Management Strategies for Permanent Grass Pastures / CRP / Grass ...
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Management Strategies for Permanent Grass Pastures/CRP/Grass Hay Long-term management of weeds in pasture and CRP areas is necessary to maximize pasture productivity and the growth of desirable species established in CRP areas, control weeds that are poisonous to livestock, and to prevent the encroachment of weeds into adjacent crop production fields. Some weed species are considered noxious weeds under state law and must be controlled, or the landowner can be subject to fines. Many forage and grass species used in pastures and CRP have prolific growth characteristics and are effective at suppressing weeds. Effective establishment and maintenance of these species can greatly minimize weed problems. Factors in establishment include starting weed-free through tillage or the application of glyphosate or other non-selective herbicides, fertilization or liming as necessary based on soil testing, use of the proper seeding rate, and proper maintenance of over-grazed areas. Soil fertility should be periodically monitored and supplemented to maintain a healthy pasture or cover crop that is competitive with weeds. This should include testing the nitrogen level for grass species and pH for legume growth. Where phosphorous and potassium are at proper levels initially, these nutrients should cycle through the residue unless hay harvest is allowed. If the area is harvested for hay, then soil in the area may need to be tested, and nutrients applied to maintain further health of the pasture or CRP cover. Use grazing practices that prevent deterioration of desirable species, since weeds will rapidly infest areas devoid of a competitive stand of grasses and legumes. Weeds are controlled in pastures and CRP land primarily by mechanical or chemical methods. Mowing is a viable option, depending upon the species to be controlled. Mowing is more effective for control when it can be used several times in the same year. Custom rates for rotary mowing in recent years averaged about $13 per acre, with a range of $6 to $19, based on information from The Ohio State University and Purdue University.
The most effective herbicide application timing for perennial weed control is generally mid-September through late October depending upon the species. Herbicide effectiveness at that time will be maximized by applying after several days of warm weather when perennial weeds are fairly large and/or in the bud to flower stage. Perennial weeds should be at least 8 to 12 inches tall in order to obtain maximum control of the roots or rhizomes for next year. For warm-season perennials such as johnsongrass, hemp dogbane, milkweeds, common pokeweed, and bindweeds, applications in mid- to late September should provide the most effective control. This strategy can prove effective in controlling perennial weeds, which are not well controlled by mowing alone. Herbicides can effectively control many weeds in pastures and CRP, and can be a less expensive alternative to mowing. Herbicide effectiveness, similar to mowing, also varies by weed life cycle and timing of application. A primary disadvantage of herbicide application – most herbicides that can be used for control of broadleaf weeds in CRP will injure or kill desirable legumes in the cover. Exceptions to this are bromoxynil, Butyrac, and Plateau, which can be applied to mixed stands of grasses and legumes. These herbicides can be used to control weeds during CRP cover establishment, depending upon the species planted and herbicide. Herbicide selection should take into account the weed species, CRP cover species, application method, and the presence of water in nearby ditches. Most herbicides can be applied to dry ditchbanks, but only some dicamba, 2,4-D, and glyphosate products are labeled for application directly to water. See product labels for more information. CRP contracts are written with maintenance provisions that include the control of weeds through mowing or herbicides. The CRP contract usually limits mowing to a certain time of the year, so as“not to disturb the acreage under contract during the primary nesting and brood rearing seasons for wildlife except as approved by the CCC.” This limitation may reduce the overall effectiveness of mowing as a weed control method, especially for certain perennial species. CRP contracts may allow more
Grass Pastures
Annual weeds should be mowed prior to or soon after flowering to prevent the production of viable seed. Seed production may occur earlier than the timing of mowing allowed by CRP contracts. Biennial weeds have a two-year cycle. Emergence of plants from seed occurs in the first year, and the plants remain in the vegetative stage as a low-growing rosette with short internodes that grow close to the ground. Mowing is typically not effective for control of plants in this stage, because not enough leaf area can be removed to affect the plant growth. Elongation of the stem and development of a large plant occurs in the second year, as well as flowering and seed production. Mowing can be used in year two to control biennial plant growth and reduce seed production. Perennial weeds reproduce by both seed and plant parts such as stems, tubers and roots. Perennials should be mowed in the early bud stage. This is the point in the life cycle when carbohydrate movement from roots is at the lowest levels. Mowing at this time can help reduce the viability of the plant parts used to produce new plants and prevent seed production,
but mowing rarely controls perennials completely. The bottom line - mowing can be used to prevent seed production, and it can effective for weed control when used at plant growth stages when the plant is most vulnerable or least likely to regrow. A combination of mowing and herbicide applications may be most effective for the control of perennial weeds. Mowing in mid-summer removes weed growth from the first half of the season, and prevents seed production by many annuals and biennials. The initial growth of cool-season perennials is also removed, followed by their regrowth into the fall, when herbicides can be most effective. Mowing CRP areas before the first week of August will allow for maximum regrowth of perennial weeds. Applying herbicide in July or August will prevent seed production by annual weeds, but this is not the most effective timing for control of cool-season perennial weeds.
