Alfalfa Management in North Dakota (continued)
R-571 (Revised), November, 1994.
| Harvest Losses Grass-Alfalfa Mixtures Fall Harvest Management Winter Injury Spring Frosts |
Drought Stress Soil Fertility Irrigation Water Management Production Economics |
Harvest Losses
Harvesting losses in field curing of alfalfa can be great, as shown by research in South Dakota. Researchers found that the amount of dry forage recovered in the bale compared with the amount actually present in the field was greatest when forage moisture levels were greater than 40 percent. Dry forage recovered as baled hay averaged 79 percent, but 95 percent was recovered when harvested as haylage (Figure 4). In one instance, two rains amounting to 0.82 and 0.12 inches made it necessary to rake the swaths twice before baling. Forage recovery was 82 percent when swaths were not turned, but only 54 percent when swaths were turned by raking. Principal loss was due to leaf shattering by harvesting machinery. Leaf losses during harvesting increased rapidly at moisture levels less than 30 percent and were especially high at moisture levels less than 20 percent.
Figure 4. Percentages of dry matter
harvested in field curing of alfalfa.
(From SD Farm & Home Research, Vol. 22, No. 3,
Summer 1971)
Reduce leaf loss when field-curing alfalfa by using hay "conditioners," crushers, or crimpers. These machines break the alfalfa stem, allowing a faster, more uniform dry-down of stems relative to leaves. Proper use of drying agents like potassium or sodium carbonate can also reduce drying time, but drying agents do not work well in poor drying conditions. The reduced drying time also reduces the chance of rain before storage. High-moisture hay preservatives like propionic acid applied at a rate of 0.5 to 1.0 percent of wet weight to 25 to 30 percent moisture hay can also reduce harvesting losses and help prevent rain damage.
Grass-Alfalfa Mixtures
Forage yields are generally higher with pure stands of alfalfa in North Dakota where adequate moisture permits a second harvest. Grasses are recommended in mixtures with alfalfa for pasture. Pasture plantings containing 70 percent grass and 30 percent alfalfa have less bloat hazard than pure alfalfa, especially with proper grazing management. Grasses produce the major portion of their growth early in the season, usually permitting only one cutting. Therefore, pure stands of alfalfa or, if mixtures are desired, stands with more than 50 percent alfalfa should be used for highest annual hay production.
Fall Harvest Management
Late summer to early fall is important in the life cycle of an alfalfa plant. The plant must store food reserves to develop cold resistance, supply overwintering respiration, and to initiate growth during the spring. If alfalfa goes into the winter with a low level of food reserves, it is more subject to winter injury or winterkill. However, low root reserves does not dictate that winter injury or kill will occur. Winter injury/kill is determined by environmental conditions (usually a warm spell during late February to early March which initiates loss of dormancy and subsequent killing temperatures). Fall harvest may be detrimental under these conditions, but such environmental conditions are fairly unusual, maybe once every four to six years.
Many experiments have evaluated effects of fall harvest on forage yield and stand survival within North Dakota. Generally, fall harvesting in late September or very early October has increased seasonal productivity (Table 4 and Table 5). Fall harvest date effects were evaluated in a recent experiment at Fargo by harvesting plots at weekly intervals from August 27 to October 28 following a second harvest on July 20 (Table 9). Third-harvest and seasonal forage yields in 1992 were greatest with September harvest of this new stand. Harvesting during October resulted in lower forage yields due to leaf loss following a killing frost. First-harvest forage yields in 1993, however, were greatest from the uncut and October 1992 harvests. About 0.4 tons/acre of the uncut yield was low-quality alfalfa stems from the previous fall, but no residue was left in late October-harvested plots. These data, repeated in 1993-94, suggest that a late September or early October fall harvest should be taken when adequate growth justifies the additional harvest. However, several management experiments suggest that alfalfa should not be harvested during late August or early September. Note that the calendar schedule (Table 5) was the lowest yielding by the third-harvest year. Harvest before or about August 20 or wait for mid to late September.
Table 9. Forage yield in 1993 following weekly harvest in 1992. ------------------------------------------------------ 1992 forage yield 1993 forage yield 1992 third ----------------- ----------------- harvest date Cut 3 Total Cut 1 Total* ------------------------------------------------------ - - - tons dry matter/acre - - - August 27 1.4 6.0 1.6 3.6 September 2 or 9 1.7 6.3 1.6 3.4 September 16, 23, or 30 1.6 6.3 1.7 3.6 October 7 or 14 1.4 6.1 1.9 3.7 October 21 or 28 1.0 5.7 2.0 3.9 Uncut 0.0 4.7 2.1 4.0 ------------------------------------------------------ * Only two harvested, third was lost to drown out.
