsheet outlines agronomic and weed control considerations in preparing CRP land for cropland or pasture/ hayland use.
The first step in concerting CRP land to cropland or pasture or hayland use is to take stock of the condition or the CRP cover. Consider the following
The condition of the forage stand will determine what steps need to be taken in converting CRP acres to cropland or for pasture and hayland use. The following are suggested management practices based on the general condition of the forage cover.
Fields that have been mowed annually may be suitable for no- till mulch-till, or conventional tillage production. The major concerns in these fields will be control of the grass or legume cover and any perennial weeds that are present. Fields that have not been mowed annually may have clumps of grass and brushy weeds that will make conservation tillage crop production difficult. Where necessary, consider plowing to make land more suitable for crop planting. If the land is highly erodible, consult with the NRCS prior to plowing. If the field is not plowed. regular mowing in the summer before a crop is planted will eliminate ground cover for rodents (mowing may also make it easier to plow).
No-till cropping into CRP acreage will be similar in some respects to no-till planting into sod. Careful planter adjustment and operation will be needed to ensure good seed placement and emergence in fields with uneven heavy residue cover. As with no-till crop production, heavy residue on the surface will lower soil temperatures and slow driving. It may be advisable to use row cleaners on planters, especially if residue is heavy or the field is not well drained. Where an early preplant herbicide has been applied, row cleaners should be set to move residue only with minimal soil disturbance. At least one significant rainfall event should occur between herbicide application and planting, to avoid moving herbicide with the residue where row cleaners are used. Delaying herbicide application and the killing of vegetative cover in the spring may help reduce soil moisture on poorly drained ground and improve crop emergence.
Choosing between corn and seybeans depends upon the field characteristics. Advantages of planting corn include: 1) corn can take advantage of available nitrogen (N); 2) using high rates of triazines in a field may help in bumdown of vegetation and control of annual broadleaf weeds: 3) using Banvel/Clarity, 2,4-D, Stinger, Accent, Beacon, or combinations of these herbicides can help in management of perennial broadleaf weeds; and 4) it is easier to apply soil insecticide using a corn planter compared to planting soybeans with a drill.
Advantages of planting soybeans: 1) planting can be delayed with less impact on yield, allowing more effective control of vegetative cover, and 2) postemergence grass herbicides can help manage perennial grasses that are not killed the previous fall.
Corn hybrids and soybean varieties that perform well under stress conditions would be good choices for some CRP ground. If corn planting is likely to be delayed, a short to mid season hybrid maturity may be most appropriate.
Conversion of CRP ground to corn or soybean production may lead to stand establishment problems due to the seedcorn maggot, grubs and wireworms commonly found in sod type environments. If corn is no-tilled into CRP ground, the risk for cutworm, stalk borer, and armyworm problems may also exist. Where com is planted into a sod type environment, use of a broad-spectrum soil insecticide at planting is recommended. If a soil insecticide is not applied at corn planting or if soybeans are planted into CRP ground. a seed treatment should be used. Tank-mixing insecticides with preplant or preemergence corn herbicides may reduce the risk of cutworm, stalk borer or armyworm in no-tillage plantings, but such treatments will have minimal effect on established wireworm or grub populations. Fields should be scouted after planting to detect potential pest problems.
Much of the CRP ground has been in grass sod for the past several years. Fertilizer recommendations based on soil samples from CRP acreage previously in sod may need to be adjusted downward to account for the contribution of various nutrients derived from the sod. Soil test levels of phosphorus (P) and potassium (K) are open very low in grassy, meadow-like fields (which have been characterized by long term sod growth). Following the hilling of vegetation with herbicides or tillage, the root and top growth will begin to decay and release P and K. These nutrients will likely be available to the crop after it is planted. As a result, little or no yield response can be expected from the use of P and K fertilizer the first year after sod, especially if there is a good, uniform sod cover and the P and K levels of the soil were not marginal when the field was initially placed into CRP. Therefore, fertilizer application during the first year probably should be based on likely crop removal rates, not by what is indicated for application in the soil test. Residual P and K from the killed sod will be largely depleted during the first year of crop production. Therefore, it is advisable to take another soil test at the end of the first vear so that the fertilizer needs can be established for the second year of cropping. The potential nitrogen (N) contribution from a good grass and a forage legume cover should also be considered. Up to 50 to 80 lbs of residual soil N/acre may be available when planting into grass/legume sods.
