Alfalfa

Alfalfa is the oldest cultivated forage crop in the world (i.e. forage crop that was consciously planted by farmers).

The word alfalfa derives from the Arabic meaning ‘best fodder’.

It is known as ‘Lucerne’ in Europe and is native to Asia and Mediterranean countries.

First documented cultivation was in a region spreading from Iran to northern Pakistan.

Obviously cultivation was associated with livestock domestication.

Alfalfa is an herbaceous perennial legume that grows from a semi woody base or crown.

Under ideal growing conditions it can live for 20 years or more.

Medicago sativa L. from the Poaceae family is the most commonly grown species.

Flowers of commercial cultivars are almost completely self incompatible.

Seed set requires flowers to be ‘tripped’ by wind or insects (i.e. leaf-cutter bees).

Alfalfa

First introduction of alfalfa into the USA was in Georgia in 1736.

Initially it was grown in the eastern states but rather unsuccessfully.

Alfalfa was introduced to California from Peru in 1841 and later from Chile in 1850 and thereafter started a great expansion in acreage.

Wendelin Grimm introduced winter-hardy strains into Minnesota in the mid-1800’s which increase use of the crop in the cooler regions.

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Alfalfa by County

Jefferson - 498,500 tons Bingham - 325,800 tons Cassia - 285,200 tons Owyhee - 282,000 tons Elmore - 273,000 tons Jerome - 249,100 tons

Common alfalfa (Medicago sativa spp. sativa)

Chilean (Spanish) alfalfa: was imported from Chile; first alfalfa grown in Kansas; vary in cold tolerance and fall- spring-growth habits

Turkish alfalfa: originated in Russia, Iran, Afghanistan and Turkey; vary from moderately to very winter-hardy; generally susceptible to leaf and stem disease but resistant to insects.

Flemish alfalfa: were developed in France; known to be vigorous and stemmy in growth habit; early maturing and recover quickly after cutting; moderately resistant to foliar diseases

Yellow-flowered alfalfa (Medicago sativa spp. falcate) are not grown commercially in the US

Variegated alfalfa (M. sativa ssp. x varia):

Derived from a natural cross between common alfalfa and yellow flowering types (M. varia).

Mainly purple flower but brown, green-yellow, yellow and white flower can be found.

More cold resistant than common types.

Responsible for the successful cultivation in the US northern states.

Crop Establishment

A vigorous 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 as needed;

Selecting an adapted and high yielding variety;

Using appropriate cultivation and seeding practices to ensure good seed germination and crop establishment.

Alfalfa requires well-drained soil. Wet soils create disease conditions that will reduce yield and kill plants.

Soils should be deep and have adequate water holding capacity. Under favorable conditions alfalfa roots may penetrate 20 feet deep, giving the crop excellent drought tolerance.

Fields should be free from perennial weeds such as Bermuda grass and free from any herbicide carry over. Apply herbicides pre-planting as appropriate.

Bermuda grass Bind weed

Curly dock Johnson grass

Annual bluegrass Nettle

Chickweed Knot weed

Wild Mustard Shepherds purse

Yellow star thistle Dodder

Weed

Herbicide

Eptam Treflan

Grasses Barnyard grass G G

Foxtails G G

Quackgrass P N

Wild oat F P

Broadleaf Nightshade P P

Kochia F G

Landsquarter F F

Pigweed F/G G

Ragweed P N

Velvetleaf F/G N

Wild mustard P/F N

Weed

Herbicide

Buctril 2,4D Poast Select Pursuit/Raptor

Grasses Barnyard grass N N G G G

Foxtails P N G G G

Quackgrass N N F/G F/G P/F

Wild oat N N G G F

Broadleaf Nightshade F/G F N N G

Kochia F/G F N N G

Landsquarter G G N N F/G

Pigweed F/G G N N G

Ragweed G G N N F

Velvetleaf G G N N G

Wild mustard G F N N G

Alfalfa seed is produces in the drier regions in the western states (California and Idaho).

Seed production row spacing is 20 to 40 inches.

Seeding rates are 1 to 3 lb/acre, and populations not to exceed 1,000 plants/acre.

Low moisture early in season promotes slow vegetative growth.

Most flowers produced from second flush.

Avoid sprinkle irrigation during pollination.

Combine after windrow.

