alfalfa management guide—establishment (1 of 3)

NCR547 North Central Regional Extension Publication

management guide

Alfalfa

Published byASA, CSSA, and SSSA

All copyrights reserved 2004

AuthorsDan UndersanderExtension agronomist, forages University of Wisconsin

Roger BeckerExtension agronomist, weed controlUniversity of Minnesota

Dennis CosgroveExtension agronomist, foragesUniversity of Wisconsin

Eileen CullenExtension entomologistUniversity of Wisconsin

Jerry DollExtension agronomist, weed controlUniversity of Wisconsin

Craig GrauExtension plant pathologistUniversity of Wisconsin

Keith KellingExtension soils scientistUniversity of Wisconsin

Marlin E. RiceExtension entomologistIowa State University

Mike SchmittExtension soils scientistUniversity of Minnesota

Craig SheafferResearch agronomistUniversity of Minnesota

Glen ShewmakerExtension agronomistUniversity of Idaho

Mark SulcExtension agronomistThe Ohio State University

Alfalfa management guide



The authors wish to thank reviewersfrom industry and various univer-

sities for their suggestions and every-one who supplied photos, includingthose not specifically mentioned:

Steve Bicen, University of Wisconsinanthracnose; aphanomyces, roots; Fusarium wilt, roots; Phytophthora,roots; root assessment; verticillium wilt, root

Dennis Cosgrove, University of Wisconsinautotoxicity

Jim Ducy title page photoDel Gates, Kansas State University

alfalfa weevils Craig Grau, University of Wisconsin

aphanomyces, stunting; bacterial wilt, stunting; black stem, lesions; Fusariumwilt, field; Phytophthora, plant; sclerotinia; stand assessment; verticillium wilt, plants

B. Wolfgang Hoffmann, University ofWisconsin alfalfa plant, page 1; alfalfaflowers

Eric Holub, University of Wisconsinaphanomyces, seedling

Jeffrey S. Jacobsen, Montana StateUniversity nutrient deficiencies—allexcept boron leaf (from Diagnosis ofNutrient Deficiencies in Alfalfa andWheat)

Pioneer Hi-Bred International, Inc. alfalfa closeups; cover photo ; cow; inside cover

Lanie Rhodes, Ohio State University black stem, leaves; common leaf spot; lepto leaf spot

Marlin E. Rice, Iowa State University alfalfa weevil, blister beetles; clover leafweevils; grasshopper; pea aphids; plantbug, adults; potato leafhopper, adult; spittlebug; variegated cutworm

Judy A. Thies, USDA-ARS root-lesion nematodes

John Wedberg, University of Wisconsin alfalfa blotch leafminer; clover rootcurculio, damage

Thanks also to Bruce Gossen and RealMichaud, research scientists at Agricultureand Agri-Food Canada, for their contribu-tions to the disease maps.

This publication is a joint effort of:University of Wisconsin-Extension, Cooperative ExtensionMinnesota Extension Service, University of MinnesotaIowa State UniversityCooperative Extension Service

Editor: Linda DeithDesigner: Susan Anderson

Published by:American Society of Agronomy, Inc.Crop Science Society of America, Inc.Soil Science Society of America, Inc.© 2004 by the American Society of Agronomy,Inc., Crop Science Society of America, Inc.,and Soil Science Society of America, Inc.All rights reserved under the U.S. Copy-right Law of 1978 (P.L. 94-553)Any and all uses beyond the limitations ofthe “fair use” provision of the law requirewritten permission from the publishers; notapplicable to contributions prepared by offi-cers or employees of the U.S. Government aspart of their official duties.

Library of Congress CatalogCard Number 00 135829The views expressed in this publicationrepresent those of the individualauthors. These views do not necessarilyreflect endorsement by the publishers.In addition, trade names are sometimesmentioned in this publication. Noendorsement of these products isintended by the publishers, nor is anycriticism implied of similar products not mentioned.

Printed in the U.S.A.

A C K N O W L E D G M E N T S



Establishment . . . . . . . . . 2Select a field carefully . . . . . 3

Soil type, drainage, and slope . . 3Control perennial weeds . . . . . 3Autotoxicity . . . . . . . . . . . . 3

Test soil before planting . . . . 4Apply lime before seeding . . . . 6Nutrient needs during

establishment . . . . . . . . . . . 7Select a good variety . . . . . . 8

Yield potential . . . . . . . . . . . 8Persistence . . . . . . . . . . . . . 8Winterhardiness . . . . . . . . . . 9Fall dormancy . . . . . . . . . . . 9Disease resistance . . . . . . . . . 9Forage quality . . . . . . . . . . . 9Intended use . . . . . . . . . . . . 9

Planting. . . . . . . . . . . . . . . 10Time of seeding . . . . . . . . . . 10Field preparation . . . . . . . . . 11Seed inoculation . . . . . . . . . 12Seeding depth and rate. . . . . . 12Seeding with and without a

companion crop. . . . . . . . . 13Seeding equipment . . . . . . . . 14Reduced tillage and

no-till planting . . . . . . . . . 16

Production . . . . . . . . . . . 17Fertilize annually . . . . . . . . 18

Determine needs . . . . . . . . . 18Nitrogen . . . . . . . . . . . . . . 20Phosphate and potash . . . . . . 20Secondary nutrients . . . . . . . 21Micronutrients . . . . . . . . . . 21

Irrigation . . . . . . . . . . . . . . 22Manure management . . . . . . 23Weed management . . . . . . . 23

