The Potential for Capturing the Forage Yield of White Lupin by Intercropping with Cereals

Abstract

ABSTRACT The usefulness of sweet white lupin (Lupinus albus L.) as a grain legume in Atlantic Canada is limited by excessive vegetative growth and late and uneven seed maturity. Lupins were intercropped for silage with oat (Avena sativa L.), wheat (Triticum aestivum L.) or maize (Zea mays L.) at Truro, Nova Scotia, Canada, to evaluate dry matter (DM) and crude protein (CP) yields and forage percent DM. Oat and wheat were intercropped with lupin at either 100% of the regular monocrop lupin population plus 50% of the monocrop cereal population (LMED) or at 75% of the monocrop populations of both crops (LLOW). Lupin and cereal were sown either simultaneously (S-sown) or with cereal planting delayed 4 weeks (D-sown) in a complete two x two x two factorial. Lupin and maize were intercropped in a separate two x two factorial at two row spacings (in alternate 38-cm rows or in the same 76-cm rows) and at the same two population densities as the small grain cereal intercrops. Biomass and CP yields of lupin monocrops and D-sown intercrops were not different, but D-sown cereal yields were substantially reduced from their monocrops. Total biomass yields of S-sown oat and wheat intercrops ranged from 6030–6790 kg ha−1 in 1991 and 8710–9940 kg ha−1 in 1992 compared with lupin monocrop yields of 5910–8120 kg ha−1. Percent dry matter (DM) of S-planted intercrops was within the acceptable range for ensiling. Population and cereal species had significant main effects on DM and CP yields of component species only. Yields of maize intercrops ranged from 7410 to 9980 kg ha−1 while the maize monocrop averaged 14500 kg ha−1. Land Equivalent Ratios (LERs) for DM of the S-sown, LMED intercrop were 1.27 and 1.16 in 1991 and 1992, respectively, while the corresponding LERs for CP were 1.53 and 1.40. Dry matter LERs for S-planted oat intercrops ranged from 1.00–1.08, but maize LERs were less than one in 1991. Increased land use efficiency and acceptable forage DM levels indicate lupin/wheat intercrops have promise as a silage crop.