Extension Bulletin E-1536June 1981, File 22.333

Growing Birdsfoot Trefoilin Michigan

By R.H. Leep and M.B. TesarDepartment of Crop and Soil Sciences

Birdsfoot trefoil (Lotus corniculatus L.) is thelongest-lived forage legume in Michigan and thenorthern part of the U.S. Stands of imported birdsfoottrefoil (established in 1949 by MSU at East Lansing)and Empire birdsfoot trefoil (established in 1954 inChippewa County in the Upper Peninsula) are stillproductive. The stands are long lived because theplants are resistant to root rot disease which killsLadino clover and red clover and causes them to bebiennials. Also, birdsfoot trefoil stands last longerthan alfalfa because trefoil produces seed which vol-unteers and forms new plants in late summer or earlyspring.

Trefoil was first grown in the U.P. in 1949 on aone-acre demonstration plot in Mackinac County.Today, trefoil is grown throughout the state on anestimated 70,000 acres with over three-fourths of thatproduction location in the U.P.

Birdsfoot trefoil is adapted primarily to the coolmoist climate of Michigan's U.P. on clay soils too wetfor alfalfa. It is well adapted as a hay, silage, andpasture plant. Since about 1960, it has replaced redclover as the main legume for silage, hay, pasture fordairy and beef cattle in the U.P., primarily because ofits longer stand life. The first cutting in the U.P. (orthe second cutting after the first is harvested in earlyJune) is frequently harvested for seed as a cash crop.

Trefoil is used mostly for pasture in the lowerpeninsula, primarily on erosive soils where longstand life is desirable. It makes excellent pasture forcattle or sheep with no reported bloat damage. Intrials at Michigan State University at East Lansing, ithas produced beef and sheep gains comparable tothose from alfalfa.

PLANT DESCRIPTIONTrefoil is a leafy, fine-stemmed legume which

usually grows 20 to 30 inches high depending uponsoil characteristics and moisture. Many stems areproduced from a single crown. The bright yellowflowers of trefoil are very conspicuous and closelyresemble the color of dandelions. The trefoil plantproduces three to six seed pod clusters which re-semble a bird's foot, hence the common name. The

root system consists of a well-developed taproot withmany branch roots. The taproot does not penetrate asdeeply as that of alfalfa but the branch roots are muchmore developed than those of alfalfa. This helps itsurvive better when frost heaving occurs.

ADAPTATIONRelative to alfalfa, trefoil performs best on the

finer-textured or more poorly drained soils, with amanagement group number of 0-2.5 and/or a "b" or"c" drainage classification, Table 1. Birdsfoot trefoilis less productive than alfalfa on well drained loamsor silt loams (Tables 2 and 3) or on drouthy sandyloams (Table 4). It is not adapted to loamy sands orsands. Alfalfa is much better adapted to such drouthysoils.

Trefoil is very productive on fine-textured soilswith appreciable clay such as those in soil manage-ment groups 0, 1, 1.5, 2.5. If the sandy loams relatedto soil management group 3 are of drainage class (b)somewhat poorly drained or (c) poorly drained, tre-foil is well adapted. It will not survive on muck orpeat soils.

Trefoil will tolerate acid soils (pH 5.0) whichmakes it well adapted to many soils in Michigan.Trefoil has been grown successfully in the U.P. onsoils of pH 4.8. Although it will perform satisfactorilyon acid soils, trefoil responds favorably to liming onacid soils and to phosphorus and potassium fertilizer.

VARIETIES AND PRODUCTIONTwo general types of trefoil — erect or prostrate

— are recommended for use in Michigan. A briefdescription of varieties tested in Michigan ispresented in Table 5.

Viking and Maitland are upright types charac-terized by an erect growth habit, early flowering, andrapid recovery after cutting. The upright type is welladapted to hay and silage production. Leo is less up-right than Viking but more erect than Empire.

Carroll, Empire, and Mackinaw are prostratetypes characterized by a low or decumbent growthhabit. These varieties are best adapted for pasturingsince they will tolerate grazing better than the up-

COOPERATIVE EXTENSION SERVICE • MICHIGAN STATE UNIVERSITY

Table 1. Forage crop recommendations as related to soil management crops.

