Yield
In the UK, up to 20 t/ha DM were reported for blue lupin forage cultivated under irrigation during summer (Burtt et al., 1981). In Poland, fresh matter yield from 15.8 to 30.8 t/ha corresponding to 2.2 to 8.8 t DM/ha were reported (Faligowska et al., 2014). In Czech Republic, blue lupin yielded 3.8 t DM/ha in 2017 (Jancik et al., 2017).
Stubble yields were reported to be between 3.75 and 7.5 (-10) t/ha (Gladstones, 1970). Yields of 7 t DM/ha for stubbles, and 2 t DM/ha for seeds from the same crop have been reported (Graham Centre, 2011).
Pasture
Fresh forage
Lupinus angustifolius has been used as a pasture species for a long time. In France, it was grazed by sheep in the early 19th century. Grazing occurred before flowering stage and could be done several times during the growing season. It was also used as green chop and could be cut during winter without losing its nutritive value (Koltz, 1864). In England, blue lupins were used as a sheep feed and for soil improvement in the late 1850s (Oldershaw, 1920). In Australia, sweet varieties of blue lupin have been recognized as a forage readily eaten by sheep at the end of the 19th century. It was used as a winter green feed or as fattening feedstuff during dry spells (Gardner et al., 1929). However, it was also considered as a weed in many parts of Australia and lupinosis outbreaks reduced its use as forage in the middle of the 20th century (Gladstones, 1969). Nowadays, in South Africa, grazing blue lupin is not recommended in the early growth stages, since there is little regrowth, and because of high concentrations of alkaloids in the young leaves and growth points. As the plant matures, more parts of the plant are eaten. For the best value as a grazing it is recommended that it be grazed at an advanced growth stage when most of the growth has taken place (Truter et al., 2015). In the USA, where blue lupin was first cultivated in the 1930s, it was grazed as a winter forage when feed was scarce (Glasscock et al., 1950).
Lupin stubbles
Blue lupin is a valuable grazing option for sheep after harvest of the seeds since it had higher value than cereal stubbles (Gladstones, 1970). It was reported that lupin seed harvest let approximately 150-400 kg seeds/ha on the ground and on stubbles. Lupin has the greatest value during the dry season, when sheep pick up the fallen seeds and graze the stubble (Truter et al., 2015). Lupin stubbles, provided they are not infested by fungi responsible for lupinosis, have a higher protein value than cereal stubbles (DPIRD, 2019). In South Africa, sheep could graze on dry lupin lands from November until late summer (February) rains allow regrowth (Flight, 1956). Mature plants of blue lupins as well as stubbles after seed harvest could also be grazed (Gladstones, 1970).
In New Zealand, a mixed pasture of lupins and cocksfoot (Dactylis glomerata) was sown and compared to alfalfa pasture. This mixed pasture had a production that was 70% of alfalfa but it could grow in areas unsuitable for alfalfa and could be grazed earlier than alfalfa (Hamill, 2015)
For a good stubble management the stocking rate should not be too high as overgrazing may expose the soil to rainfall and wind, and result in erosion (Graham Centre, 2011).
Lupin hay
Dry blue lupin forage could be pen-fed to livestock provided it was not moist. The bitterness of early varieties of blue lupin made it necessary to wait for livestock to get used to it (Koltz, 1864). Lupin plants cut after pod formation and left on swath to dry and make hay were adequately packed in rolls and bales to prevent lupinosis, providing good summer feed to sheep (Allen et al., 1978).
Lupin silage
It was possible to make silage from blue lupin. It was used by farmers in the 1950s in South Africa, where it was recommended to cut it at the young succulent stage, wilt it for 4 days, and add sugars in the form of molasses (3-4%). Because blue lupin could be limited in aminoacids it was also recommended to supplement it with grain or fish meal. Another option was to ensile blue lupin in association with maize or sorghum (Van Zyl, 1973; Van Zyl, 1967; Vosloo et al., 1963). In a more recent experiment in Poland, cutting narrow-leaf lupin at flat pod stage and wilting on the field during 24 hours was found to be effective in reducing fermentation losses and increasing DM content of silage from 20 to 35%. Flat pod stage was suitable because narrow-leaf lupin had higher sugar content and thus fermented better (Faligowska et al., 2014). The addition of lactic acid bacteria improved the quality of narrow-leaf lupin silage (Faligowska et al., 2014). In South Africa, lupin is also used for silage production: its high seed production combined with high green matter yield and high protein content provides a valuable carbohydrates for the silage making process (Truter et al., 2015).