Average seed yield is 200 lb/acre but can be 500 to 1,000 lb/acre

Leafcutter bee

Leafcutter bee

Alfalfa can be planted in spring or early fall.

Late planting should occur before mid-August to allow seedlings to become well established before winter dormancy.

Dry land seeding rates are 8 to 12 lb/acre; irrigated seeding rates are higher at 15 to 20 lb/acre.

It is common to cross plant (i.e. 50% planted north-south and the remaining 50% east-west).

Seeding depth should be 0.5 to 0.75 inches, and less in heavier soils.

3.3

3.35

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3.55

3.6

3.65

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% plant emergence Tons/acre

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Plants/ft2 % of check

Reseeding alfalfa within 1 year carries a risk of yield and stand failure due to autotoxicity.

If reseeding consider: Disk down a seedling failure and reseed either in

late summer after a spring seed or the following spring.

Reseed gaps in original seeding as soon as possible.

Never interseed in a stand over 2 years old. May look okay initially but new seedlings will die out due to competition for light and moisture.

In cases with poor alfalfa establishment consider interplanting with red clover or a forage grass (i.e. rye grass)

Fertilizer applicators

Harvested alfalfa removes large quantities of nutrients from the soil.

Each ton of alfalfa removes 60 lbs of nitrogen; 12 lbs of phosphorus; and 60 lbs of potassium.

Additional amounts of nutrients need to be applied periodically over the life of the crop stand.

Application is dependant on tissue of soil analysis.

Alfalfa is a legume and should fix most of its own nitrogen if it is sufficiently nodulated by viable Rhizobium meliloti.

Efficiency of N fixation depends on adequate levers of P and S.

Excessive soil acidity and soil pH values less than 5.8 disrupts N fixation.

Consider seed inoculation with Rhizobia with soil pH less than 6.2.

Apply 30 to 35 lb N/acre will

aid seedling establishment

and growth while root nodules

are forming.

However, excessive levels of

inorganic N (NH4+ and NO3-) will prompt invasion of grassy weeds and reduce nodulation and quantity of N fixed by the crop.

When establishing alfalfa seedlings incorporate phosphorus fertilizer into the top 3 to 6 inches of the seedbed.

Adequate phosphorus is critical for rapid and successful plant stand establishment.

On established crops, fall or winter applied phosphorus is preferred.

Phosphorus can be incorporated into the seedbed or applied on established crops in large enough quantities to last 1 to 3 years.

Soil test P (0 - 12 inches) P2O5 application rate*

NaOAc** Bray 1 NaHCo3

1-year supply

2-year supply

3-year supply

(ppm) (ppm) (ppm) (lb/a) (lb/a) (lb/a)

0 – 2 0 – 20 0 – 8 60 105 150

2 – 4 20 – 40 8 – 14 40 66 92

4 – 8 40 – 80 14 – 20 15 25 50

Over 8 Over 80 Over 20 0 0 15

* P2O5 x 0.44 = P or P x 2.29 = P2O5

** Soil test determined by: NaOAc = sodium acetate; Bray 1; NaHCo3 = sodium bicarbonate.

Alfalfa removes large amounts of potassium from the soil.

When establishing seedlings incorporate potassium into the seedbed.

On established crops fall or winter application is preferred.

Application can last 1 to 3 years.

Prior to cutting collect tissue samples from to 1/3 of plants. Potassium should be 1.7 to 2.0%. If less than 1.5% consider fall application for next season crop.

Soil test K (0-12 inches)**

K2O application rate *

1-year Supply

2-year Supply

3-year Supply

(ppm) (lb/acre) (lb/acre) (lb/acre)

0 to 35 90 165 240

35 to 75 60 110 150

75 to 100 40 70 90

Over 100 0 Resample soil

* K2O x 0.84 = K or K x 1.20 = K2O ** Sodium acetate-extractable K

On acid soils (pH values less than 5.8) lime needs to be added to maximize alfalfa yields.

An acid soil reduced dramatically the nitrogen-fixing potential of the crop.

Soil pH values of 5.8 to 6.5 are desirable.

pH values higher than 6.5 may promote Phosphorus deficiency problems.

If soil pH between 5.5 and 5.8 apply 1 ton of lime/acre.

If soil pH is less than 5.4 apply 2 ton of lime/acre and incorporate lime before seeding.

Alfalfa responds to Sulfur application.