Dominant profile texture

O - Over 60% clay1 - 40-60% clay1.5 - Clay loam & silty clay loam2.5 - Loam and silt loam3/2 - Sandy loam over loam3/5 - Sandy loam over sand3 - Sandy loam4/1 - Loamy sand over clay4/2 - Loamy sand over loam4 - Loamy sand5/2 - Sand over loam5 - SandM - Organic (muck)

A = alfalfa, T = birdsfoot trefoil

Welldrained

a

TTA,TA,TA,TAAAAAAA—

Natural drainage class

Somewhat poorly drained

Artificialdrainage

b

TTAAAAAAAAAA—

* On very well drained organic soil, use Canadian smooth bromegrass.On less well drained organic soil, use late maturing orchardgrass.

** On undrained organic soil, use reed canary grass.

(Prepared by L.S. Robertson and M. B. Tesar)i

Notdrained

b

TTTTTTTTTTTT—

Poorly drained

Artificialdrainage

c

TTAAAAAAAAAA*

Notdrained

c

TTTTTTTTTTTT**

Table 2. Yields of birdsfoot trefoil and alfalfa at the MSU Beef-Forage Experimental Farm,Lake City, Michigan.

Variety

LeoVikingCarrollEmpire

IroquoisVernal

1974

4.34.03.83.2

4.84.8

1975

3.43.03.12.6

6.25.7

Yield, tons/acre, 12% moisture,

1976 1977

Birdsfoot Trefoil1.71.71.31.3

0.81.0

.9

.8

Alfalfa3.73.7

2.12.1

1978

3.13.02.7'2.3

3.73.8

weed free

1979

2.63.12.32.3

4.95.3

6-yr. Average

Yield

3.43.33.12.7

5.35.3

%ofEmpire

127122114100

197196

Nestor silt loam, pH 6.9, P130, K391, 0+70+210 annual spring topdressing. Seeded Aug. 7,1973, three cuts per year in 1974, 75,and 79 (mid-June, mid-Aug., and mid-Oct.), two cuts in 1976, 77, and 78 (mid-June and mid-Aug. to Sept. 15).

right varieties. Viking and Maitland begin floweringabout 5 to 7 days before Carroll, Empire, and Mac-kinaw (Fig. 1).

Hay yields of varieties evaluated in Michigan arepresented in Table 6 for the U.P., in Table 2 for LakeCity in northern lower Michigan, and Table 3 at EastLansing in south central Michigan. Viking was high-est yielding in two of the three tests and similar toLeo in the third test at Lake City. Viking is an excel-

lent variety because of seedling vigor, adequatewinterhardiness, high yield for hay or silage, andavailability of seed. Empire and other low growingtypes are more suitable for pasturing because of theirprostrate growth habit. The low growing types aremore difficult to establish than Viking because oftheir lower seedling vigor, Table 7. Viking is moredifficult to establish than alfalfa. Stands establishedin summer are satisfactory in Michigan.

Table 3. Yields of birdsfootMichigan.

Variety 1974

Viking 4.6Carroll 4.6Leo 4.6Empire 4.7

Iroquois 7.6Vernal 7.6

Tile drained Capac loam, pH 6.8, P53,May-early June, early July, Aug. 10-25,

trefoil and alfalfa iat the MSU Experimental

Yield, tons/acre, 12% moisture,

1975

4.74.44.54.2

8.17.5

1976 1977

Birdsfoot Trefoil

4.0 2.93.7 2.93.6 2.73.0 2.7

Alfalfa

8.5 8.38.2 7.7

weed free

1978

3.73.33.93.3

7.87.0

1979

2.93.03.02.7

6.56.5

K129, 0+100+300 annual spring topdressing. Seeded Aug. 8,and Oct. 15-30).

Farm, East Lansing,

6-yr. Average

Yield

4.03.93.93.6

7.87.5

%ofEmpire

111108108100

218209

1973, four cuts per year (late

Table 4. Yield and % legumes seeded withpasture, Traverse City, Michigan.

Species with bromegrass

Ranger alfalfaEmpire birdsfoot trefoilPilgrim ladino clover

Ranger alfalfaEmpire birdsfoot trefoilPilgrim ladino clover

1954

4.13.03.1

857070

1955

bromegrass

1956

Yield, tons/acre, 3

4.32.62.7

845735

in 1953

2957

on a renovated

1958 1959

L2% moisture, weed free

3.8 4.62.6 2.92.9 3.1

% legumes in hay

54 3832 16

9 9

3.11.41.6

43109

3.32.12.3

54118

bluegrass

6-yr.Average

3.82.52.6

Emmet sandy loam, pH 6.1-7.4, two hay cuttings /year (mid June and mid- to late Aug.), 0+80+40 fertilizer at seeding and annualtopdressing with 0+80+80 starting in spring of 1955.