Weed management before planting . . . . . . . . . . . . . 23

Weed management in the seeding year . . . . . . . . . . . 23

Weed management in established alfalfa. . . . . . . . 26

Disease management . . . . . 28Anthracnose . . . . . . . . . . . . 28Aphanomyces root rot . . . . . . 29Bacterial wilt . . . . . . . . . . . 30Common leaf spot and

lepto leaf spot . . . . . . . . . . 31Fusarium wilt . . . . . . . . . . . 32Phytophthora root rot . . . . . . 33Root-lesion nematodes . . . . . . 34Sclerotinia . . . . . . . . . . . . . 35Spring black stem. . . . . . . . . 36Summer black stem. . . . . . . . 36Verticillium wilt. . . . . . . . . . 37

Insect management . . . . . . 38Alfalfa blotch leafminer . . . . . 38Alfalfa weevil . . . . . . . . . . . 38Aphids . . . . . . . . . . . . . . . 40Blister beetles . . . . . . . . . . . 40Clover leaf weevil . . . . . . . . 41Clover root curculio . . . . . . . 42Grasshoppers . . . . . . . . . . . 42Plant bugs . . . . . . . . . . . . . 43Potato leafhoppers . . . . . . . . 44Spittlebugs. . . . . . . . . . . . . 45Variegated cutworm . . . . . . . 45

When to rotate from alfalfa . . . . . . . . . . . . . . . 45

Harvest. . . . . . . . . . . . . . 47Forage quality . . . . . . . . . . 48

What quality forage is needed? . 48Plant growth and forage quality 49

Harvest management . . . . . 50Cutting schedule . . . . . . . . . 50

Fall management . . . . . . . . 51Hay and silage

management . . . . . . . . . . 53Feeding considerations of

hay and haylage . . . . . . . . 55

C O N T E N T S ________________________________________________________________________________________________________



Profitable forage production

depends on high yields. Land,

machinery, and most other oper-

ating costs stay the same

whether harvesting 3 tons per

acre or 6 tons per acre. Top

yields in the northern United

States have approached 10 tons

per acre while average yields

are around 3 tons per acre. This

booklet describes what it takes

to move from a 3-ton yield to

6 or 9 tons per acre.



A vigorously growing, dense

stand of alfalfa forms the basis

for profitable forage production.

Profitable stands are the result

of carefully selecting fields with

well-drained soil, adding lime

and nutrients if needed, select-

ing a good variety, and using

appropriate planting practices

to ensure germination and

establishment.

Establishment



Select a field carefullySoil type, drainage, andslope

A lfalfa requires a well-drained soilfor optimum production. Wet soils

create conditions suitable for diseasesthat may kill seedlings, reduce forageyield, and kill established plants. Youcan reduce some disease problemsassociated with poor drainage byselecting varieties with high levels ofresistance and by using fungicides forestablishment. Poor soil drainage alsoreduces the movement of soil oxygento roots. Poor surface drainage cancause soil crusting and pondingwhich may cause poor soil aeration,micronutrient toxicity, or ice damageover winter. Even sloping fields mayhave low spots where water stands,making it difficult to maintain alfalfastands.Soils should be deep enough to haveadequate water-holding capacity.Alfalfa has a long taproot that pene-trates more deeply into the soil thancrops such as corn or wheat whichhave more fibrous, shallow roots.Under favorable conditions, alfalfaroots may penetrate over 20 feet deep.This great rooting depth gives alfalfaexcellent drought tolerance.

Sloping fields where erosion is aproblem may require use of erosioncontrol practices such as planting witha companion crop or using reducedtillage to keep soil and seed in placeuntil seedlings are well rooted.

Control perennial weedsFields should be free of perennialweeds such as quackgrass. If notcontrolled before seeding, theseweeds may re-establish faster than thenew alfalfa seedlings and reducestand density. Weed management isdiscussed in more detail in theProduction section.Fields should be free from herbicidecarryover that may affect growth ofthe new alfalfa and/or companioncrop. This is especially important afterdrought years and on fields wherehigh herbicide application rates orlate-season applications of long-lasting herbicides were used.

AutotoxicityAlfalfa plants produce toxins that canreduce germination and growth ofnew alfalfa seedings. This phenome-non is known as autotoxicity. Theextent of the toxin’s influenceincreases with the age and density ofthe previous stand and the amount ofresidue incorporated prior to seeding.The autotoxic compounds are watersoluble and are concentrated mainlyin the leaves. The compounds impairdevelopment of the seedling tap rootby causing the root tips to swell andby reducing the number of root hairs(figure 1). This limits the ability of theseedling to take up water and nutri-ents and increases the plant’s suscep-tibility to other stress factors.

3_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

Figure 1. Effect of autotoxicity on rootdevelopment of alfalfa.

Source: Jennings, Nelson, and Coutts,Universities of Arkansas and Missouri, 1998

autotoxins present normal plants

To assure good stands, calibrate seeding depths and rates carefullyand plant in a firm, moist soil.



Surviving plants will be stunted andcontinue to yield less in subsequentyears (figure 2). A waiting period afterdestroying the old stand is necessaryto allow the toxic compounds todegrade or move out of the root zoneof the new seedlings. Weather condi-tions influence the speed with whichthe toxins are removed. Breakdown ismore rapid under warm, moist soilconditions. The autotoxic compoundsare removed more rapidly from sandythan more heavy textured soils.However, while the compounds arepresent, the effect on root growth ismuch more severe in sandy soils.Ideally, grow a different crop for oneseason after plowing down or chemi-cally killing a 2-year or older standbefore seeding alfalfa again in thesame field. This is the best and safestway to manage new seedings ofalfalfa.