Taking a fall harvest does slightly increase the risk of winter injury/kill. However, the additional productivity that the fall harvest supplies in most years more than offsets this increased risk.
If you consider taking a fall harvest, be sure you meet the following criteria:
- A winter-hardy variety was used. Varieties marginal in winter hardiness should not be harvested during the fall.
- Soil fertility, especially potassium, is adequate.
- Only short-term (three to four productive years) stands are used. If you plan to maintain the stand for five plus years, a fall harvest probably should not be taken.
- Be sure the alfalfa has reached 15 to 20 percent bloom, has initiated regrowth structures, OR a killing frost has occurred.
- Uncut barriers 1 to 2 feet wide every 30 to 40 feet across the field are left perpendicular to the prevailing winter wind to improve snow cover. If the fall harvest is by grazing animals, be sure to leave a 4 to 6-inch stubble for snow catch. If the fall harvest is the fourth cut, be sure to wait with the harvest until a killing frost has occurred.
Winter Injury
Winter injury or winterkill will periodically occur even with the best management practices. In general, old stands are more likely to winterkill or have winter injury than new seedings or relatively young stands. Several environmental factors may contribute to the degree of winter injury or winterkill. These factors include alternating freezing and thawing, lack of snow cover, wet soil conditions, disease infection, low soil fertility, unfavorable fall weather conditions for plant hardening, and cold temperatures. Grower management practices such as varietal selection, age of stand, and fall-harvest management practices are major considerations for maintaining productive stands.
Alfalfa winterkill is the result of complete killing of plant cells of the crown and root tissues. Stands severely thinned by winterkill will be low yielding and heavily infested with weeds. If winterkill is severe, establish a new stand, but rotating to a new field is best, especially if stands are two or more years old. Alfalfa is known to contain an autotoxic compound which may inhibit immediate re-establishment in the same field.
Winter injury is the result of only a partial destruction or killing of the crown or root tissues. Winter-injured stands are usually slow to begin growth in the spring. The plants may look normal but are weak, stunted in growth, yellowish in color, and they may have a limited number of stems developed per crown. If two to three plants/foot2 remain in most areas of winter-injured stands, satisfactory yields probably will be obtained. If small areas have as little as one plant/foot2, forage yields probably will be adequate since stands established at one plant/foot2 had 78 to 84 percent of yield of full stands. If grass comprises the major portion of the plant population, forage yield should be satisfactory even with a major loss of alfalfa. If only limited areas show winterkill, try no-till seeding of the damaged area and a herbicide to prevent weed competition. Then, do not harvest this area during the first cut only.
Wintered-injured stands require time to heal injured tissues if they are to survive and regain their vigor. Delay harvesting the first cutting until the 50 percent bloom growth stage. The area injured will be just beginning bloom. Early harvest of winter-injured stands may kill the injured plants or keep them in a weakened condition.
Spring Frosts
The growth of each alfalfa stem takes place at the tip. A late spring frost may destroy the growing point of alfalfa, causing a stunting of the plant. A good "thumb rule" to follow is that if one-third or more of the top growth has been wilted by frost and drying up, immediate mowing will permit earlier development of a new crop. If the damage is less, the plant should recover adequately to allow harvest at the normal time. Harvest of frosted stands that were clipped should be delayed to about the mid-bloom growth stage for the second harvest to allow recovery of stored food reserves.
Drought Stress
Drought may restrict or stop the growth of alfalfa at any time during the growing season. Alfalfa under moisture stress may lose its leaves, resulting in low-quality forage. Warm temperatures often accompany drought periods, reducing the time required for the plant to reach maturity. If the maturity of the alfalfa plant has advanced to the flowering growth stage before the drought is broken, the plant will continue to flower and set seed before new growth is initiated from the crown. Regrowth will be slow. The maturing alfalfa will continue to use the limited soil water supplies which could be used for producing a new crop of forage. In general, severely drought-stressed alfalfa should be grazed, or cut for hay if harvestable forage is present, to encourage a new crop once the drought is broken.
Drought-stress effects are reduced by keeping stands young. Young (1- to 2-year old) stands have subsoil moisture available to help maintain productivity (Table 2).
Soil Fertility
The response of alfalfa stands to phosphorus and potassium fertilization has been variable throughout North Dakota. Alfalfa on low-testing soils often will respond to added phosphorus or potassium while alfalfa on soils testing medium to high in these nutrients generally does not respond. Growers should obtain a soil test and fertilize a portion of their fields to determine the potential for yield increases.
