SIRIWAN MARTENS, PATRICIA AVILA, LUIS H. FRANCO, MICHAEL PETERS
International Center for Tropical Agriculture (CIAT), Tropical Forages, Colombia
The cover crop legume Canavalia brasiliensis can be grown on a wide range of soils: soil pH 4.3-8.0, low fertile soils and up to a height of 1000 m .a.s.l. The annual Vigna unguiculata shows even a wider range of environmental adaptation.
The high level of crude protein of these legumes suggests a good suitability as feed supplement for ruminants and possibly even for swine.
Canavalia brasiliensis CIAT17009 and Vigna unguiculata CIAT9611 were established in September 2007 at Palmira station, Colombia, in quadruplicate. Each plot had a size of 5 m x 3m. Row-spacing was 70cm and within rows 30cm or 20cm respectively for Vigna at a sowing rate of 20kgha-1.
Canavalia was harvested at 8, 12, 16 and 20 weeks of growth, Vigna at 6, 8, 10 and 12 weeks. Yield, feed value and ensilability were determined.
The dry matter yield of Canavalia developed slowly from 1.1tha-1 after 8 weeks of growth to 3.6tha-1 after 12 weeks, then to 6.1tha-1 at 16 weeks and 12.3tha DM after 20 weeks. The DM content rose from 21 to 24% from 8 to 16 weeks, and to 39% after 20 weeks. The fast growing Vigna started with a DM yield of 1.7tha-1 (6 weeks), and increased to 3.5, 5.1 and 8.5tha-1 with 8, 10 and 12 weeks, respectively. Vigna had a high water content in the stems, resulting in a total DM of 11-13% until 10 weeks. Only in the final stage of pod ripening the DM content rose to 21%.
Throughout the weeks 6 to 10 Vigna had a high in vitro DM digestibility (IVDMD) for ruminants of > 74% and a CP content of 20-17% in DM in comparison to 59-65% IVDMD and around 16% CP of Canavalia from 8-20 weeks. When Canavalia was used on-farm as a supplement in Nicaragua, it improved the performance of dairy cattle (van der Hoek, this volume).
Keywords: Canavalia brasiliensis, feed value, yield