Productivity and nutritional value of 20 species of perennial legumes in a low‐rainfall Mediterranean‐type environment in southern Australia

Abstract

In the rain-fed mixed-farming systems of southern Australia, the consistent supply of high-value forage is limited by a range of climatic, edaphic and systems constraints. Over 2 years, we compared biomass production and nutritional value of 30 accessions of perennial legumes, and predicted intake, grazing days and growth of ewes and lambs. There was significant variation in nutritional value and biomass production between and within species. Lucerne (Medicago sativa) and sulla (Hedysarum coronarium) produced the greatest amount of biomass and energy. There was variability among accessions in digestibility (DMD), acid detergent fibre (ADF) and crude protein, and the rate of change in these traits as plants matured. Trifolium species had the highest DMD across all growth stages. Hairy canary clover (Dorycnium hirsutum), erect canary clover (Dorycnium rectum), greater birdsfoot trefoil (Lotus uliginosus), Australian trefoil (Lotus australis) and running postman (Kennedia prostrata) had energy levels that would not maintain liveweight of mature sheep. In the second year, species differed in response to harvesting treatments. Lucerne and sainfoin (Onobrychis viciifolia) were more productive under a frequent cutting regime. Accessions of white clover (Trifolium repens), red clover (Trifolium pratense), alsike clover (Trifolium hybridum), cullen (Cullen australasicum), strawberry clover (Trifolium fragiferum), sainfoin and birdsfoot trefoil (Lotus corniculatus) showed some promise, while Tedera (Bituminaria bituminosa) and milkvetch (Astragalus cicer) performed poorly under the experimental conditions. We conclude by discussing additional agronomic and nutritional factors that need consideration when developing novel perennial legumes for mixed-farming systems in the context of a changing climate.

Near-infrared spectroscopy calibration strategies to predict multiple nutritional parameters of pasture species from different functional groups

“…From this step, C3 legumes and C4 grasses functional group calibrations did not improve the accuracy of any nutritional parameters compared to results obtained using the global calibrations, however, the C3 grasses functional group calibration improved predictions, relative to the global calibrations, for some nutritional parameters (ASH, CP, EE and ADF). Norman et al (2015;2020) investigated the use of NIRS calibrations to predict the nutritional value of grasses, legumes and forbs, concluding that separating taxonomically similar species into groups, did not lead to more accurate predictions than broad, mixed species calibrations. The best-performing calibration models obtained in our study for each nutritional parameter based on optimal wavelengths, mathematical pre-treatments, scattering processing and regression method are summarized in Most models used wavelengths from 400-2500 nm, with the exception of CP which used wavelengths from 700-2500 nm (Table 2).…”

“…In southern Australia, pasture systems are based on a diverse range of grasses and legumes, for which information on nutritional composition under a wide range of environmental (including climatic) conditions is limited (Howden et al, 2008;Lee et al, 2013;Norman et al, 2020;Norman et al, 2021). To address this knowledge gap, we used the Pastures and Climate Extremes (PACE) experimental facility to evaluate the nutritional responses of a wide range of pasture/rangeland species (including tropical/temperate, introduced/native, grasses/legumes) to year-round warming (including intensification of heatwaves) and extreme winter/spring droughts events.…”

Editorial ‐ topics from the XXIV International Grassland Congress held in 2021

“…In a recent special-theme issue of GFS on annual and perennial forage legumes in dryland pasture systems , the role of legumes was addressed in a systems context. Breeding, species choice and regional adaptation (e.g., Bekuma et al, 2021), the development of novel agronomic practices (Harrison et al, 2021) through to animal production and grazing management were addressed (e.g., Gultekin et al, 2021;Norman et al, 2021). Nutt et al (2021) reported on the evaluation of "summer sowing", an innovative approach to increase the adoption of recently domesticated species of hard-seeded annual legumes in Mediterranean and temperate climate zones.…”

“…In a recent special‐theme issue of GFS on annual and perennial forage legumes in dryland pasture systems (Smith & Elgersma, 2021), the role of legumes was addressed in a systems context. Breeding, species choice and regional adaptation (e.g., Bekuma et al, 2021), the development of novel agronomic practices (Harrison et al, 2021) through to animal production and grazing management were addressed (e.g., Gultekin et al, 2021; Norman et al, 2021).…”

Editorial—Annual and perennial forage legumes in dryland pasture systems

“…This is also true with respect to the science on the development and use of legumes in grassland systems. Therefore, this special issue highlights some recent findings from (fundamental and applied) research that covers this spectrum from breeding, species choice and regional adaptation (e.g., Bekuma et al, 2021), the development of novel agronomic practices (Harrison et al, 2021) through to animal production and grazing management (e.g., Gulketin et al, 2021;Norman et al, 2021). Email: kfsmith@unimelb.edu.au…”