Test soil beforeplanting

Proper fertility management, includ-ing an adequate liming program, is

the key to optimum economic yields.Proper fertilization of alfalfa allowsfor good stand establishment andpromotes early growth, increasesyield and quality, and improveswinterhardiness and stand persis-tence. Adequate fertility alsoimproves alfalfa’s ability to competewith weeds and strengthens diseaseand insect resistance.

4 ________________________________________________________________________ A L F A L F A M A N A G E M E N T G U I D E

Figure 2. Effect of waiting periods when establishing alfalfa follow-ing alfalfa. Note that even though the number of plants is similar forall but fields planted with no waiting, yield increases dramatically.

Source: Cosgrove et al., University of Wisconsin-River Falls, 1996

Effect of autotoxicity on alfalfa stands when alfalfais seeded (a) immediately following alfalfa plow-down, (b) 4 weeks later, and (c) after 1 year.

b

c

a

0 weeks 2 weeks 4 weeks fall-killed after corn

yie

ld (

% o

f che

ck v

arie

ty)

0

20

40

60

80

100plowedno-till

0 weeks 2 weeks 4 weeks fall-killed after corn

nu

mb

er

of

pla

nts

/ft2

0

10

20

30

40

50



Fields differ in their fertilizer needs.Soil testing is the most convenient andeconomical method of evaluating thefertility levels of a soil and accuratelyassessing nutrient requirements.Most soil testing programs makerecommendations for pH and lime,phosphorus, potassium, and severalof the secondary nutrients andmicronutrients. Optimal soil testlevels for alfalfa differ among statesdue to varying subsoil fertility, nutri-ent buffering capacities, soil yieldpotentials, and different managementassumptions. For more detailed infor-mation on soil test recommendations,contact your local Extension office.

5_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

Advanced techniquesReseeding recommendationsReseeding stands within 1 year carries acertain amount of risk of yield and stand failuredue to autotoxicity. Use table 1 to calculate therisk. If reseeding, consider the following:

n Disk down a seeding failure and reseedeither in the late summer after a springseeding or the following spring. Autotoxiccompounds are not present the first year.

n Reseed gaps in new seedings as soon aspossible.

n Never interseed to thicken a stand that is 2years old or older. Young plants that havebeen interseeded often look good early butdie out over summer because of competitionfor light and moisture from the establishedplants.

n In stands where the likelihood of success-fully interseeding alfalfa is low, considerinterseeding red clover or a grass speciessuch as ryegrass or orchardgrass. Thesespecies will most likely establish well andprovide good yield until new stands can bere-established.

Table 1. Alfalfa autotoxicity reseeding risk assessment

points score

1. Amout of previous alfalfa topgrowth incorporated or left on soil surfaceFall cut or grazed 10 to 1 ton topgrowth 3More than 1 ton topgrowth 5

2. Disease resistance of the variety to be seeded

High disease resistance 1Moderate disease resistance 2Low disease resistance 3

3. Irrigation or rainfall potential prior to reseeding

High (greater than 2 inches) 1Medium (1 to 2 inches) 2Low (less than 1 inch) 3

4. Soil typeSandy 1Loamy 2Clayey 3

5. Tillage prior to reseedingMoldboard plow 1Chisel plow 2No-till 3

6. Sum of points from questions 1–57. Age of previous alfalfa stand

Less than 1 year 01 to 2 years 0.5More than 2 years 1

8. Reseeding delay after alfalfa kill/plowdown12 months or more 06 months 12 to 4 weeks 2Less than 2 weeks 3

Your total score (multiply points from 6, 7, and 8)

Alfalfa reseeding riskIf you score: The autotoxicity risk is: Recommendation

0 low Seed

4 to 8 moderate Caution, potential yield loss

9 to 12 high Warning, yield loss likely

> 13 very high Avoid reseeding, likely stand & yield loss

Source: Craig Sheaffer, Dan Undersander, and Paul Peterson, Universities of Minnesota and Wisconsin, 2004.



Apply lime before seedingLiming is the single most importantfertility concern for establishing andmaintaining high yielding, highquality alfalfa stands. Benefits ofliming alfalfa include:

■ increased stand establishment andpersistence,

■ more activity of nitrogen-fixingRhizobium bacteria,

■ added calcium and magnesium,■ improved soil structure and tilth,■ increased availability of phospho-

rus and molybdenum (figure 3),and

■ decreased manganese, iron, andaluminum toxicity (figure 3).

For maximum returns, lime fields toat least pH 6.7 to 6.9. Field trialsperformed in southwestern Wisconsinshow that yields drop sharply whensoil pH falls below 6.7 (figure 4).

Because lime reacts very slowly withsoil acids, it should be applied 12months—preferably longer—beforeseeding. For typical 4- to 6-year croprotations, the best time to apply therecommended amount of lime is whencoming out of alfalfa. This allows timefor reaction with the soil. In addition,the accompanying tillage for rotationcrops may result in two or threeremixings of the lime with the soil. Bythe time alfalfa is replanted, the pHshould be raised to the desired level.Aglime should be broadcast on thesurface of the soil, disked in, and thenplowed under for maximum distribu-tion and neutralization of acids in theentire plow layer. Plowing withoutdisking may deposit the lime in alayer at the plow sole. For high ratesof lime (more than 6 tons/acre), applyhalf before working the field; workthe remaining half into the soil afterplowing or other field preparation.