Fields that have not been mowed on a yearly basis may have a dense population of difficult to control perennial broadleaf weeds and brushy plants. Fields that have been mowed once or twice a year may still have a number of perennial broadleaf weeds, such as Canada thistle. These weeds are most effectively controlled when in the bud to bloom stage, or as late in the fall as possible before a hard freeze, when systemic herbicides such as Roundup, Banvel, and 2,4-D can move into the root system. If brushy weeds are present. including multiflora rose, spot-treat these in the late spring through early fall when actively growing and fully leafed out, or treat the previous winter with a basal bark dormant application. Multiflora rose is more easily controlled with early summer applications, while other brushy species mav be more easily controlled in the fall. Moldboard plowing helps considerably in the control of many perennial and brushy weeds, but must be carefully used in some fields. Where herbicides are foliar-applied in the fall, do not plow or disk for at least seven days after application.
Fall is also the best time to apply Roundup. Banvel, and/or 2,4-D to kill perennial grasses or legumes in the field. The field can be mowed once in early summer, but this should be done early enough in the summer to allow regrowth of perennial weeds and grass covers (no later than early July) Mowing prior to August 1 may require an exemption from the CFSA-check with your local office. Roundup is the best option to kill perennial grass covers, and grasses should be at least 12 inches tall and actively growing in the fall for best results. Otherwise. apply as late in the fall as possible before a hard freeze. For fall application, a Roundup rate of at least 1 1/2 quarts per acre may be necessary in some CRP fields due to the dense grass stand. Banvel and/or 2,4-D will usually provide good control of a legume cover, but will not control grasses. Roundup plus 2,4-D is effective for a mixed grass legume stand. The following spring, prior to crop planting, an application of Roundup, Banvel, and/or 2,4-D may be necessary to kill any remaining grass or legume cover, as well as other emerged weeds. Note: Applying these herbicides in the spring to achieve complete control of perennial weeds and grass or legume covers is not recommended. Perennial grasses and broadleaf weeds are extremely difficult to kill in the spring, and a herbicide application the previous fall is strongly recommended If herbicide is applied in the spnng to kill a grass cover that was not treated the previous fall, delay application until grasses are 8 inches tall, and apply at least 2 quarts/A of Roundup (plus 1 quart/A of 2,4-D if legumes are also present). Spring control of grasses will be most effective where the Roundup is followed with atrazine/Badex treatments in corn. Do not plant soybeans in a field where clover or alfalfa has not been completely killed, because legumes are not controlled by postemergence soybean herbicides.
Expect high populations of giant foxtail in fields that are converted from CRP to crop production. Increasing preplant or preemergence grass herbicide rates to the maximum allowed by the label for a soil type may improve control. A more effective approach to high foxtail populations is to use a postemergence herbicide to control grasses that escape preplant treatments. An economical approach to foxtail control in soybeans might include a preplant application of Prowl, Canopy, or Scepter to suppress or control grasses, followed by a postemergence herbicide such as Select, Assure, Fusion, or Poast Plus to control later emerging foxtail plants. Postemergence options for grass control in corn include Accent or the use of Poast Plus on one of the new SRC (sethoxydim-resistant) corn hybrids.
CRP acres have tremendous potential for being used in forage/livestock production If annual mowing has been practiced, thatch build-up is probably not severe. Such fields are likely to have fewer serious weed problems. Fields that have been mowed on a regular basis will be easier to convert into productive, high-quality forage stands than where mowing has not been practiced and forage growth is rank with large clumps, excessive thatch buildup, and difficult to control weeds are present.
Take a soil test to determine nutrient status of the soil coming out of CRP. As discussed above for row crops, phosphorus and potassium application during the first year of production should probably be based on likely crop removal rates. Each ton of tall grass or legume removes 13 pounds of P205 and 50 pounds of K2O. Forages may be topdressed with phosphorus and potassium at any time of the year. Soil conditions are frequently most conducive to fertilizer applications immediately after the burst cutting and/or in late summer or early fall. It is advisable to take another soil test at the end of the first cropping year to determine fertilizer needs for the second and subsequent productions years. Nutrients should cycle naturally in a well-managed pasture through nitrogen fixation from legumes (if present) and livestock excrement. The distribution of recycled nutrients through grazing animals is dramatically affected by grazing management. An assessment of uniformity of animal manuring across the pasture should be made before crediting the returned nutrients to the entire pasture acreage.
Nitrogen should be applied where legumes are less than 30% of the stand. Economic returns are usually obtained with 150 to 175 pounds of N per acre split three times during the year. Legumes can be interseeded or frost seeded into grass pastures to reduce or eliminate the need for fertilizer 09 applications.
If converting to hayland and problem weeds are present. follow the same guidelines provided previously relative to control of perennial and brushy weeds. Apply Banvel, 2,4-D, Stinger, Crossbow, or Ally depending upon the weeds present. These herbicides are labeled for grass stands. For stands where good densities of desirable legumes are present, the only herbicide option that will not eliminate them is Sencor/Lexone applied in late fall or early spring when plants are dormant. Roundup can also be applied as a spot treatment when plants are actively growing but will injure or kill the desirable grasses and legumes.