Add 25 lb S/acre if less than 4 ppm S in soil test.

Increase rate to 35 lb S/acre if soil contains large amounts of volcanic ash.

Add 1 to 1.5 lb Boron/acre based on soil test less than 0.5 ppm Boron. Do note exceed more than 2 lb B/acre.

There has never been any suggested response to adding any other micronutrients (i.e. zinc, copper, manganese, iron, cobalt or chlorine).

Once an alfalfa crop has been established it is necessary to:

Maintain soil nutrients;

Scout and control pests and disease;

Decide when to harvest fodder;

Decide when to rotate out of alfalfa.

Harvested alfalfa removes large quantities of nutrients from the soil.

Each ton of alfalfa removes 60 lbs of nitrogen; 12 lbs of phosphorus; and 60 lbs of potassium.

Additional amounts of nutrients need to be applied periodically over the life of the crop stand.

Application is dependant on tissue of soil analysis.

Nutrient Low Sufficient High

------------------------- % ----------------------------

Nitrogen < 2.50 2.50 – 4.00 > 4.00

Phosphorus <0.25 0.25 – 0.45 > 0.45

Potassium < 2.25 2.25 – 3.40 > 3.40

Calcium < 0.70 0.70 – 2.50 > 2.50

Magnesium < 0.25 0.25 – 0.70 > 0.70

Sulfur < 0.25 0.25 – 0.50 > 0.50

Water use of alfalfa is estimated as evapotransporation (ET).

In alfalfa ET normally varies from 0.1 to 0.35 inches/day.

This results in a season water use of 35 inches/year in Idaho.

In the PNW it takes 5 inches of water to produce 1 ton of alfalfa (@85% efficiency = 6 inches)

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Harvest: 1st 2nd 3rd 4th

Max. pivot capacity

Maximum pivot capacity = 6.5 gal/minute, 85% efficiency.

Begin season with full soil water profile.

Monitor the soil profile weekly for moisture content.

Soil water should be depleted to 50% of the available water in the top 2 feet just before harvest.

Begin irrigation as soon as hay/silage has been removed from the field.

------Relative Seriousness ---

Serious Moderate Slight

Annual weeds cocklebur green foxtail lambsquarter

nightshade pennycress pigweed

giant foxtail shepherds purse common ragweed

giant ragweed

yellow foxtail

Perennials curly dock Canadian thistle dandelion

hoary alyssum quackgrass white cockle

Bacterial wilt: is the most serious alfalfa disease in the US. Most severe in northern states, moderate-severe in Idaho. Usually appears in the 3-5th crop year. Most noticeable after cutting in regrowth.

Anthracnose: Occurs most often under warm moist conditions and can cause 25% yield loss. Severe in south east, not serious in Idaho.

Aphanomyces: is a serious problem in wet soils. Infected plants show yellowing symptoms like N deficiency. Severe in all northern states.

Common leaf spot: Occurs primarily in the first and second cuttings. Severe in all northern states.

Aphanomyces root rot

Bacterial wilt Anthracnose

Common leaf spot

Sclerotinia: Crown and stem rots is most damaging at seedling stage, especially when seeded in late summer.

Verticillium wilt: can reduce yield by 50%. Often infects second year and can reduce crop life.

Fusarium wilt: is a vascular disease that causes stand thinning. Severe in all northern states.

Phytophthora root rot: Can kill seedlings or established plants in wet slowly drained soils. Severe in almost all regions.

Fusarium wilt

Sclerotinia Verticillium wilt

Phytophthora root rot

Alfalfa weevil: Larvae chew and skeletonize leaves. Large populations can defoliate entire plants, giving the field a grayish appearance. Severe in south-east, moderately severe in Idaho.

Aphids: cause stunting and yellowing of alfalfa plants. Moderate to severe all states.

Blister beetle: In alfalfa hay can cause sickness and death in livestock, particularly horses.

Variegated cutworm: Most serious on regrowth. Moderately severe all states.

Blister beetle

Alfalfa weevil Aphids

Variegated cutworm

Decision to rotate out of alfalfa is related to plant stand counts and actual crop yield.

New seedlings should have 25-30 plants per square foot in the seedling year.

Ideally actual yield will determine whether to rotate out.

Possible to estimate yield based on stem counts.

In Northwest and other irrigated regions, yields often begin declining in the third year.