Lime effectiveness is determined byits chemical purity and the fineness towhich it is ground. Figure 5 illustratesthe greater effectiveness of morefinely ground lime. To achieve thesame pH change, coarse aglime mustbe applied further in advance and athigher rates than fine aglime but isusually less expensive per ton. It maynot be necessary to re-lime as oftenwhere some coarse lime is used.When comparing prices, be sure toevaluate materials on the basis ofamounts of lime needed to achievesimilar effectiveness. The relativeeffectiveness of various liming materi-als is given by its lime grade, effectivecalcium carbonate equivalency (ECCE),effective neutralizing power (ENP), ortotal neutralizing power (TNP).


nitrogen

phosphorus

potassium

sulfur

calcium

magnesium

iron

manganese

boron

copper and zinc

molybdenum

4 5 6 108 97

acidic pH basic

Figure 3. Available nutrients in relation to pH.

0

1000

2000

3000

4000

5000

pH

dry

ma

tte

r yi

eld

(lb

/acr

e)

4.5 5.5 6.5 7.5

Figure 4. First-cutting alfalfa yield relative to soil pH.

Source: Wollenhaupt and Undersander, University of Wisconsin, 1991



Liming materials come in severalforms. Calcitic products containcalcium-based neutralizers whiledolomitic sources contain bothcalcium and magnesium. Both areeffective for changing soil pH. Someclaims are made that when thecalcium to magnesium ratios in thesoil are low, calcitic limestone shouldbe used. Research evidence does notsupport these claims, as virtually allmidwestern and northeastern soilshave ratios within the optimal range.Dolomitic limestone itself has acalcium to magnesium ratio withinthe normal range for plant growth.The addition of calcitic limestone orgypsum for the purpose of addingcalcium or changing the calcium tomagnesium ratio is neither recom-mended nor cost effective.Several by-products, such as paper-mill lime sludge and water treatmentplant sludge may be used as limingmaterials. Since the relative effective-ness of some of these materials ishighly variable, be sure you know itseffective neutralizing power.

Nutrient needs duringestablishmentTillage during establishment providesthe last opportunity to incorporaterelatively immobile nutrients duringthe life of the stand. Typical nutrientadditions tend to include phosphorus,potassium, and sulfur.Phosphorus. Adequate soil phospho-rus levels increase seeding success byencouraging root growth. Phosphorusis very immobile in most soils. Wiscon-sin research confirms that at low tomedium soil test levels, incorporatedphosphorus is more than twice as effi-cient as topdressed phosphorus.Potassium. Research has shown thatalthough potassium has relativelylittle influence on improving standestablishment, yield and standsurvival are highly dependent on anadequate potassium supply. Whensoil tests are in the medium range orbelow, sufficient potassium should beadded to meet the needs of theseeding year crop including thecompanion crop.

Sulfur. Elemental sulfur, whereneeded, can be used as the sulfursource and may be applied at seeding.Elemental sulfur must be converted tosulfate-sulfur before it can be used byplants. This process is relatively slow,especially when sulfur is topdressed.Therefore, incorporating moderatelyhigh rates (50 lb/acre sulfur) ofelemental sulfur at establishment willusually satisfy alfalfa sulfur require-ments for the life of the stand. Despitethe higher cost, sulfur is typicallytopdressed annually with fertilizerrather than incorporated at plantingdue to ease of application.Nitrogen. Research has shown thatsmall additions of nitrogen mayenhance establishment and seedingyear yields. Apply 25 to 30 lb/acrenitrogen when alfalfa is direct seededon coarse-textured soils with loworganic matter contents (less than2%). Apply 20 to 35 lb/acre nitrogenwhen seeding alfalfa with a compan-ion crop and apply 40 to 55 lb/acrenitrogen if you will be harvesting thecompanion crop as silage.Manure. Manure is a source ofmacronutrients and micronutrientsand can be used to help meet thenutrient needs of alfalfa. Manuretesting is recommended prior toapplication to any cropland.For application before seeding,manure should be thoroughly mixedwith the soil and limited to rates ofnot more than 7 tons/acre of soliddairy manure or 20,000 gal/acre ofliquid dairy manure (environmentalrequirements may lower the recom-mended rates).

7_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

20

40

60

80

100

aglime particle size (mesh)

% n

eu

tra

lizi

ng

eff

ec

t in

3 y

ea

rs

0>8 8–20 20–60 <60

Figure 5. Lime availability at different particle sizes.



Select a goodvariety

Plant breeders have developedalfalfa varieties with greater yield

potential, better disease resistance,and improved forage quality. But withover 250 varieties available, how doesone decide? The major factors leadingto profitability are:

n yield potential, n persistence (percent stand remain-

ing or estimated from winterhar-diness and disease resistanceratings),

n winterhardiness, n disease resistance, and n forage quality.

As illustrated in table 2, yield has thelargest effect on profitability, persis-tence next, and other factors have alesser effect. Other factors such as falldormancy and intended use may beimportant in certain circumstances.

Yield potentialLook for varieties with high yields inuniversity trials. Compare new vari-eties against one you have grown.Comparing varieties to the samecheck, planted within the trial, alsoallows comparison across severaltrials. New varieties should performbetter and result in higher yields. InWisconsin and Minnesota varietytrials performed between 1980 and1998, the top varieties have yieldedslightly over 1 ton more per acre thanVernal (a standard check variety) foreach year of stand life (figure 6). Forshort-term stands, select varieties byyield from 2- to 3-year-old stands. Forlong-term stands, select by yield from4- to 5-year-old stands.Varieties will perform differently invarious growing regions. Look for topyields of a variety grown in a site withas similar a soil type and climate toyour farm as possible. Also, look fortop yield over several sites. This indi-cates stability for high yield and isimportant because soils may vary onyour farm and weather conditionschange from year to year.