Managed grazing can effectively control many weed species, so a herbicide program may not be needed if converting to pasture use. However, if difficult to control perennial and brushy weeds are present, follow the same guidelines provided above.
Note: All Roundup rates are for fall application in 3 to 10 gallons of water per acre with 0.5% nonionic surfactant plus 17 lbs per acre of ammonium sulfate. Control of perennial grasses with spring herbicide applications alone is difficult and not recommended. Where a spring application is planned, apply at least 2 quarts/A of Roundup (plus 1 quart/A of 2,4-D if legumes are present) when grasses are more than 8 inches tall, and follow with atrazine/Bladex treatments in corn.
Bromegrass- Apply Roundup at 2 quarts per acre in the fall when grasses are actively growing and are at least 12 inches tall, or as late in the fall as possible before a hard freeze.
Orchardgrass- Where corn will be planted, apply Roundup at 1 to 1 1/2 quarts per acre in the fall when orchardgrass is at least 6 inches tall. Application of atrazine in the spring will be necessary for complete control. Where atrazine will not be used in the spring, apply Roundup at 2 quarts per acre in the fall when grasses are actively growing and are least 12 inches tall, oras late in the fall as possible before a hard freeze.
Tall fescue- Apply Roundup at 1 to 1 1/2 quarts per acre (higher rates for more dense grass stands) in the fall when plants are actively growing with 6 to 12 inches of new growth. A follow-up treatment in fall or spring of an additional 1 pint per acre may be necessary for complete control.
Timothy- Apply Roundup at 1 to 1 1/2 quarts per acre (higher rates for more dense grass stands) in the fall when timothy is actively growing and at least 12 inches tall, or as late in the fall as possible before a hard freeze.
Alfalfa- Allow regrowth of 6 to 8 inches following cutting before herbicide application. Apply one of the following treatments in the fall: Banvel (1/2 pint/A) + 2,4-D (1 pint/A); or Roundup (1 quart/A) + 2,4-D (1 pint/A): or Roundup (1 quart/A) + Banvel (1/2 pint/A).
Clover- More easily killed than alfalfa. A spring application of atrazine + Bladex or Extrazine II may be sufficient where corn will be planted. The addition of 2,4-D or Banvel/Clarity can improve control. Planting soybeans into a legume cover is not recommended. Any of the following treatments should be effective in the fall: 2,4-D ester (1 quart/A); or Banvel (1/2 pint/A) + 2,4-D (1 pint/A); or Roundup(1 quart/A) + 2,4-D (1 pint/A); or Roundup (1 quart/A) + Banvel (1/2 pint/A). Note: ladino clover is tolerant of 2,4-D, and will be more easily controlled with Banvel.
Blackberry (briars)- Apply Roundup at 3 to 4 quarts per acre or as a spot treatment (1.5% solution) in late summer or fall when plants are fully leafed out. Apply as long as stems are green or until a killing frost.
Canada thistle- Where a crop will be planted the next spring, apply Roundup at 1 quart per acre in the fall when thistles are in the bud to bloom stage, or as late in the fall as possible before a hard freeze. Avoid tank-mixing with 2,4-D or Banvel unless other weeds are present that require this treatment. The most effective treatments in grass pasture include: Stinger (2 1/3 to 1 1/3 pint/A) when thistles are at least 4 inches tall and before the bud stage; or a spot treatment of Roundup (2% solution) when thistles are in the bud to bloom stage. Ally, 2,4-D, Banvel, or Crossbow will suppress Canada thistle, and are less effective than the previously listed products. but can be effective in combination with intensive mowing.
Dandelion- 2,4-D is more effective than Roundup or Banvel. Apply one of the following treatments in the fall: 2,4-D ester (1 quart/A); or Banvel (1/2 pint/A) + 2,4-D (1 pint/A); or Roundup (1 quart/A) + 2,4-D (1 pint/A).
Multiflora rose- Foliar-applied herbicides are effective when applied to actively growing plants in late spring through early fall depending upon the product. Roundup (1% solution) or Ally (1/2 oz per 100 gallons) can be applied as a foliar spray in May through September. Crossbow (1.5% solution) or Banvel (1% solution) should be applied by the end of May for best results). Banvel can also be applied as a spot concentrate or Lo-oil basal bark treatment when rose is dormant, from late December through early April. See the label for more information on dormant applications.
Fall application of Roundup as a broadcast treatment (3 to 4 quarts per acre) or as a spot treannent (9% solution) will provide control of a number of perennial weeds. For more economical application, or to achieve control of weeds that are somewhat tolerant of Roundup, apply combinations of Roundup (1 qt/A) plus 2,4-D (1 pt/A to 1 qt/A) or Banvel (1/2 pint/A). Spot treatment with Crossbow may be more effective than Roundup on some brushy type species. Check labels for guidance on brushy weed control.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
TDD No. 800-589-8292 (Ohio only) or 614-292-1868