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Stems per square foot

Yield = (0.10 * stems) + 0.38

Relative Feed Value or Relative

Feed Quality

Acid Detergent Fiber

Neutral Detergent Fiber

> 151 < 31 < 40

151 – 125 31 – 35 40 – 46

124 – 103 36 – 40 47 – 53

102 - 87 41 – 42 54 – 60

86 – 75 43 – 45 61 – 65

< 75 >45 > 65

•Heifer, 18-24 mo. •Dry cow •Idle horse

•Brood mare •Working horse

•Heifer, 12-18 mo. •Beef cow with calf

•Dairy, last 200 days •Heifer, 3-12 mo. •Stocker cattle

•Nursing mare •Hard-working horse

•Dairy, 1st trimester •Dairy calf

100 110 120 130 140 150 160

Relative feed value/relative forage quality

Alfalfa is a perennial that stores carbohydrates (sugar and starch) in the crown and roots.

Plants use carbohydrate reserves for regrowth after each cutting.

Regrowth begins with buds wither on the crown or at the base of old shoots.

Regrowth for the 2nd and later cuttings begins while growth from the previous cycle begins to flower.

Cut at bloom

Cut at bud

Growth initiation

6-8 inch height

Bud stage

Flower stage

Alfalfa forage quality is greatest in the early vegetative stages when leaf weight is greater than stem weight.

Higher forage yields after early flower can be attributed mainly from low-quality stems.

Alfalfa grown in cool weather has higher quality than when grown in warm weather.

Vegetative Bud First flower

Full flower

Post flower

Leaf yield

Stem yield

Total yield Forage digestibility

Forage quality is determined by time of day when cut.

Plants convert sugars and starch to energy (respiration).

Nest time to cut alfalfa is morning to speed drying and capture sugars and starch for higher quality

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Cutting Interval (Days after May 25)

June 1 July 1 Aug 1 Sept 1 Oct 1 Nov 1

35-40 days 35-40 days

28-33 days

28-33 days

30-35 days

38-55 days

30-35 days

No cutting recommended

No cutting recommended

Harvest Option

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Hay Harvest

Alfalfa hay is herbage fine chopped and cured for forage.

In alfalfa pre-bloom has 22% protein and 25% fiber, while seed is 14% protein and 37% fiber.

Alfalfa hay is most commonly cut using a sickle-bar cutter, and laid in wind-rows.

Dried (cured) in field by air drying. Time from cutting to harvest is dependant on (1)

volume of material to be dries and drying temperature.

Harvest is completed by, bailing, chopping or stacking.

Can be stored in the field, stacked or stored under tarp or in barns.

Practice Reason Benefit

Mow forage early in day

Allow full day drying

Faster drop in moisture; less respiration loss; less likelihood of rain damage.

Form into wide swath

Increase drying rate

Faster drop in moisture; less respiration loss; less likelihood of rain damage; higher quantity and quality.

Rake at 40-50% moisture content

Increase drying rate

Faster drop in moisture; less respiration loss; lass likelihood of rain damage; less leaf shatter; higher quality and quantity.

Bail hay at 18-20% moisture content

Optimize preservation

Less leaf shatter; inhibits mold and browning; low chance of fire; higher quantity and quality.

Store hay under cover

Protect from rain damage and sun

Inhibits molds and browning; less loss from rain damage; higher quantity and quality.

Silage

Silage is a forage crop that is preserved in succulent condition by a process of fermentation (i.e. under anaerobic conditions).

Corn silage (102 million ton); Sorghum silage (4 million ton).

Also can use forage grasses (i.e. timothy) and legumes (alfalfa, stover, and soybean).

Can be harvested under wet condition.

More expensive to make cw hay but has better nutritional value.

Grain harvest at 15%. May be higher if drying is used.

Corn silage when grain at 35% moisture. Begin at ¾ milk stage.

May start earlier but yield will be lower.

History – derived from process of curing high-moisture or ‘sour hay’ in 19th century Germany.

Originally used in crop mixtures grown with legumes such as alfalfa and clover.

Almost all corn grown in western Europe goes into silage.

Corn is the most common type of silage.

Other crops may be ensiled, i.e. triticale,

juvenile corn, beet tops, and sunflower.

