D.H. Putnam1, E.S. Oplinger2, L.L. Hardman1, and J.D. Doll2
1Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108
2Department of Agronomy, College of Agricultural and Life Sciences and Cooperative Extension Service, University of WisconsinMadison, WI 53706. Nov., 1989.
Lupine cultivation is at least 2,000 years old and most likely began in Egypt or in the general Mediterranean region. The lupine plant, like other grain legumes (beans, peas, lentils, etc.) fixes atmospheric nitrogen, and produces seed high in protein. There are over 300 species of the genus Lupinus (L.), but many have high levels of alkaloids (bitter tasting compounds) that make the seed unpalatable and sometimes toxic. Historically, lupine alkaloids have been removed from the seed by soaking. But plant breeders in the 1920's in Germany produced the first selections of alkaloidfree or "sweet" lupine, which can be directly consumed by humans or livestock. White lupine (L. albus L.), yellow lupine (L. luteus), and blue or narrow-leafed lupine (L. angustifolius) are cultivated as crops. Lupines are currently grown as a forage and grain legume in USSR, Poland, Germany, the Mediterranean, and as a cash crop in Australia, where it is exported to the European seed markets. Both winter-hardy and non-hardy types are available.
Sweet white lupine is high in protein (3238%), low in oil (10%), TDN (7580%), and does not contain trypsin inhibitors. The seed can be fed directly without heat treatment and has been successfully fed to turkeys, calves, lambs, swine and lactating dairy cattle. Methionine is a limiting amino acid and may be required in rations for poultry and swine.
When animals graze lupine stubble, a disease called lupinosis can develop. It is caused by a mycotoxin. Symptoms are loss of appetite and jaundice. Lupinosis has been a problem in sheep grazing in Australia and in Europe.
In Minnesota trials, a complete replacement of soybean meal with lupine meal for dairy cows resulted in a reduced feed intake and a slight reduction in milk production. The current recommendation is that lupine can replace up to 65% of the soybean meal (10% of the total mix) in a diet. Calves fed ground lupine as the only supplemental protein source in starter diets showed no decrease in production compared to a soybean meal diet.
Lambs fed whole lupine seed grew at the same rate as lambs consuming soybean meal at the same level of protein, indicating that lupine can replace up to 100% of the soybean meal in lamb diets.
Current Minnesota recommendations are that white lupines are unacceptable for growing pigs (under 225 lbs). A 1988 Minnesota study reported a 2% reduction in feed intake for each 1% lupine in the diet. This translated directly into a reduction in gain. Pigs are quite sensitive to alkaloids and palatability can be a problem when alkaloid levels exceed 0.04% of diet dry matter (most sweet lupines are less than 0.03%). Even at this level, feed intake of lupine diets can be severely reduced due to a problem with palatability. Better feeding has resulted from using the yellow and blues lupine species.
Turkey rations containing up to 15% lupine in the diet have not decreased production compared with soybean meal diets. Larger quantities result in reduced feed intake and gain, probably because of fiber content. Methionine should be added as a supplement.
The United States has a developing specialty human food market for lupine in the form of lupine flour, lupine pasta, and hulls for dietary fiber. Sweet lupines have been shown to increase the protein and fiber crops in conjunction with durum wheat in specialty pastures, and to be an excellent source of white-colored fiber, as an additive to breads and cereals.
The growth habit of lupine is different from other grain legumes. Emergence is epigeal (cotyledons emerge above ground before development of true leaves), and early seedling growth is considerably slower than later vegetative stages. Maximum vegetative growth rate occurs during flowering. The main stem and each branch usually terminate in an inflorescence, which is a simple raceme with varying numbers of flowers. Even aher the main stem flowering has ceased, the plant can develop lateral secondary as well as tertiary flower sets from a sequence of lateral branches. Species and cultivars differ in ability to set pods on these secondary and tertiary branches. The process is highly influenced by environmental conditions.
Lupine is adapted to well-drained, coarsely textured, neutral to acidic soils. Iron chlorosis and disease problems often result from plantings on poorly drained, higher pH soils. Reports from Minnesota, New York and parts of New England indicate that many lupine production problems are due to planting on soils too heavy, too wet, or too high in pH. An area of adaptation in central Minnesota on the more acidic, better drained soils has been identified, as have other localized areas in the state. Many alkaline soils with high clay content are considered inappropriate for lupine production.
