Management tips for drought-stressed forages
The forage ‘To Do’ list……… • Monitor hay and pasture recovery and growth Assess general recovery & sod damage • Manage fertility inputs …. thoughtfully • Consider adding legume seed this spring to grass pastures • Consider overseeding additional or improved grasses on the ‘most damaged’, or ‘thinnest’ hay fields and pastures • Use ‘recovery mode’ in hay and grazing management
Next Sprin g………………………….. As an on-going management practice, Evaluate Hay field Stands for winterkill or winter injury ( This is not an exact science !) Alfalfa - at ‘green -up ’ or 2- 4 “ of spring regrowth • Get an ‘overall view of recovery’ • Check a 1 sq ft site per 5 - 10 A - count plants / sq ft Age of Stand Good Marginal Expect reduced yield ----------plants per square foot ------- Fall of seeding yr 20+ 10-20 < 10 Yr after seeding 12+ 8-12 <8 2 8+ 5-6 <6 3 6+ 4-5 <4 4 & older 4+ 3-4 <3
Dig all plants in the square foot ……… -- Count plants again ! -- Assess the general condition of plant crowns & taproots Healthy taproots are creamy-white and firm in texture Determine what % of taproots exhibit crown rot, and the degree of crown rot. http://www.ipm.iastate.edu/ipm/icm/1997/4-28-1997/evalalfalfa.html
Assess Taproot ‘Health’ Normal Minor Crown Moderate Poor Near-Dead Damage Crown Condition Plant Damage 1 2 3 4 5 If half or more are in categories ‘4’ or ‘5 ….. reduce your ‘plant counts per sq ft by half.
Next Spring………………………….. Evaluate pasture stands Walk your pastures when they begin to ‘green up’ -- both good and bad areas Visually determine % of soil covered with desirable forage vegetation Use a ‘better than’ or ‘thinner than’ about 70% cover as an assessment guide.
About 70% Cover
About 30% cover
About 50% Cover
About 80% Cover
If you have about 70% ground cover or greater …. And …….. If fall management and recovery was …….“ Normal” … good fall rainfall good residual leaf area going into winter Plan for “ normal “ spring pasture management - fertilize - manage your grazing - manage weeds
Fertilize pastures in the spring ……….. Phosphorus ( P ) and/or Potassium ( K ) IF they are needed; based on soil testing !! Nitrogen 40 ? 60 ? 80 ? lbs /Ac will stimulate spring growth * * [ N use efficiency is greater if P & K are adequate ] and * If there is sufficient spring soil moisture for good nitrogen response !
If fall recovery was……. Not favorable in fall 2012 … … limited fall rainfall … pastures grazed close and/or grazed late into the season and Pasture stand density is about 70% ground cover or greater Grass plant may still be under some physiological stress. Fertilize pastures in the spring ……….. Phosphorus ( P ) and/or Potassium ( K ) IF they are needed ; based on a soil test !! Nitrogen 40 ? 60 ? 80 ? lbs /Ac will stimulate spring growth * * [ N use efficiency is greater if P & K are adequate ] and * If there is sufficient spring soil moisture for good nitrogen response !
Give recovering pasture stands time to regain ‘vigor’. Pasture plants will benefit from allowing a bit more recovery and growing time in the spring before they are grazed. For best ‘recovery management’ ……. --- allow 3 - 4 “ of growth in the spring before livestock turnout And --- consider reducing stocking rates by 20 t0 30%
If you pasture stand density is Less than about 70% ground cover !! …. - consider oversowing or re-seeding Don’t’ fertilize with nitrogen (it will just add to the competition from the existing sod !) Keep the existing species Frost seeding But- competition from the sod, Interseeding less potential for erosion or No competition from a No-till renovation dead sod, low potential erosion
Frost seeding ( See ISU Ext Pub Pm-865 ) Goal: establish a partial new stand while maintaining the existing sod. Simple – broadcast seed on pasture in late winter or very early spring – when the ground is still frozen, may have some snow
Seed on the soil surface is covered by the soil movement during freezing / thawing cycles of late winter and very early spring [ late Feb to early March in Iowa ] Early spring rains also provide some seed covering in bare areas Frostseeding is less successful in dry springs !!!!! Less freeze/thaw coverage in dry soils , & less ‘spring rain coverage !!!