Figure 1. Birdsfoot trefoil stands in the second cutting on July6, 1976, at East Lansing one year after seeding. Viking flowersabout one week earlier than Empire and Carroll; Leo is inter-mediate.

CULTURE AND MANAGEMENTBirdsfoot trefoil has lower seedling vigor than al-

falfa and clovers, and does not compete as well witheither a companion crop or weeds in the seedingyear, Table 7. For successful establishment, followthese practices:

Land PreparationFall plow fine-textured soils with poor drainage.

If soils are likely to erode, sow one bushel of oats inthe fall to prevent erosion. Work the land shallowly,keep it free of clods, and cultipack in the spring tohelp insure a firm seedbed. If the soil is heavily in-fested with quackgrass (Agropyron repens L.), con-trol by tillage as indicated below.

Fertilization

Soil test to determine the proper rate of fertilizerand lime. In general, it is not necessary to increasepH above 5.8. A pH of 5.5 is satisfactory but addlime if the pH is below 5.0. When needed, it ispreferable to apply lime 6 months or more in ad-vance of planting. Based on soil test results, applyfertilizer at rates up to 100 pounds of phosphate

(P2O5) plus 100 pounds of potash (K2O) per acrethrough the grain drill, preferably in a band underthe seed. If more potassium fertilizer is needed,broadcast before or after seeding. Controlquackgrass before seeding as indicated under seed-ing methods below.

Table 5. Characteristics of birdsfoot trefoil varieties evaluated in Michigan.

Variety

Viking

Maitland

Norcen

Leo

Carroll

Empire

Mackinaw

Origin

Cornell University,public variety

University ofGuelph, Canada

North Centralstates, publicvariety, releasedin 1981

Macdonald College,Canada, publicvariety

Iowa StateUniversity,proprietaryvariety

Cornell University,public variety

Soil ConservationService, US DA,public variety

Plant Type

Erect, hay type,earliest maturity

Erect, hay type

Intermediate,semi-upright,matures later thanViking, earlierthan Empire

Intermediate,semi-upright,matures slightlyearlier than EmpireSimiliar to Empirebut more upright,matures earlierthan EmpireLow growing,fine-stemmed,late maturity

Low growing,fine-stemmed,late maturity

Winterhardiness

Moderate, generallyadequate for Mich,but greater hardi-ness is desirable

Moderate, similarto Viking

Moderate to high

Moderate to high

High

High

High

Performance

Excellent seedlingvigor, good yieldperformance, goodregrowth

Similar to Viking,yields slightlyless than VikingLimited informationto date in Mich;looks promising

Very good seedlingvigor, yields areas good as Viking

Excellent seedlingvigor, yields areas good as orbetter than EmpireGood tolerance tograzing, adapted towetter soils thanViking

Slightly betterseedling vigor than,Empire, yieldsimilar to Empire

Remarks

Less winterhardy than Empire butadequate for Michigan;good seed productionin MichiganAdapted to sameconditions asVikingMore winterhardythan Viking inMinnesota trials;high yielding;excellent seedproducerPoor seed producer;seed very difficultto obtain

Adapted to samesoil conditions asEmpire; seed dif-ficult to obtainHarder to establishthan Viking

Adapted to samesoil conditions asEmpire

Table 6. Yields of birdsfoot trefoil at the MSU Experimental Farm, U.P., Chatham.

Variety

VikingMaitlandEmpireLeo

Yield, tons/acre, 12% moisture, weed free

1972

3.84.03.93.4

1973

4.14.03.73.9

1974

2.82.72.12.3

1976

2.32.21.41.5

1977

4.64.34.64.2

5-yr. Average

Yield

3.53.53.13.1

%ofEmpire

11311110099

Seedlingn)

vigor

1.71.93.01.5

(1) Seedling vigor rating: 1 = High 3 = LowTrenary loam, two cuts yearly, except only one cut in 1974 and 1976, dry in July and August. Seeded July 1971.