Silage additives can help in the

fermentation process (i.e. homofermenter

lactic acid bacteria)

Silage

Basics of ensiling Relatively high moisture: 60 to 70%

Earlier harvest for corn or other cereal requires swathing, and wilt or drying.

Air tight storage: Tower, trench, bunker, tubing.

The supply of oxygen is limited and fermentation brings about the decomposition of carbohydrates into acetic, butyric and lactic acids.

Narrow cross-section to length for sequential access.

The closeness with which the fodder is packed determines the nature of the resulting silage by regulating the chemical reactions that occur in the stack.

When closely packed the product is named sour silage.

If the fodder is unchaffed and loosely packed, it is called sweet silage.

In some cases, sour silage acquires a most disagreeable odor, but it keeps better than sweet silage when removed from the silo.

Basics of ensiling-timeline

2 to 4 hrs respiration consumes oxygen.

2 to 3 days fermentation replaces 60 to 70% of atmosphere with CO2. Sugars converted alcohol then to lactic acid.

2 to 15 days Temperature in silo rises to

100o F

12 to 17 days Fermentation process will

be complete.

Cows 30 to 40 lb/day

Yearling cattle 15 to 20 lb/day

Sheep 4 to 5 lb/day

Fattening cattle 25 to 35 lb

/1000 lb live wt.

Crop %

Moist

Crude

Protein

Ash Carbo-

hydrates

Corn silage 60 8.3 7.1 59

Alfalfa silage 65 20.1 8.4 38

Silage

Practice Reason Benefit

Minimize drying time

Reduce respiration

Reduce nutrient and energy losses; more sugar for fermentation; lower silage pH.

Chop at correct length (3/8th inch); fill silo quickly; seal silo carefully

Minimize exposure to oxygen

Reduce nutrients and energy losses; more sugar for fermentation; less browning; faster pH decline; better aerobic stability; less chance of listeria; less protein solubilization.

Leave silo closed at least 14 days

Allows complete fermentation.

Lower silage pH; more fermentation acids; better aerobic stability; less chance of listeria.

Unload 2-6 incher/d.

Stay ahead of spoilage

Limit aerobic deterioration.

Discard deteriorated silage

Avoid animal health problems

Prevent toxic poisoning; mycotic infections; prevent listeriosis; clostridial toxins.

Dairy Production, 2001 to 2009 (million pounds)

• PNW currently has 929,000 dairy

cattle.

• PNW imports over 1 million tons of

seed meal into the region annually.

• Equivalent to 2,740 tons per day

Winter

Harvest

Canola

Plant

canola

Cut 1 Cut 2 Cut 3 Cut 4

Harvest

Canola

Apr May Jun Jul Sep Jan June Aug Jul

Winter

May

Plant

canola

Timeline

Dual purpose crops can

increase profit for single crop.

Demand for high quality

forage produced on site.

Increase crop rotation

flexibility.

Cover crop.

y = -1E-05x2 + 0.0209x - 5.1491 R² = 0.694

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DM

Yie

ld (

Mt

ha

-1)

Growing Degree Days

Athena

Baldur1,045 AGDD = 5.77 Mt ha-1

Forage Yield

y = -0.0014x2 + 2.8134x + 212.19 R² = 0.4092

800

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2200

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$

Accumulated Growing Degree Days

Seed only = $1,010

1,011 AGDD = $1,625 return

Gross Return

Time

Traditional

Forage

Canola

Forage

Forage Harvest

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Triticale Alfalfa Canola

Relative Feed Value

Silage Type

Forage Mixtures

Crop Yield DM

tons/acre %

Canola 3.6 10.6

Canola-Wheat 4.8 19.1

Canola-Pea 3.5 10.6

Yield

Crop CP ADF NDF CF Ash RFV

-------------------- % ------------------- ---

Canola 19.0 15.3 21.7 4.4 14 335

Canola-Wheat 16.7 20.0 33.6 3.6 13 258

Canola-Pea 17.9 16.8 24.1 4.1 13 312

Quality

Grain harvest at 15%. May be higher if drying is used.

Corn silage when grain at 35% moisture. Begin at ¾ milk stage.

May start earlier but yield will be lower.

High-moisture corn above 20% (HMC).

High Moisture Corn

Pit Construction

Processed HMC

Packing HMC in pit

Covered HMC pit

HMC pit

Tomato

(Lycopersicum esculentum)

Pepper

(Capsicum annuum)

Crop Species