PersistenceCompare stand survival ratings oryields of 4- to 5-year-old stands todetermine relative persistence of vari-eties. Persistence in northern locationsdepends primarily on winterhardi-ness because of the severity of wintertemperatures; farther south persis-tence is more dependent on diseaseresistance. If stand survival ratings oryields of 4- to 5-year-old stands arenot available, use winterhardinessand disease resistance to estimatepersistence.When evaluating varieties, rememberthat long-term stands are not neces-sarily the most profitable. Manyfarmers are finding that a 4-year rota-tion with 3 years of alfalfa may bemore profitable than trying to keepone stand of alfalfa for 5 or 6 years ina 7- or 8-year rotation. This occurs forthe following reasons:

n younger stands of alfalfa yieldmore than older stands,

n with a 4-year rotation, nitrogencredits from plowdown alfalfa areavailable twice in 8 years,


0

age of stand (years)

1 2 3 4

yie

ld in

cre

ase

(to

ns/a

cre)

5

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Arlington, WI Rosemount, MN

Source: Undersander and Martin, Universities of Wisconsin and Minnesota, 1998

Source: Undersander, University of Wisconsin, 1991Abbreviations: ADF = acid detergent fiber; CP = crude protein; NDF = neutral detergent fiber.

Figure 6. Yield increase over Vernal of top five vari-eties in Wisconsin and Minnesota from 1980 to 1998.

Table 2. Factors influencing dollar return peracre for alfalfa from milk production.

returnfactors per acrestandard yield $778

(18% CP, 33% ADF, 45% NDF)assuming 5 ton/acre yield and $10/cwt milk

yield potential –$500.2 ton/acre lower yield

persistence –$24shorter stand life (3 vs 4 yr)

forage quality +$15higher quality forage(+1% CP, –1% ADF, –1% NDF)

seed cost –$4$1/lb higher at 15 lb/acre seed



n corn following alfalfa yieldsapproximately 10% more thancorn following corn, and

n corn rootworm is less of aproblem in the first year followingalfalfa than in corn following corn.

WinterhardinessWinterhardiness is a measure of thealfalfa plant’s ability to survive thewinter without injury. It is measuredon a scale of 1 to 6 with 1 being themost hardy and 6 being the leasthardy (see figure 7). Winter-injuredplants may survive the winter, but thebuds formed in the fall for springregrowth may be killed. Such plantshave fewer shoots for first cutting andproduce a lower yield.

Fall dormancyFall dormancy is measured by deter-mining how tall alfalfa grows in themonth following a September 1cutting. More dormant types, such asVernal, will remain short and lowyielding through the fall period nomatter how good the growing condi-tions are. Less-dormant varieties typi-cally yield more in the fall, green upearlier in the spring, and recover morequickly between cuttings. Plant breeders have finally broken therelationship between winterhardinessand fall dormancy. Until recently,obtaining higher yields meant select-ing a variety with less dormancy andlower winterhardiness. The strategynow should be to choose less-dormant varieties that meet yourwinter survival requirement. Theseplants will green up earlier in thespring and recover more quicklybetween cuttings to give higher totalseason yields.

Disease resistanceDiseases may kill seedlings, reducestand density, lower yields, andshorten stand life. The best diseasemanagement strategy is to select vari-eties with high levels of disease resis-tance. Determine potential fordiseases on your farm and selectalfalfa varieties with resistance to asmany of them as possible. Knowingwhich diseases have occurred in yourfields will help you choose varietieswith the appropriate resistance. Lookover the descriptions and pictures inthe disease section of this booklet,learn to recognize them, and selectresistant varieties if the disease isoccurring in your field. To estimatethe potential for each disease to occurin your area, refer to the maps in thedisease management section.

Forage qualityMany new varieties coming on themarket have improved forage quality.Evaluate alfalfa varieties based onestimated digestibility, intake, andrelative feed value compared toVernal, the standard variety.

Intended useMost alfalfa is planted for harvest ashay or haylage with plans to keep

stands as long as they areproductive. Special situa-tions may require differ-ent variety selection crite-ria. For example, when ashort rotation is desiredor when nitrogen forother crops is needed,yield is more importantthan persistence so selectvarieties with high yieldsin the first 2 years. Whenthe field will be used forgrazing, select grazing-tolerant varieties.

9_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

The two plants on right show severe winter injury. Damagedplants are slow to regrow and produce few stems.

12

4

5

6

3

Figure 7. Winterhardiness needed. Varieties grown north of primary region ofadaptation will suffer winterkill and injury.Western mountain valleys may grow lesswinterhardy varieties than indicated.



PlantingTime of seedingSpring seeding is preferred over late-summer seeding in northern statesdue to a greater chance of successfulstand establishment. Better growingconditions, such as a longer growingseason, adequate soil moisture, andcool temperatures, enhance seedgermination and establishment. Late-summer seeding is preferred in south-ern states because of the opportunityto establish alfalfa after growinganother crop. Herbicides are notgenerally required for late-summerseeding. Irrigation allows late-summer seedings in all areas.

Spring seeding of alfalfa can begin assoon as the potential for damage fromspring frosts has passed. At emer-gence, alfalfa is extremely cold toler-ant. At the second trifoliate leaf stage(figure 8), seedlings become moresusceptible to cold injury and may bekilled by 4 or more hours at 26°F orlower temperatures. Alfalfa seededwith a companion crop surviveslower temperatures and longer expo-sure times before showing frostdamage. Frost damage is usually not aproblem by the time fields are tilledand ready to seed. Spring seedingshave less weed competition and lessmoisture stress during germinationthan do late-summer seedingsbecause of cooler temperatures. The spring seeding dates shown onthe map (figure 9) are averages for theregion. Seeding may be earlier onlight soils, when a companion crop isused, or when forages are establishedusing reduced-tillage or no-tillmethods. Irrigation may extend theseeding period later into the spring.Although successful stand establish-ment can be made outside the recom-mended dates, the likelihood ofconsistent success is low.