Results from trials conducted in Minnesota and Wisconsin (Table 1) show that planting in early to mid-April results in maximum grain yields. Large yield reductions from plantings after early May have been reported at several locations. The primary requirement is to plant early enough to complete flowering before the excessive heat of early summer. Planting too early, when cold affects the seed, can sometimes result in vernalization which causes a determinant growth habit, reduced plant growth, and lower yield. Since the importance of this process is poorly understood, it is recommended that growers plant in mid-April in most of Minnesota & Wisconsin, but when freezing temperatures begin moderating.
Table 1: Date of seeding effect on lupine yield. Minnesota and Wisconsin.
|Location||Year||April 1015||April 28May 2||May 1620||June 520|
Yield increases between 37110% have been achieved in Minnesota and Wisconsin trials by narrowing row spacing from 30" to 6". Lupine planted in narrow rows has also been reported to mature earlier. But since lupine can be susceptible to weed infestations, some growers may need to use wider row spacings to allow for cultivation.
Seeding rates of 6 plants/ft2 (255,000 seeds/A or 170 lbs/A) for narrow rows and 7080 lbs/A in wider (30") rows are recommended to maximize yield and compete effectively with weeds. Slightly higher yields or improved plant population result from higher seeding rates, but high seed costs encourage lower seeding rates. White lupine has very large seed so planting equipment must handle the seed without damaging it.
Control of seeding depth and rate is crucial to successful stand. The large-seeded lupine requires aufficient moisture for germination, but planting too deep can cause failure due to seedling diseases. A depth of 3/4 1-3/4" is recommended depending on soil type and condition.
Soil fertility recommendations for lupine have not been fully developed, but the requirements are probably similar to field bean or soybean. No yield differences have been observed due to application of P, K, S or micronutrients to lupine in five years of study at Staples, Minnesota.
Yield increases of nearly 60% have occurred in Minnesota due to inoculation of the seed with the specific nitrogen fixing bacteria for lupine (Rhizobium lupini) on fields not previously planted with lupine. Since inoculant is inexpensive, lupine seed should bc treated to insure good N availability. Lupine is relatively efficient in fixing nitrogen from the atmosphere, but the crop response to fertilizer N has not been determined.
The lupine crop, like other grain legumes, often increases the nitrogen content in the soil the following year, when compared to fallow or non-legume crops. The extent and utilization of this contribution remains open to question. In one Minnesota study, nitrate-N was increased significantly in only one of four locations. Current evidence suggests that under most soil conditions (especially on sandy soils), lupine harvested for grain does not leave significant amounts of N in the soil for the following crop. These results are similar to those obtained from field bean and soybean studies. A "rotation effect" of increased cereal yields after grain legumes (compared with cereal-cereal rotations) can still occur due to other factors. Wheat yields following lupine were greater in two of four Minnesota locations.
Several varieties of white, blue, and yellow lupine have been developed worldwide. Experimental selections are currently being evaluated in Minnesota, Wisconsin and North Dakota. In 1988 the most commonly grown variety in Wisconsin and Minnesota was Ultra, however seed of Primorsky, Kiev, and other varieties were available.1
Lupine is a poor competitor with weeds, and is slow to develop a full canopy. For this reason effective weed control is essential for success with this crop. Poor lupine performance in Minnesota and Wisconsin has often been associated with poor weed control. A particular problem at many locations is late-germinating annual broadleafs, such as lambsquarters, pigweed and ragweed; fields with excessive populations of these weeds should be avoided.
Select fields free of perennial weeds like quackgrass, milkweed, bindweed, Canada thistle, etc. Avoid fields with atrazine residues and high levels of annual weed seed buildup in the soil. Early planting will give the crop a headstart on many weeds.
1. Mechanical: Lupine is often planted in narrow rows (7 to 10 inches apart) where row cultivation is not feasible. However, a rotary hoe is safe to the crop and effective on many annual weeds it done at the right time. Inspect fields every 4 to 5 days after planting and rotary hoe when a flush of weeds has germinated and is just beginning to emerge. Rotary hoeing lupines is similar to using this implement in soybeans: a few crop plants will be killed but the benefits greatly exceed the loss. Follow the planter wheeltracks to avoid compacting additional area between the rows. Rotary hoe when soils are relatively dry, and drive at least 5 MPH. If the crop is grown in rowscultivate.