Alfalfa is a heavy user of potassium. Alfalfa hay contains from 2 to 3 percent potassium in the forage. Therefore, alfalfa yielding 3 tons/acre will remove from 120 to 180 pounds of potassium per acre. Most North Dakota soils test high in available potassium, so potassium fertilization generally is not needed, with the exception of some sandy irrigated soils. In an irrigated, sandy loam soil in McHenry County, for example, best yields were obtained from alfalfa hay when both phosphorus and potassium fertilizer were applied.
Preliminary studies by the NDSU soils department and extension service field demonstrations indicate that alfalfa stands will respond to phosphorus fertilization when the soil test is about 5 pounds P2O5/acre or less. A dryland alfalfa fertilization study in McHenry County showed a marked response to phosphorus on a soil testing 4 lb/acre. They obtained 4.0 to 4.5 tons/acre when 50 pounds of P2O5 were applied compared with about 2.0 tons/acre without phosphorus fertilization.
Extension service field demonstrations show similar results on grass-alfalfa mixtures. Five-year average forage yields from a fertilizer demonstration in Morton County on a soil testing 2 pounds P2O5/acre was 1.1 tons/acre without fertilization and 2.3 tons/acre with 40 pounds/acre P2O5. Phosphorus fertilization also appeared to increase the percentage of alfalfa in the stand. An application of 30 pounds N and 40 pounds P2O5/acre increased yields to 2.7 tons/acre and maintained the stand of alfalfa.
Alfalfa and grass-alfalfa mixtures containing 30 percent or more alfalfa are fertilized to maintain alfalfa in the stand since alfalfa is a high-yielding, higher-quality forage. Phosphorus increases the ability of the alfalfa plant to maintain itself in the mixture. Nitrogen increases grass yields, but high rates usually increase grass growth and decrease alfalfa in the mixture. In the Morton County demonstration, 60 pounds N/acre applied annually eliminated alfalfa from the stand when harvested at late-bloom growth stages. Alfalfa properly inoculated at planting time will usually not respond to nitrogen fertilization except in very cold soils in early spring.
Phosphorus and potassium recommendations for dryland and irrigated alfalfa based on your yield goal are presented in Table 10 . Note that modest phosphorus and potassium fertilization is recommended on medium testing soils even though a large increase in forage yield is not expected. However, the yield increase will just pay for the fertilizer, and fertilization will help maintain long-term soil fertility. Fertilizer for alfalfa is generally broadcast, although yield increases from deep-plowed phosphorus has been reported in North Dakota.
Table 10. Nutrient recommendations for alfalfa. -------------------------------------------------- Soil test phosphorus, ppm ---------------------------------- VL L M H VH -------------------------------------------------- Yield Bray-I 0-5 6-10 11-15 16-20 21+ Goal Olsen 0-3 8-11 12-15 16+ -------------------------------------------------- ton/a - - - - - lb P2O5/acre - - - - 2 35 25 15 10 0 4 65 50 30 10 0 5 85 60 40 15 0 6 100 70 45 15 0 -------------------------------------------------- --------------------------------------------------- Soil test potassium, ppm ---------------------------------- VL L M H VH --------------------------------------------------- Yield Bray-I 0-40 41-80 81-120 121-160 161+ Goal Olsen --------------------------------------------------- ton/a - - - - lb K2O/acre - - - - 2 105 75 45 10 0 4 195 140 80 25 0 5 245 170 100 30 0 6 295 205 120 35 0 --------------------------------------------------- Bray-I P recommendation = (18.57-0.93 STP)YG Olsen P recommendation = (18.57-1.16 STP)YG Potassium recommendation = (55.71-0.38 STK)YG The abbreviations used in the equations are as follows: YG = yield goal STP = soil test phosphorus STP = soil test potassium
One of the obstacles to good alfalfa production in the United States is maintaining soil pH of 7.0 or higher. In North Dakota, most soils have pH higher than 7.0, so pH generally is not a concern.
Irrigation Water Management
The amount of irrigation water required by the alfalfa crop will vary according to environmental conditions, growth stage, stored soil water, and growing-season precipitation. Water use by the alfalfa plant increases from the time growth begins in the spring until the plant reaches about a 12-inch height or full ground cover. From this stage on, water use averages about 0.25 inches/day until harvest. Studies in North Dakota show that near maximum forage yields are obtained when soil water levels are maintained above 50 to 60 percent of field capacity. Knowledge of the available water-holding capacity of soils and the amount of precipitation between irrigations will serve as a guide to irrigation water application. Several irrigation scheduling methods are available to aid irrigators.