Successful late-summer seedingdepends on soil moisture during theestablishment period and sufficientplant growth before a killing frost(figure 9). Do not seed unless goodsoil moisture is present. A preplantherbicide is usually not needed forlight weed infestations becauseannual weeds will be killed by frost.Postemergence herbicides can be usedif severe weed pressure or volunteergrain problems develop. Use of acompanion crop is not recommended,especially if seeding before August 15,because it will compete with alfalfafor moisture. In many regions, Sclero-tinia crown rot may be prevalent inlate-summer seeding.Alfalfa needs at least 6 weeks growthafter germination to survive thewinter. The plant will generallysurvive if it develops a crown before akilling frost. The crown allows theplant to store root reserves for wintersurvival and spring regrowth. Fieldswith less seedling development beforea killing frost may have a greaterproblem with winter annual weeds,particularly in southern areas.


Figure 8. Alfalfa seedling development.

Source: Dodds and Meyer, North Dakota State University, 1984

first leaf,unifoliate

second leaf, trifoliate

hypocotyl

cotyledonepicotyl

15–30 days10–15 days0–10 days



Minimizing competition from volun-teer small grains or weeds is critical innorthern regions to ensure adequatedevelopment of summer-seededalfalfa prior to killing frost. Failure todo so cuts seedling establishment andlowers yields (figure 10), particularlyin no-till fields.

Field preparationField preparation should begin theyear before seeding. Perennial weedscan be particularly competitive bothduring the seeding year and in subse-quent years. Controlling weeds beforeseeding will help ensure a long-lasting, productive stand. Scout fieldsfor perennial weeds and use appropri-ate control measures. For example, ifquackgrass is in a field where cornwill be planted, use a pretillage appli-cation of glyphosate or a postemer-gence application of Accent orBeacon. Cultivate when corn is 14 to18 inches tall. Similarly, controlCanada thistle, yellow nutsedge,dandelion, and other perennial weedswith an effective managementprogram before seeding alfalfa. Besure to follow herbicide replantrestriction time intervals beforeseeding alfalfa to prevent herbicidecarryover injury.

11_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

Figure 10. Effect of weed management systems for late-summer seedings on yieldand stand the year following establishment.

Figure 9. Spring and late-summer seeding dates.

70

afa

lfa

sta

nd

(%

)

60

80

90

100

50springseeded

summer seeded

tilla

ge,

her

bic

ide

tilla

ge,

no

her

bic

ide

no

-till

, her

bic

ide

no

-till

,n

o h

erb

icid

e

tilla

ge,

her

bic

ide

2

dry

ma

tte

r (t

ons/

acre

)

4

6

8

0 tilla

ge,

her

bic

ide

tilla

ge,

no

her

bic

ide

no

-till

, her

bic

ide

no

-till

,n

o h

erb

icid

e

alfalfa grass weeds broadleaf weeds

tilla

ge,

her

bic

ide

springseeded

summer seeded

Source: Becker, University of Minnesota, 1993

spring seeding dates

late-summer seeding dates

May 1–30

April 15–May 15

April 1–30

March 15–April 15

July 20–August 1

August 1–15

September 1–15

August 15–Sept. 1

late-summer seeding preferred

spring seeding preferred



Conventional tillage practices varyfrom farm to farm but should consistof a primary tillage (moldboardplowing or chiseling) followed bydisking. Primary tillage loosens thesoil and helps control perennial weedswhile disking controls weed regrowth,helps level the land, and breaks uplarge soil clods. The final tillageshould be some type of smoothingoperation. On level ground, primarytillage is best done in the fall as winterfreeze-thaw cycles help break upclods. It also reduces field operationsin the spring. On erosive soils, falltillage may not be an option.The ideal soil condition for conven-tional seeding should be a smooth,firm, clod-free soil (see picture) foroptimum seed placement with drillsor cultipacker seeders. Avoid over-working the soil as rainfall followingseeding may crust the surface,preventing seedling emergence.

Seed inoculationRhizobium bacteria create nodules onalfalfa roots, allowing the bacteria tofix nitrogen where it becomes avail-able to the plant. While many soilscontain some Rhizobium bacteria fromprevious alfalfa crops, not all fieldshave adequate numbers. To ensure thepresence of the needed bacteria,purchase preinoculated seed or treatthe seed using commercial inoculumavailable from seed dealers. Most vari-eties are preinoculated. These inocu-lant treatments often contain Apronfungicide as well, which protectsagainst diseases that reduce seedlingemergence and kill young seedlings. Iftreating seed yourself, make sure theinoculant was stored in a cool placebefore and after purchase; apply witha sticker—an adhesive compound toattach the Rhizobia to the seed—andthoroughly mix inoculum and seedbefore planting.

Seeding depth and rateAlfalfa is a small-seeded crop andcorrect seeding depth is very impor-tant. Seed should be covered withenough soil to provide moist condi-tions for germination while allowingthe small shoot to reach the surface(figure 11). Optimum seeding depthsvary depending on soil types. Plantseed 1⁄4- to 1⁄2-inch deep on mediumand heavy textured soils and 1⁄2- to1-inch deep on sandy soils. Shallowerseedings may be used when moistureis adequate while deeper seedingsshould be used in drier soils.

80

70

50

60

40

30

20

10

00.5 1.0 1.5 2.0

pla

nt

em

erg

en

ce

(%

)

seeding depth (inches)

6 6

6

6

sand

s

s

s

s

loam

nn

n

nclay


Figure 11. Alfalfa emergence from various seeding depths.