Seeding Date Inoculation

Early spring seeding will normally give best re-sults. April and early May are best for southern lowerMichigan. Late April and May are optimum times forseeding in northern lower Michigan and the U.P.Seeding early allows the plants to take advantage ofspring rains and become well established beforewinter. Summer seedings have also been successfulwith seeding dates of early- to mid-July for northernMichigan and the U.P., or late July to early Augustfor southern Michigan, Table 7. Later seedings inSeptember will generally fail. Plant the slower-establishing "Empire" types about two weeks earlierin summer than the more rapid-establishing "Vik-ing" types.

Seeding Rates and Mixtures

If pure stands of trefoil are desired, use 5-6pounds of certified or high quality seed. For atrefoil-grass mixture, use 5-6 pounds of trefoil seedwith 2 pounds of timothy or orchardgrass, or 4pounds of bromegrass. Bromegrass and orchardgrasscan be mixed with the fertilizer. Timothy can bemixed with the trefoil seed.

In the U.P., trefoil can be seeded satisfactorily onwet clay soils in the spring with oats or barley as acompanion crop in a mixture with red clover. Thered clover becomes established more quickly thantrefoil. In the year after seeding, about 80% of thestand is red clover and 20% is trefoil. In the secondyear, the ratio is about 50-50. In the third year, about90% is trefoil and 10% is red clover. In later years,the stand is almost entirely trefoil.

It is absolutely essential to inoculate birdsfoottrefoil just before seeding with a rhizobia inoculantspecific for trefoil. Alfalfa or clover inoculant will notwork on trefoil. Trefoil will not add nitrogen to thesoil if not inoculated since the rhizobia bacteria arenot in the soil.

Inoculate the seed just prior to planting by mix-ing the seed with a slurry of water and the peat-basedinoculant used double strength. Directions and expi-ration date of the live rhizobia bacteria are on everypackage of inoculant.

Band Seeding is preferred

Band seeding (Fig. 2) with a starter fertilizer isthe preferred method. A grain drill equipped with

Figure 2. The best method for establishing trefoil is to bandseed VA to xh inch deep over a band of fertilizer containing phos-phorus placed 1 to \lh inches deep.

Table 7. Effect of summer seeding date on birdsfoot trefoil yields in the following year.

Method of seeding July 27 Aug. 13 Aug. 27 Sept. 11

AloneOatsOats removed Oct. 3

Average

AloneOatsOats removed Oct. 3

Average

2.16.65.46

1.10

1.32.49.43

.74

Viking Birdsfoot Trefoil

3.621.161.95

2.23

1.69.82.92

1.15Empire Birdsfoot Trefoil

3.38.67

1.42

.70

.52

.70

.31

.52

.63

.48

.25

.79

.64

1.49 .64 .56

Two experiments started in 1960 and 1961 and harvested in 1961 and 1962; 2-yr. avg., Conover loam soil. East Lansing, Michigan.

press wheels or followed by a cultipacker will insuregood soil-seed contact (Fig. 3). Band the seed on topof the soil above the fertilizer band and cover lA to V2inch deep with press wheels or cultipacker.

A Brillion cultipacker seeder (Fig. 4) also workswell for seeding trefoil because it insures shallowseed placement. It has separate seed boxes for thetrefoil and grasses but requires separate fertilizer ap-plication prior to seeding. For more information onseeding methods refer to Extension Bulletin E-1017,"Good Stands for Top Alfalfa Production" (free) andExtension Bulletin E-961, "Clear Seedings of Al-falfa" (free).

Seedings can be made satisfactorily in spring orsummer if quackgrass has been adequately con-trolled and seeding suggestions above are followed.Specific recommendations:

SPRING SEEDINGSeed in early spring — April or early May in

southern Michigan and May in northern lowerMichigan and the U.P. — to get the benefit of cool,moist weather before weeds start.

1. Thoroughly field cultivate or plow old pas-tures in July of the previous year and till soil throughOctober to kill quackgrass and bluegrass (Poa pratent-sis L.) (June-grass). Trefoil will not tolerate grasscompetition during establishment. On clean land,plowing in the spring followed by disking and har-rowing is adequate. As grass-killing herbicides be-come registered for use, they will provide excellentquackgrass control without tillage, Fig. 5, and areparticularly valuable on hilly land and erosive soil.

2. Two alternative seeding methods are avail-able:

Method 1. Clear seed alone, without a companioncrop, using a pre-plant and/or a post-emergenceherbicide to control broadleaved weeds and annualgrasses.How to make a clear seeding. Control annual broad-leaved and grassy weeds with one of two pre-plantherbicides: (1) EPTC (Eptam) 3 pounds active in-gredient (a.i.) per acre is first choice because it con-trols the broadest range of broadleaved annualweeds and annual grassy weeds; or (2) benefin (Ba-lan), Ws pounds a.i. per acre. Spray both on the soiland incorporate into the soil immediately after appli-cation.