2. Chemical: Two herbicides currently registered for use in lupines are Prowl and Dual. A tank mix applied before planting and incorporated uniformly to a 2-inch depth is suggested. Product rates and incorporation methods are the same as for soybean. If lupines become a commonly grown crop, additional herbicides will most likely obtain EPA registration.
Lupine disease organisms are present in most fields. All varieties currently grown are susceptible to root rots caused by Rhizoctonia and Fusarium fungi. These diseases are credited with some reductions in yield throughout the region, especially on heavier, poorly drained soils. Phytophthora and Pythium have been a problem under certain conditions. Ascochyta and Botrytis stem canker have also been reported. The only protection against these diseases is resistant varieties. Unfortunately, genetic resistance is not yet available so avoid sites with excessive soil moisture and higher pH.
Corn seed maggot has been reported to reduce lupine stands by more than 50% in New York state, and has been a severe problem some years in Minnesota. This problem could be aggravated by high organic matter and fresh manure application, which attract adult insects. Chemical insecticide treatments on the planted seed may deter some maggots. Potato leaf hopper and tarnished plant bug (Lygus bug) have been observed in Minnesota and Wisconsin lupine fields and have resulted in zero pod set and yields in lupines planted in mid-May in Wisconsin.
Lupine planted in April generally will be ready for harvest during August in southern Minnesota and Wisconsin and September in northern areas of these states. Lupine is resistant to lodging and shattering under most conditions and there is usually ample distance between the soil surface and the lowest pod. Moisture content of the seed at harvest should be 1518% to reduce damage. Under certain environmental conditions, a large percentage of the plants in a field can remain vegetative late in the season. Late broadleaf weeds have also been an impediment to a clean harvest. Such fields should be winrowed and dried prior to combining.
Lupine has responded to favorable growing conditions by producing yields up to 70 bushels/acre in north-central Minnesota under irrigation. Average yields in many Minnesota and Wisconsin Experiment Station trials have been much lower and vary widely by location and year (Table 2).
In Wisconsin trials conducted under the drought conditions in 1988 yields ranged from 9 to 42 bu/A (Table 3).
Such variation demonstrates the importance of proper management practices and suggests that the risk for this crop may be higher than for other crops. As with all new crops, you should start with a small acreage and expand only with experience.
Table 2: Average lupine yields at Minnesota Experiment Stations, 197275 and 198186.
|Location||No. Test Years||Treatment||Average Yield|
Table 3. Average lupine yields at Wisconsin locations, 1988.
Australia exports substantial quantities of lupine for the European livestock feed market, and a Minnesota company has started to explore this market. The first export shipment of U.S. grown lupine (primarily from Minnesota and Wisconsin) to the Netherlands occurred in Fall, 1987.
Because of this diversity of use, lupine demand is unpredictable. This is the case with most minor crops. The price of lupine has been determined by the price of soybean meal or whole soybean. For example, one company sets the price of lupine equal to soybean or at 80% of the current soybean meal price.
The ability of a farmer to make a new crop enterprise work depends on both market and biological risk factors. For lupine, the production risk at this time seems to be more important than the market risk, since the market is relatively diverse. However, no grower should consider producing lupine as a cash crop until markets are fully investigated.
The cost of chemical weed control for lupine is about the same or slightly less than soybean (from $822/A). However, cultivation can eliminate this cost for lupine. Seed cost for lupine currently is $3640/A compared to $812 for soybean, so the total costs of production are slightly higher for lupine.
Calculated break-even yield for these cash expenses is given in Table 5, using a $5 market price for soybean and lupine. The actual price of lupine has been about 8090% that of soybean. The percentage of experiment station trial yields which have exceeded this amount is also shown. These data demonstrate the risk of lupine compared to soybean. It is important to remember that some of these locations (Tables 2 & 3) were not appropriate for lupines, and that the probability for success with lupine will be increased by planting in specific areas of adaptation.
Table 4: Estimated production cash costs* for soybean and lupine (Central Minnesota & Wisconsin).
|Repairs & maintenance||16.64||16.64|
|Interest on cash Exp.||4.00||4.00|
Table 5: Break-even yield level for cash expenses and percentage of Minnesota Experiment Station yield trials which have exceeded this amount.
|Crop and Treatment||Calculated Break-Even Yield1||Trials Exceeding Break-Even Yield||Number of Tests|
1In the MinnesotaWisconsin region, the white springsown lupine varieties have performed best. New varieties are becoming available; see "Varietal Trials of Farm Crops", Item AD-MA-24, Univ. of Minnesota Agric. Exp. Station.