Source: Sund et al., University of Wisconsin, 1966

Soil should be firm enough at planting for a footprintto sink no deeper than 3⁄8 inch.



Seeding rates should be between 12and 15 lb/acre with good soil condi-tions and seeding equipment (table 3).Higher seeding rates do not producehigher yields except under poorseeding conditions. Lower rates arenormally used in arid regions. Whilethese rates may be higher thanneeded for good stands under idealconditions, the wide range of fieldconditions and environmental condi-tions experienced at seeding makethis necessary to obtain consistentlygood stands. For example, extendedperiods of cool, wet weather cancause high seedling mortality (thiscan be reduced by planting Apron-treated seed). Hot, dry weather atseeding time likewise may reducegermination and seedling establish-ment. Under normal conditions, onlyabout 60% of the seeds germinate andnearly 60 to 80% of the seedlings diethe first year (figure 12).An important and often overlookedaspect of planting alfalfa is seedercalibration. Seed size can varybetween varieties and between seedlots of the same variety. Calibrateseeding implements each time youuse a new variety or a new seed lot, orif you use lime- or clay-coated seed.Regular calibration can help to avoidover- or underseeding.

Seeding with and withouta companion cropDirect seeding alfalfa (plantingwithout a companion crop) allowsgrowers to harvest up to two extracuttings of alfalfa and produce higherquality forage in the seeding year ascompared to alfalfa seeded with acompanion crop. However, totalforage tonnage may be less than thatof companion-crop seedings. Someimportant management considera-tions are listed below:

n Select level fields with low erosionpotential for direct seedings; usecompanion seedings where theerosion potential is greater.Erosive soils can be direct seededusing reduced-till or no-tillmethods that leave adequateresidue on the surface.

n Effective weed management iscritical in direct seeding (as nocompanion crop is present). Seethe section on weed managementfor details.

n Harvest the first cutting 60 daysafter germination, regardless ofmaturity stage. This eliminatesmany annual weeds and allowsthe second cutting to reach 10%bloom by September 1 in areaswith short growing seasons.

Companion crops such asannual (Italian) ryegrass,oats, spring barley, andspring triticale help controlerosion, reduce seedlingdamage from blowing sands,and minimize weed competi-tion during establishment.Companion crops alsoprovide additional foragewhen harvested as oatlage orgrain. Straw produced by thecompanion crop is alsovalued as livestock bedding.

Annual ryegrass provides a higher-quality first harvest and greater yieldpotential in the seeding year thansmall grain companion crops. Plantlate-maturing annual ryegrass vari-eties, which remain vegetative in theseeding year (early-maturing typesflower in the seeding year). Seed at 4to 6 lb/acre. For small grains, when companioncrop growth is dense and grown tograin, alfalfa underneath is oftendamaged either by competition or bylodging of the small grain whichsmothers the alfalfa seedlings. Winterwheat, spring wheat, and rye usuallycompete too strongly with alfalfaseedlings and are less desirable ascompanion crops.Following removal of spring-seededcompanion crops, alfalfa regrowthand yield will be largely dependenton moisture availability. One or moreharvests may be possible before thefall critical period. Usually, alfalfaregrowth competes well againstsummer annual weeds; however,herbicide use may be beneficial ifweed populations are high andregrowth is slow. In most of the alfalfa growing regions,companion crops are used only withspring seedings. With summer and

13_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

Table 3. Effect of seeding rate onfirst-year alfalfa dry matter yields.

seeding rate dry matter yield (lb/acre) (tons/acre)

12 3.4

15 3.6

18 3.6

Source: Buhler, Proost, and Mueller, University of Wisconsin, 1988

totalseeds

germinatedseeds

plants afterfirst winter

pla

nts

/ft2

60

50

40

30

20

10

0

Source: Undersander, University of Wisconsin, 1995

Figure 12. Stand density during first 12 months(seeded at 12 lb/acre).



fall seedings, moisture is often limit-ing and competition from thecompanion crop may limit alfalfaseedling development. If companioncrops are needed with summer andfall seeding, the best strategy is to usethe advanced technique described atright.For good alfalfa stands with compan-ion seedings, manage the field to theadvantage of the alfalfa rather than forthe companion crop. Some importantmanagement considerations follow:

n Select companion crop varietiesthat are short, stiff strawed, andearly maturing to avoid lodgingand smothering the alfalfa.

n Seed companion oats or barley at1 to 11⁄2 bushels/acre on heavysoils and 1 bushel/acre on sandysoils to reduce competition forlight and moisture with the alfalfaseedlings.

n Limit nitrogen applications to nomore than 30 lb/acre to avoidexcessive competition and lodgingof the companion crop.

n Harvest the companion crop at theboot stage rather than leaving itfor grain. Harvesting at the bootstage reduces competition withalfalfa and minimizes the chancefor lodging and smothering thealfalfa crop. This harvest stageprovides optimum forage qualityand yield of the companion crop.

n If you do harvest the companioncrop for grain, cut it as early aspossible to minimize lodgingdamage. Remove straw as quicklyas possible to avoid smotheringthe alfalfa stand. Harvestingcompanion crops for grain is notrecommended for good alfalfastand establishment.

n If you plan to harvest the compan-ion crop for grain, considerseeding an early variety in thespring and no-till seeding alfalfainto the grain stubble after harvest.