One pound of 2,4-DB (a.i.) can be used postemergence when trefoil has one or two leaves with 5leaflets each (about 1 to 2 inches tall). This is usually4 to 6 weeks after seeding. The 2,4-DB can be usedalone or after pre-plant herbicides if a broadleafweed problem develops. 2,4-DB will control broad-

Figure 3. Firming the soil over and above seed helps insuregood stands. A band seeder fertilizer grain drill with presswheels (upper photo) or a cultipacker following the drill effectshallow seeding and firming of the soil over the seed.

Figure 4. A Brillion cultipacker seeder 'places the seed shal-lowly and is an excellent seeding method, particularly in soilswhere phosphorus levels are high.

leaved weeds only. If perennial grasses such asbromegrass (Bromus inermis L.), orchardgrass (Dac-tylis glomerata L.) or timothy (Phleum pratense L.)are seeded with the trefoil, 2,4-DB is the only her-bicide which can be used.

.

Figure 5. A grass killing herbicide (left) or tillage to controlquackgrass is necessary for good trefoil stands.

Figure 6. Seedings of birdsfoot trefoil in oats (left) on a finetextured soil in Chippewa County in the U.P. are very successful.Trefoil on the right was seeded the previous year in oats.

broadleaved weeds with (1) MCPA at % pound peracre a.i. when oats are 6 to 8 inches high (someinjury can result from the use of MCPA); or (2) 1pound of disoneb per acre a.i. to control broad-leaved weeds when the companion crop is 2 to 6inches tall and weeds are small. Disoneb can injurethe crop, especially if sprayed during cloudyweather.

SUMMER SEEDING1. Kill existing sod. Graze old grass pastures or

fields in May. Plow, disk, or field cultivate in lateMay or early June, then till the field every 10 daysuntil late July. If broadleaved perennials (such asCanada thistle) are present, spray with 1 pound 2,4Dester a.i. 10 days prior to tillage. Sods which areheavily infested with quackgrass can be controlledby this system. Sods with bluegrass, orchardgrass,bromegrass or other grasses with not require as muchtillage.

2. Band seed or seed as above in spring seedingwith 5 to 6 pounds inoculated seed per acre. Fertilizeas described under fertilization.

3. Seed grass as described in seeding rates andmixtures above.

4. Seed in late July or early August, no later thanAugust 10 in southern Michigan or mid July innorthern lower Michigan or the U.P.

5. Normally, fall frosts will kill annual weeds insummer seedings. Downy brome and commonchickweed can be controlled by an early Novemberapplication of Kerb 50-W at one pound a.i. per acre.

Method 2. Seeding with oats is much less reliablethan clear seeding alone with a herbicide. Seedwith 1 bushel of early-maturing oats removed (1) forpasture when 8 to 10 inches tall and regrazed again;or (2) for silage. Do not leave the oats for grain sinceexcessive competition will generally result in seed-ing failures.

Seeding with oats is not likely to be successfulon drouthy sandy loams but has been a very goodmethod of establishing trefoil on wet clay soils inthe U.P. (Fig. 6). Seeding with oats has resulted inmany failures in lower Michigan, probably becauseof drouthier soils and excessive competition fromthe oats, Table 7. In lower Michigan, seedings withEptam or Balan preplant or 2,4-DB post emergenceare much more reliable and preferred seedingmethods than seeding with oats.

When trefoil is seeded with oats or barley, seedthe oats at no more than one bushel per acre usingan early maturing stiff-strawed variety. Control

SOD SEEDINGSeeding of trefoil in herbicide-treated sod with-

out plowing (Fig. 7) is another method of establish-ing trefoil and improving yield and protein content ofgrass pastures. Sod seeding is not recommended un-less the soil is too steep for safe tillage or is likely toerode excessively. Pastures which are primarily Ken-tucky bluegrass, timothy, bromegrass, or or-chardgrass are the best sites for sod seeding becausethese species can be suppressed adequately byparaquat herbicide. Do not sod seed on sods pre-dominately quackgrass, since it will compete toovigorously with trefoil.

There are many types of seeding equipmentavailable for sod seeding. A regular fertilizer-grain-legume drill can be adapted for the purpose. Foradditional information on sod seeding of trefoil, referto Extension Bulletin E-956, "Sod Seeding BirdsfootTrefoil and Alfalfa" (free).

