Sustainable, low‐input, warm‐season, grass–legume grassland mixtures: mission (nearly) impossible?

Abstract

Grazing lands in warm-temperate and subtropical North America have become less diverse. Pastures are typically grass monocultures, while rangelands are generally managed for the grass components. Overstocking, selective herbicides, fire exclusion and heavy rates of nitrogen fertilizer have contributed to near exclusion of native, warm-season legumes. The simplicity of managing grass monocultures, pasture production responses to nitrogen fertilizer and profitability of grass-only systems have limited interest in legume-based approaches. Changing economics and ecological concerns with ecosystem accumulation of industrial inputs contribute to an increasing interest in legumes. Unlike the development of temperate pasture legumes and recent research in the tropics, legumes tolerant of both freezing temperatures and hot weather have received less attention. Poor establishment, limited persistence and potential invasiveness limit currently available introduced species. Native, herbaceous, warm-season legume species occur throughout warm-temperate North America, but little attention has been directed to these plants as potential forage species. Some success with a few native legume species, primarily in the genus Desmanthus, suggests potential for expanded assessment of forage value of the many species available. Current assessments of native legumes, primarily for conservation purposes, provide an opportunity to expand evaluations of these species for pasture and rangeland potential while economics of livestock production and public interest in ecosystem health are supportive. Experiences with legumes of warm-temperate origin in North America, along with results with temperate and tropical pasture legumes globally, provide a starting point for future efforts at incorporating greater legume diversity in pastures and rangelands of subtropical and warm-temperate regions around the world.

Nutritive value for ruminants of two herbaceous South American native legumes: Adesmia bicolor and Adesmia macrostachya

“…This supports their potential value as forage sources during winter (Dall-Agnol and Gomes 1994;Coelho 1996). In a similar way, several native warm-temperate herbaceous legumes have been described in north-central Texas (USA) that can survive freezing temperatures during winter, with minor decreases to their nutritive value (Muir et al 2011).…”

Restoring Soil Quality to Mitigate Soil Degradation

“…Under West African conditions, construction of stone bunds and establishment of contour vegetative hedgerows can be effective for water conservation [95]. Establishment and management of forage trees (i.e., Acacia fadherbia) [96] and grass-legume mixtures [97] can also improve the quality of rangeland soils.…”

<b>Production and chemical composition of grasses and legumes cultivated in pure form, mixed or in consortium

“…In addition, this cultivation system is a sustainable production strategy. Muir, Pitman, andFoster (2011), Azevedo Junior et al (2012), Lüscher, Mueller-Harvey, Soussana, Rees, andPeyraud (2014), McLeod, Banerjee, Bork, Hall, andHare (2015), and Vrignon-Brenas et al (2016) have all reported that the forage consortium system helps reduce the consumption of chemical fertilizers and pesticides. Multi-species crops also conserve and increase local biodiversity.…”