Inoculated legumes are most successful for frostseeding, Red, alsike, ladino clover better than alfalfa & trefoil Grasses - less success with frost seeding …… Orchardgrass > timothy > tall fescue > bromegrass
Best success on sites with exposed bare areas …… in bunchgrass sod (orchardgrass) or into thin sod areas in sod-forming grasses (Kentucky bluegrass, smooth bromegrass) More success when the pasture has been grazed very short ( less competitive !)
Other considerations with Frostseeding……… • Frequent (but not continuous ! ) grazing early during the seeding year … reduces sod competition • Avoid grazing on wet ground --- surface damage • Graze only on well established sod, do not want to destroy young sod
Several important steps that make frost seeding more consistently successful. ----------------------------------------------------- Weeds should be under control - broadleaf herbicides will kill new legume seedlings ! Fertility – is it good enough for legumes ? Grass sod should be short (less competitive) Moderate, periodic grazing after the pasture sod starts to grow in the spring ….. You want to provide sunlight to new, establishing seedlings !
Interseeding (ISU Ext Pub Pm-1097) : Goal: establish a partial new stand while maintaining the existing sod. • Seeding time March through April • Using drill to place the seeds • Similar success with legumes and grasses • But !!! Need more sod suppression with spring interseeding …… the pasture grasses have already begun to regrow !!!
Reduce sod competition ! -- Graze existing sod, in spring, if not already short – Continue to graze, rotationally, after interseeding, with grazing height above the new seedlings Or use ‘Chemical’ suppression ? • contact herbicide, Gramoxone Extra (paraquat) is labeled for this; Follow herbicide label instructions, and any grazing restrictions !! • sod must be actively growing for effective contact herbicide use • periodically graze after interseeding, with grazing height above the new seedlings … you want to provide sunlight to new, establishing seedlings !
Some considerations when using ‘chemical suppression’; When you remove grass competition, annual grassy and broadleaf weeds become more competitive. And !!! Suppression herbicides will eliminate much of your ‘spring flush’ of grass !!!!! Factor in the loss of grazing time & forage.
Sod-Seed or Inter-seed Use no-till pasture drill to seed into existing pasture sod in early spring (March and April) No-till drills provide: A disk-type or A seed metering A press wheel other sod/ & placement to provide seedbed mechanism seed-to soil contact opener with depth control
Sod-Seed or Inter-seed - continued As with frost seeding, some management practices improve interseeding success Weeds should be under control --- broadleaf herbicides will kill new legume seedlings ! Fertility – good enough for legumes ? Grass sod should be short Consider sod suppression herbicides Seed depth of ¼ to ½ in. with good seed to soil contact Drill inoculated legume seed Graze rotationally in the seeding year to allow sunlight availability to establishing seedlings.
No-till renovation (ISU Ext Pub Pm-1097) • Goal ? Reseed new plant species in killed sod or crop residue of previous grain crop • Chemical, (glyphosate; Round-Up) burn-down may be needed – For existing old sod fields, you need to wait until you have ~4- 6” of grass growth for the glyphosate to be most effective ….. this leads to relatively late spring planting – Don’t delay too long; it is harder to establish seedlings if hot and dry late-spring conditions develop • Use similar seeding rates as interseeding • Use similar no-till drill practices as when interseeding
Some other related ISU Ext Publications Pm-1792. Selecting Forage Species http://www.extension.iastate.edu/Publications/PM1792.pdf Pm-865 Improving Pasture by Frost Seeding http://www.extension.iastate.edu/Publications/PM856.pdf Pm-1097 Interseeding and No-till Pasture Renovation http://www.extension.iastate.edu/Publications/PM1097.pdf
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