Figure 7. Sod seeding birdsfoot trefoil in Dickinson County inthe U.P.

HARVEST AND STANDMAINTENANCE

The following practices will help you maintaingood stands of trefoil:

1. Graze no closer than 3 inches to maintain goodstands.

2. Graze grass early in trefoil-grass stands, thenremove animals until trefoil blossoms for better qual-ity forage and more persistent stands of trefoil.

3. Cut trefoil for hay when it begins to flower.You can normally take 3 cuttings in southern Michi-gan (Tables 2 and 3) and 2 cuttings in northernMichigan (Table 6).

4. Topdress annually with fertilizer for increasedyields and stand persistence. One ton of trefoil haywill remove 10 pounds of phosphate and 30 to 40pounds of potash per acre. Trefoil fertility trials con-ducted on a poorly drained clay loam (Table 8), inthe U.P. suggest a yield response up to 25 poundsper acre from applied nitrogen. The soil tested 23pounds P per acre and 480 pounds K per acre. Atthese test levels the fertilizer requirement was 50pounds P2O5 and no K2O per acre. Maximum yieldswere obtained with a fertilization rate of 75 poundsof P2O5 and 50 pounds K2O per acre. Topdressing

MICHIGAN STA

COOPERATIVEEXTENSIONSERVICE

Figure 8. Kerb herbicide applied November 1-20 at W2 lb.active ingredient per acre removes quackgrass effectively from aViking trefoil stand invaded by quackgrass at Lake City in north-ern Michigan.

with additional potash on fine-textured soils testinghigh in potassium is advisable.

5. If annual broadleaved weeds become a prob-lem, clip or graze as low as possible for effectivecontrol or use 2,4-DB at 1 pound per acre a.i.applied in early spring.

6. Control quackgrass before planting trefoil orit will compete severely with, and generally kill, tre-foil seedlings. If quackgrass starts to dominate trefoilstands as the stand gets older, spray with Kerb 50-Wat YV2 pounds per acre a.i. applied in late fall (Nov.1-20) when soil temperature falls below 60PF, (Fig.8). For more information on weed control, refer toExtension Bulletin E-434, "Weed Control Guide forField Crops" (Price 400).

PESTSInsects

Although insects have not been a problem in tre-foil forage production, a few insects cause losses.The meadow spittlebug (Philaenus spumarius L.),feeds by sucking sap from the plant, resulting instunted plants and aborted flower buds. The potatoleafhopper, (Empoasca fabae), causes a yellowing orreddening of leaves and stunting of plants. Forageyield and quality may be reduced when heavy infes-tations of the potato leafhopper occur. Another suck-ing insect, the alfalfa plant bug, (Adelphocorislineoletus), destroys stem terminals and flowers, re-ducing seed production of trefoil when the crop isharvested for seed. In general, spraying of trefoilgrown for forage is not economical.

DiseasesCrown and root rots are the most important dis-

eases of trefoil, but these diseases are more likely tobe problems in southern states. They are seldom aproblem in Michigan. Many fields of trefoil inMichigan have been in production for over 15 yearswith no apparent disease problems.

This information is for educational purposes only. Reference to commercial products or trade names does not imply discrimination or indorse-ment by the Cooperative Extension Service. Cooperative Extension Service Programs are open to all without regard to race, color, national origin,or sex. Issued in furtherance of cooperative extension work in agriculture and home economics, acts of May 8, and June 30,1914, in cooperationwith the U.S. Department of Agriculture. Gordon E. Guyer, Director, Cooperative Extension Service, Michigan State University, E. Lansing, Ml48824- 1P-1OM-KMF-6:81-UP, Price 25<2, Single Copy Free to Michigan Residents

Table 8. Effect of N, P andI K upon yield ofViking birdsfoot trefoil on a poorly drained clayloam* in the U.P.

Annualtreatment,N+P2O5+K2O

lbs/acre

0+0+025+75+050+75+00+37+00+75+00+150+00+225+00+75+500+75+1000+75+200

Yield tons/acre 12% moisture

1978

1.032.241.881.541.621.982.272.062.251.68

* Soil test -23 lb P, 480 lb K per acre.

1979

2.754.063.913.042.723.122.993.642.753.09

2-yraverage

1.893.152.892.292.172.552.632.852.502.38