Production Economics
The decision to raise alfalfa has historically been based on the need for forage to feed livestock on the farm rather than on comparable profitability with other crops. The most profitable crop plan in the short run is to devote all acreage to the single most profitable crop, but this increases risk and is generally not sustainable. The crop mix on a farm should consist of those crops that generate the greatest profit long term. This means the sustainability or the risk associated with production and marketing of each crop in that mix must be considered.
Whether used for feed on the farm or sold as a cash crop, alfalfa must compete for alternative uses for land. In some situations, purchasing the needed alfalfa and producing another crop on the farm may be more profitable than producing the alfalfa. This decision should be based on crop budgets which include the three determinants of profitability: production cost, yield, and price.
An alfalfa budget differs from budgets for annual crops in that the seeding and establishment costs need to be prorated over the life of the stand. For the seeding year, these costs seem high relative to many other crops. However, when spread over the full life of the stand these costs are comparable to small grain.
Alfalfa can be harvested as small square bales, large square bales, round bales, chopped as haylage, or stacked as loose hay. The cost of producing hay varies considerably using different harvest methods. In addition to the difference in costs, market price also differs. Prices will vary by regions of the country, but in the Midwest, small square bales usually bring a premium price relative to other harvesting methods. The enterprise budgets in Table 11 outline the cost and returns for alfalfa for southeastern North Dakota harvested as small square bales and as large round bales.
Table 11.
----------------------------------------------------------------------------
Alfalfa - 4 Year Life Round Bales Square Bales Your Figures
----------------------------------------------------------------------------
Dryland Irrigated Dryland Irrigated
----------------- ------------------
Market Yield (tons/ac) 2.3 4.875 2.3 4.875 __________
Market Price ($/ton) $ 55.00 $ 55.00 $ 70.00 $ 70.00 __________
Market Income (/Acre) $126.50 $268.13 $161.00 $341.25 __________
Direct Costs
Seed $ 6.25 $ 6.25 $ 6.25 $ 6.25 __________
Herbicides 3.32 4.94 3.32 4.92 __________
Fertilizer 3.27 8.08 3.27 8.08 __________
Fuel & Lubrication 9.47 11.93 12.54 15.00 __________
Repairs 16.54 17.55 16.79 17.79 __________
Irrigation Expense 39.19 39.19 __________
Twine, Misc. 3.41 5.98 3.41 5.98 __________
Operating Interest 1.85 4.11 1.99 4.25 __________
Sum of Listed
Direct Costs $ 44.11 $ 98.02 $ 47.56 $101.46 __________
Indirect (Fixed) Costs
Misc. Overhead $ 6.39 $ 7.80 $ 6.90 $ 8.31 __________
Machinery Depreciation 24.21 27.98 26.01 29.77 __________
Machinery Investment 12.74 15.47 14.04 16.76 __________
Irrigation Depreciation 25.34 25.34 __________
Irrigation Investment 17.42 17.42 __________
Land Taxes 4.97 4.97 4.97 4.97 __________
Land Investment 34.66 34.66 34.66 34.66 __________
Sum of Listed
Indirect Costs $ 82.97 $133.64 $ 86.57 $137.24 __________
Sum of All Listed Costs $127.07 $231.66 $134.13 $238.69 __________
Return to Labor
and Management ($ 0.57) $ 36.47 $ 26.87 $102.56 __________
Listed Costs Per Ton
Direct Costs $ 19.18 $ 20.11 $ 20.68 $ 20.81 __________
Indirect Costs 36.07 27.41 37.64 28.15 __________
Total Costs 55.25 47.52 58.32 48.96 __________
----------------------------------------------------------------------------
These budgets are based on costs incurred to produce the crop in the field. They do not include any costs associated with storage and marketing. Likewise, the price also reflects the value of the crop in the field at harvest. Storage protection and/or losses can add up quickly. In addition, transportation costs to move alfalfa hay any distance will add considerably to the cost of the hay. Therefore, relating the market value of the hay with the location and time of sale is important. A price of $70 per ton picked up in the field at harvest in eastern North Dakota may be nearly identical to a price of $100 per ton delivered to south central Minnesota six months later.
[ BACK ]
[ Introduction
] [ Stand Management ] [ Age of Stand ] [ Harvest Frequency ]
[ Forage Quality ] [ Cutting Recommendations ] [ Bloom Stages ] [ Stubble Height ]
R-571 (Revised), November, 1994.