158 frequent mowing for control of noxious weeds such as Canada thistle. Weed management practices and the herbicides approved for use in CRP can vary between Ohio and Indiana, and also within a state. Landowners should consult contracts and local NRCS offices for more information on approved weed management practices (see below). Labels for some products specify application timing and rate based on the grasses that are being established or are present in a CRP area. This may include recommendations for cool-season vs warm-season grasses, which are categorized in the following table. The tolerance of many native forbs and grasses has not been characterized for some herbicides. Labels
for some products warn of this and state that the manufacturer is not responsible for injury to native forbs and grasses. See the following web sites for information on CRP contract requirements and management practices: Indiana - http://www.in.nrcs.usda.gov/programs/CRP/ crphomepage.html Ohio - http://www.nrcs.usda.gov/programs/crp/
Cool Season Grasses Annual Ryegrass (I)1 Bluegrass, Rough (I)
Warm Season Grasses Buffalo (N)
Bahia (N)
Bentgrass (I and N)
Canada wildrye (N)
Bermuda (I)
Eastern gramagrass (N)
Bluegrass, Kentucky (N)
Orchardgrass (I)
Big bluestem (N)
foxtail millet (I)
Perennial ryegrass (I)
Smooth brome (N)
Bluestem yellow
Indiangrass (N)
Tall fescue (I) Virginia wildrye (N)
timothy (I)
(caucasian)(I) Little bluestem (N)
Pearl millet (I) Swithgrass (N)
Broomsedge (N)
Grass Pastures
1I
= introduced species, N = Native species. CRP guidelines require the use of native species.
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. " !"' "%!""'%&& &'(%&"/
157
Management Strategies for Permanent Grass Pastures/CRP/Grass Hay Long-term management of weeds in pasture and CRP areas is necessary to maximize pasture productivity and the growth of desirable species established in CRP areas, control weeds that are poisonous to livestock, and to prevent the encroachment of weeds into adjacent crop production fields. Some weed species are considered noxious weeds under state law and must be controlled, or the landowner can be subject to fines. Many forage and grass species used in pastures and CRP have prolific growth characteristics and are effective at suppressing weeds. Effective establishment and maintenance of these species can greatly minimize weed problems. Factors in establishment include starting weed-free through tillage or the application of glyphosate or other non-selective herbicides, fertilization or liming as necessary based on soil testing, use of the proper seeding rate, and proper maintenance of over-grazed areas. Soil fertility should be periodically monitored and supplemented to maintain a healthy pasture or cover crop that is competitive with weeds. This should include testing the nitrogen level for grass species and pH for legume growth. Where phosphorous and potassium are at proper levels initially, these nutrients should cycle through the residue unless hay harvest is allowed. If the area is harvested for hay, then soil in the area may need to be tested, and nutrients applied to maintain further health of the pasture or CRP cover. Use grazing practices that prevent deterioration of desirable species, since weeds will rapidly infest areas devoid of a competitive stand of grasses and legumes. Weeds are controlled in pastures and CRP land primarily by mechanical or chemical methods. Mowing is a viable option, depending upon the species to be controlled. Mowing is more effective for control when it can be used several times in the same year. Custom rates for rotary mowing in recent years averaged about $13 per acre, with a range of $6 to $19, based on information from The Ohio State University and Purdue University.
