LUPINE (Lupinus). Leguminosce. Fig. 595 A large group of leguminous plants mostly con fined to western North America, a few species occurring in eastern United States, in the southern states and in the Mediterranean region, some of them valuable for green-manuring and forage. Upwards of one hundred species are found in the western United States. Most of the species are her baceous annuals or perennials, although a few are shrubby. The agriculturally valuable species are all annuals. Those most cultivated are native of the Mediterranean region. All are showy plants with conspicuous flowers in terminal racemes or spikes, borne on long peduncles. The flowers are blue, white or yellow, or a union of these, papilionaceous and free-blooming. The leaves are usually digitate, with five to seventeen entire leaflets.
Lupines are grown primarily as a green-manure crop. Their great value for this purpose depends on their ability to thrive on poor sandy soils and on their high nitrogen content. In Europe, large tracts of sandy soils have been brought into con dition for profitable cultivation by green-manuring with lupines and fertilizing with phosphates and potash salts. As a forage crop, the cultivated lupines are of no great importance, and are but little used for this purpose. All of the species are rather coarse for fodder.
Lupines are hut little cultivated in the United States. In Europe and North Africa there are four species in cultivation, namely, the white (L.
the yellow (L. luteus, Fig. 595. adapted from Botanical Magazine). the blue (L hirsutusl, and the Egyptian (L. termisl. Of these, the yellow Itipme is used most extensively, the blue and white I ipMes being next in importance. In parts of the ),V,st, a number of species, notably L. leucophyllus an 1 L. serio us, grow wild in great luxuriance and are cut for hay. The numerous American native species are of considerable value on the ranges, many of them being eaten readily both by sheep and cattle. Some danger attends the feeding of this hay, especially to sheep, owing to the pres ence of a poisonous alkaloid in the seed. [Consult Vol. III.] The cultivated lupines have been tested at many of the American experiment stations, mostly with decidedly unsatisfactory results. Only on the Pacific coast have the cultivated lupines appeared at all promising as green-manure crops, and even there other legumes are more satisfactory. Up to the present time, none of the species has become espe cially valuable in the United States. It is not at all unlikely, however, when it shall become prof itable to build up some of the sandy soils in the West, that one or more of the European species may prove valuable. One of the species, native to
California (L. affinis), has been grown there as a green-manure crop and compares favorably with the European species.
sandy, well-drained soil is essential, as the plants will not grow on wet land, and are par ticularly averse to limestone soils. Their greatest value is on poor, sandy soils that will not grow anything else. On the other hand, it was found at the California station that lupines would tolerate much more lime on clay soils than on sandy soils. It is said that the large blue lupine (L. pilosus, var. cveru/eus) and the pink lupine (L. pilosus, var. roseus) are adapted to limestone soils.
salts give the most beneficial results, although the addition of phosphates with the potash is profitable. Superphosphates have given detrimental results and should not be applied to the soil on which the lupines are to be sown.
seed is usually sown at the rate of eighty to one hundred pounds per acre in drills ten to fifteen inches apart. If broadcasted, nearly double this quantity is required. The seed should he sown after the ground is warm, the early part of May or June being the usual time. The plants grow rapidly and are ready to plow under in the early part of August, by which time they will have developed seed and will contain the maxi mum amount of nitrogen.
Place in the used in a rotation, espe ciaily on lands that are being built up, it is prefer able to follow lupines with winter rye. In this case, at least a month should be allowed to elapse after the lupines are plowed under, before the rye is sown.
Utilizing the crop.
The native American species are pastured throughout the growing season. If cut for hay, it should not be harvested until the pods bare ripened and burst open and scattered their seed. This occurs the latter part of August or first of September.
The seed of the cultivated species is very rich in protein and is used in Europe to some extent as feed. The feeding value is much lessened by the presence of a bitter alkaloid which is injurious to animals, especially to sheep. Before feeding the seed, it is necessary to remove some of the alkaloid by soaking or boiling. One method is to boil the seeds for one hour and then to wash them for twenty-four hours in running water. This re sults in a loss of about one-sixth of the dry, principally non-proteid matter. The disembittered seed is then fed in much the same way as oil cake.