Brachiaria: a versatile forage for sustainable agriculture

Brachiaria grass species are found in natural grassland and originated primarily from Africa (Boonman, 1993), their capacity to grow on acidic soil with low fertility has made them an important forage grass, especially in South America where Brazil alone count 99 million hectares of land sown with Brachiaria species (Jank, Barrios, Valle, Simeão, & Alves, 2014). Despite being originally from Africa, the improvement of pasture through selection that took place in eastern Africa in the 1960s and 1970s did not include Brachiaria specie. Thus, the grass did not benefit from the scale-up promoted by commercial agriculture which resulted in only a small number of African countries cultivating the specie including Congo, Uganda and Kenya (Boonman, 1993).

Despite being originally excluded for pasture improvement, several recent projects pushed the come back of Brachiaria in Africa. This come back is due to its high forage quality, drought stress resistance, and several other characteristics of the grass making it a useful addition to agriculture and forage systems (Maass et al., 2015).

Brachiaria species aptitude to grow in a wide range of habitats allow its presence in agriculture for a wide range of utilisation: in coffee plantations in Kenya to restrain soil erosion and as a supplement income through its use as green manure, in maize fields to curb the spreading of armyworms, in brazil integrated with grain crops to reduce pasture degradation and many more.

For example, a selection of Brachiaria specie has been recently adopted for integration into a climate smart crop production technology called “push-pull” which have been widely adopted by small-holders in Kenya, Ethiopia, Uganda and Tanzania. The role of Brachiaria in this system is due to its ability to produce volatile chemical compounds influencing stem borer insects to come lay their eggs while also attracting natural enemies to destroy them. In the “push-pull” system, Brachiaria is intercropped with Desmodium which possess mechanisms that lead to in situ suppression and elimination of Striga hermonthica, a parasitic plant that causes heavy damage to cereal production in Africa (Khan et al., 2002; Midega et al., 2015). This technology answer two of the most prominent threats to cereal production in Africa while providing small holders with fodder and an additional income through the sale of Desmodium seeds.

As described in the home page of this blog, some Brachiaria species have potential for mitigation through their high BNI potential (Moreta et al., 2014) . Recently another feature with potential benefits for mitigation was identified by an Indian team working in environmental engineering. They determined that a Brachiaria-based constructed wetland was efficient at removing phosphate and nitrogen from wastewater and thus could be used for both fodder production and water treatment (Nandakumar, Pipil, Ray, & Haritash, 2019).

Finally, the findings of one of the newest papers from CIAT, in cooperation with the Department of Sustainable Soil and Grassland Systems in Devon (UK) add onto the agricultural benefit of Brachiaria. The authors advise that the impact of forage on soil health should be a key trait when selecting varieties. Amongst the species included in the experiment leading to this conclusion, two Brachiaria cultivars with BNI potential also showed potential in improving soil health (Horrocks et al., 2019).

The efforts deployed these last years in the study of Brachiaria species have expanded further the knowledge of important natural processes for the development of sustainable and eco-friendly agriculture in sub-tropical regions. Keeping on the research and development of forage varieties such as Brachiaria is key to improve livestock system and for the development of sustainable mitigation in agriculture.