The most effective herbicide application timing for perennial weed control is generally mid-September through late October depending upon the species. Herbicide effectiveness at that time will be maximized by applying after several days of warm weather when perennial weeds are fairly large and/or in the bud to flower stage. Perennial weeds should be at least 8 to 12 inches tall in order to obtain maximum control of the roots or rhizomes for next year. For warm-season perennials such as johnsongrass, hemp dogbane, milkweeds, common pokeweed, and bindweeds, applications in mid- to late September should provide the most effective control. This strategy can prove effective in controlling perennial weeds, which are not well controlled by mowing alone. Herbicides can effectively control many weeds in pastures and CRP, and can be a less expensive alternative to mowing. Herbicide effectiveness, similar to mowing, also varies by weed life cycle and timing of application. A primary disadvantage of herbicide application – most herbicides that can be used for control of broadleaf weeds in CRP will injure or kill desirable legumes in the cover. Exceptions to this are bromoxynil, Butyrac, and Plateau, which can be applied to mixed stands of grasses and legumes. These herbicides can be used to control weeds during CRP cover establishment, depending upon the species planted and herbicide. Herbicide selection should take into account the weed species, CRP cover species, application method, and the presence of water in nearby ditches. Most herbicides can be applied to dry ditchbanks, but only some dicamba, 2,4-D, and glyphosate products are labeled for application directly to water. See product labels for more information. CRP contracts are written with maintenance provisions that include the control of weeds through mowing or herbicides. The CRP contract usually limits mowing to a certain time of the year, so as“not to disturb the acreage under contract during the primary nesting and brood rearing seasons for wildlife except as approved by the CCC.” This limitation may reduce the overall effectiveness of mowing as a weed control method, especially for certain perennial species. CRP contracts may allow more
Grass Pastures
Annual weeds should be mowed prior to or soon after flowering to prevent the production of viable seed. Seed production may occur earlier than the timing of mowing allowed by CRP contracts. Biennial weeds have a two-year cycle. Emergence of plants from seed occurs in the first year, and the plants remain in the vegetative stage as a low-growing rosette with short internodes that grow close to the ground. Mowing is typically not effective for control of plants in this stage, because not enough leaf area can be removed to affect the plant growth. Elongation of the stem and development of a large plant occurs in the second year, as well as flowering and seed production. Mowing can be used in year two to control biennial plant growth and reduce seed production. Perennial weeds reproduce by both seed and plant parts such as stems, tubers and roots. Perennials should be mowed in the early bud stage. This is the point in the life cycle when carbohydrate movement from roots is at the lowest levels. Mowing at this time can help reduce the viability of the plant parts used to produce new plants and prevent seed production,
but mowing rarely controls perennials completely. The bottom line - mowing can be used to prevent seed production, and it can effective for weed control when used at plant growth stages when the plant is most vulnerable or least likely to regrow. A combination of mowing and herbicide applications may be most effective for the control of perennial weeds. Mowing in mid-summer removes weed growth from the first half of the season, and prevents seed production by many annuals and biennials. The initial growth of cool-season perennials is also removed, followed by their regrowth into the fall, when herbicides can be most effective. Mowing CRP areas before the first week of August will allow for maximum regrowth of perennial weeds. Applying herbicide in July or August will prevent seed production by annual weeds, but this is not the most effective timing for control of cool-season perennial weeds.
158 frequent mowing for control of noxious weeds such as Canada thistle. Weed management practices and the herbicides approved for use in CRP can vary between Ohio and Indiana, and also within a state. Landowners should consult contracts and local NRCS offices for more information on approved weed management practices (see below). Labels for some products specify application timing and rate based on the grasses that are being established or are present in a CRP area. This may include recommendations for cool-season vs warm-season grasses, which are categorized in the following table. The tolerance of many native forbs and grasses has not been characterized for some herbicides. Labels
for some products warn of this and state that the manufacturer is not responsible for injury to native forbs and grasses. See the following web sites for information on CRP contract requirements and management practices: Indiana - http://www.in.nrcs.usda.gov/programs/CRP/ crphomepage.html Ohio - http://www.nrcs.usda.gov/programs/crp/
Cool Season Grasses Annual Ryegrass (I)1 Bluegrass, Rough (I)
Warm Season Grasses Buffalo (N)
Bahia (N)
Bentgrass (I and N)
Canada wildrye (N)
Bermuda (I)
Eastern gramagrass (N)
Bluegrass, Kentucky (N)
Orchardgrass (I)
Big bluestem (N)
foxtail millet (I)
Perennial ryegrass (I)
Smooth brome (N)
Bluestem yellow
Indiangrass (N)
Tall fescue (I) Virginia wildrye (N)
timothy (I)
(caucasian)(I) Little bluestem (N)
Pearl millet (I) Swithgrass (N)
Broomsedge (N)
Grass Pastures
1I
= introduced species, N = Native species. CRP guidelines require the use of native species.