Seeding equipmentMany different types of drills andseeders are used to seed alfalfa. Allwill produce good stands when plant-ing to an accurate seeding depth in afirm, moist soil.Cultipacker seeders, such as the Bril-lion seeder, broadcast the seed on thesoil surface and then press it into thesoil with rollers. These seeders havebeen a mainstay of alfalfa establish-ment because they give consistentlyeven seed depth placement and goodseed-soil contact for most soils.However, they do not work as well asdrills on very hard ground or on verysandy soil.Drills place the seed in rows, usuallywith 7- to 9-inch spacings, and can


dry

ma

tte

r yi

eld

(to

ns/a

cre)

0

1.0

3.0

2.0

4.0

oatlage

(RFV=107)

companion crop removed with

herbicide at 6 inches

(RFV=154)

directseed

(RFV=145)

alfalfa

grass weeds

broadleaf weeds

oats

Figure 13. First-season yield and relative feed value (RFV) of alfalfa usingdifferent establishment methods.

Advanced techniquesGetting direct seeding benefitswhile controlling erosion

Where the benefits of direct

seeding are desired, yet the need

for erosion control suggests a

companion crop, it may be practical to

seed oats as a companion crop and kill

it with Poast Plus or Select herbicide

when 4 to 6 inches tall. The oats will

control weeds early, provide erosion

control, and protect seedlings from

wind damage. When the oats have

been killed, alfalfa will perform about

the same as in a direct seeding (figure

13). Thus, the erosion control benefits

of a cover crop are achieved while still

getting the higher alfalfa yield of a

direct seeding. The practice may be

particularly beneficial for fields with

steep slopes or long gradients.

Source: Becker, University of Minnesota, 1989



place fertilizer below the seed whereit’s most effective. To improve estab-lishment, use press wheels mountedon the seeder or some other packingdevice, such as a cultipacker, pulledbehind the seeder or used in a sepa-rate pass (figure 14). The mostcommon drills for forage establish-ment are grain drills that can seed acompanion crop simultaneously withthe alfalfa. Grain drills have poordepth control for seed placement.Drills adapted for forages have depthbands to overcome this problem.Alfalfa and companion crop seedmust be put in separate seed boxes.Companion crops should be seeded 1to 2 inches deeper than alfalfa. Thiscan be done in a single pass by placingthe drop tubes for the companion cropbetween coulters and for alfalfabehind coulters (see picture).

15_______________________________________________________________________________________________________________________________________ E S T A B L I S H M E N T ________________

spring seeding

rela

tive

eff

ec

tive

ne

ss

summer seeding0

25

50

75

100

125

band seeder with cultipacker

band seeder withoutpress wheels

band seeder withpress wheels

Figure 14. Importance of packing soil after seeding.

Source: Tesar, Michigan State University, 1984

To plant companion crops 1 to 2 inches deeper than alfalfa in a singlepass, place the drop tube for alfalfa behind coulters but before the packerwheel (a) and place the drop tube for the cover crop between coulters (b).

b

a



Reduced tillage and no-till plantingDue to the high potential for erosionon slopes using conventional tillage, agreat deal of interest has been gener-ated in reduced tillage alfalfa establish-ment. These practices include the useof a chisel plow rather than a mold-board plow, a single pass with asecondary tillage tool, or no tillage atall. Reduced tillage practices are gener-ally successful when careful, timelymanagement is used (figure 15).Crop residue management is animportant factor in reduced-tillageseeding. Chisel plowing or diskingtypically chops the residue finelyenough for conventional seedingimplements to be used. In cornresidue, single disking may give thesame result. Cultipacker seeders willnot perform well with residue levelsabove 35% so a no-till seeder isrecommended. Chopping stalks helpseven the residue in the field and canreduce the amount of residue in thefirst alfalfa harvest.

Special attention must be given toweed management in reduced tillagesystems. When direct seeding, weedcontrol is more difficult as there is lesstillage to decrease weed populations.Perennial weeds are the most difficultto control. Lack of deep tillage maygive some perennial weeds a headstart on the alfalfa. The use of a nonse-lective herbicide, such as glyphosate,to control perennial weeds (preferablyin the previous fall) is critical prior toreduced or no-till seeding. Other weedcontrol options are similar to conven-tional direct seeding and are discussedlater in this publication. Oats can stillbe used as a companion crop.Additional considerations in no-tillalfalfa establishment are soil fertilityand pH. As no tillage is done in theseeding year, materials that work bestwhen incorporated, such as phospho-rus fertilizers and lime, should beapplied and worked into the soilbefore entering into no-till systems. Ifincorporation is not feasible, apply thefinest grade of lime obtainable 1 to 2years ahead of seeding to raise soil pH

in the top inch of soil. (Lime movesdownward at about 1⁄2 inch per yearon silt loam soils and somewhat fasteron coarser soils.) Fine-grade alterna-tive liming materials such as paper-mill lime sludge or cement plant kilndust can also be used.Many implement companies producespecialized no-till seeders for alfalfaand other crops. The design of theseseeders differs among companies butshould have the following features toensure success:

n heavy down pressure,n coulter ahead of disk openers to

cut trash,n double disc openers or an angled

single disc opener,n press wheels, n small-seed box, andn depth control mechanism.

Set seeding depths carefully as theseimplements are very heavy and mayeasily place seed deeper thanoptimum. No-till seeders are often available forrent through Land Conservationoffices, the USDA Natural ResourcesConservation Service, or local fertil-izer dealers and elevators.


0.0

0.5

1.0

1.5

2.0

2.5

3.0

yie

ld (

tons

/acr

e)

1990 1991

moldboard/cultipacker

disk/band seeder

no-till drill

chisel/cultipacker

0

5

10

15

20

25

30

35

pla

nts

/ft2

moldboard/cultipacker

disk/band seeder

no-till drill

chisel/cultipacker

Figure 15. Effect of seeding equipment on yield and stand in seedling year.

Source: Undersander and Mueller, University of Wisconsin, 1992



alfalfa management guide—establishment (1 of 3)

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