Pasture Legumes Research Articles

Australian Grassland Association research symposium 2023: pasture legumes for sustainable productive systems

Australian Grassland Association research symposium 2023: pasture legumes for sustainable productive systems

An agronomic study of legacy effects from annual legume pastures in acid soils

AbstractThe use of acid soil‐tolerant annual legume pasture species and liming to raise soil pH can have legacy effects that improve subsequent wheat crop growth in acid soils. We established a two‐year experiment in a semi‐arid environment with and without historical lime application to investigate how acid soils (±lime) influence the legacy effects of annual legume pastures. We measured legume and cereal growth and yield, soil‐borne disease incidence, rhizosheath organic acid type and amount, legume biological nitrogen fixation (BNF) and soil moisture in Year 1, and soil microbial biomass carbon (MBC) and wheat yield and quality in Year 2. Minor differences in soil moisture and soil‐borne diseases occurred between cereals and legumes, and the poor BNF contribution of all pasture legumes improved in lime treatments. Pasture legumes produced more organic acids than cereals, which increased in limed treatments. Soil MBC in Year 2 was greater following legumes than cereals. Year 2 wheat grain yield increased following pasture legumes, more so in limed treatments. The contribution of organic acid exudation by annual legume pastures to microbial community legacy effects warrants further scrutiny in semi‐arid environments, particularly when acid soils limit typical rotational benefits.

White clover from the exclusion zone of the Chernobyl NPP: Morphological, biochemical, and genetic characteristics

A comprehensive study of the biological effects of chronic radiation exposure (8 μGy/h) in populations of white clover (Trifolium repens L.) from the Chernobyl exclusion zone was carried out. White clover is one of the most important pasture legumes, having many agricultural applications. Studies at two reference and three radioactively contaminated plots showed no stable morphological effects in white clover at this level of radiation exposure. Increased activities of catalase and peroxidases were found in some impacted plots. Auxin concentration was enhanced in the radioactively contaminated plots. Genes involved in the maintenance of water homeostasis and photosynthetic processes (TIP1 and CAB1) were upregulated at radioactively contaminated plots.

Managing interspecies competition to improve spring pasture maturity, nutritive value, and biomass

AbstractIn much of the United States, wet springs often cause poor field conditions leading to harvest and/or grazing delays and subsequent reductions in forage nutritive value. The objective of this study was to compare monocultures and combinations of orchardgrass (Dactylis glomerata L.), chicory (Cichorium intybus L.), and white clover (Trifolium repens L.) to determine the effects of interspecies competition on plant maturity, nutritive value, and forage mass over two consecutive springs. It was hypothesized that shade and competition from chicory would delay orchardgrass maturity resulting in greater nutritive value and an extended harvest or grazing window for high‐nutritive value forage. Mixtures containing chicory delayed orchardgrass maturity by at least 9 days in the first spring as compared to orchardgrass monocultures and orchardgrass‐white clover mixtures. Even with decreased chicory mass in the second year (due to drought and winterkill), both 1:1:1 and 4:1:1 (ratio of seeds per hectare) orchardgrass–white clover–chicory mixtures provided greater forage mass and nutritive value (crude protein and net energy) yield over 2 years compared to an orchardgrass monoculture; however, only the 1:1:1 orchardgrass–white clover–chicory mixture provided greater benefits to forage mass and nutritive value yield when compared to orchardgrass–white clover mixtures that are commonly found on farms. This study showed that chicory inclusion provides benefits to orchardgrass and orchardgrass–white clover pastures when planted in appropriate seed proportions; however, increasing chicory longevity will require further investigation to provide continued benefits in perennial cool‐season grass and legume pasture systems.

Vegetation dynamics in nitrogen‐fertilized versus mixed legume‐smooth bromegrass pastures interseeded with sorghum‐sudangrass

AbstractInterseeding annual warm‐season grasses may increase forage and pasture productivity. From 2017 to 2019, we conducted a grazing experiment that examined smooth bromegrass (Bromus inermis Leyss.) pasture responses to interseeding sorghum‐sudangrass [Sorghum bicolor (L.) Moench × S. bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan]. The experiment had a split‐plot design with six main plots each containing two, 0.60‐ha pasture subplots (i.e., 12 total subplots). The six main plots included three replications each of two pasture types: (A) nitrogen (N)‐fertilized smooth bromegrass (FERT) and (B) mixed legume‐smooth bromegrass [LEG; alfalfa (Medicago sativa L.), red clover (Trifolium repens L.), and birdsfoot trefoil (Lotus corniculatus L.)]. The subplots included sorghum‐sudangrass interseeded and unseeded control treatments. Each pasture subplot, which supported two steers (Bos taurus) from spring through summer, contained six, 0.10‐ha sub‐subplots for rotational stocking. Sorghum‐sudangrass was interseeded after stocking cycle 2 in two of the sub‐subplots in the interseeded subplot each year. Vegetation responses were evaluated in these sub‐subplots and in two adjacent sub‐subplots in the unseeded control subplot. Across years, sampling dates, and subplot treatments, the LEG main plots supported 7% greater forage biomass (2743 ± 102 kg ha−1) and six more grazing days than the FERT main plots (2552 ± 111 kg ha−1). Sorghum‐sudangrass interseeded sub‐subplots, however, had 36% greater forage biomass than unseeded sub‐subplots pre‐grazing in stocking cycle 5. To optimize forage biomass, producers should fertilize in early spring or maintain legumes in smooth bromegrass pastures. Interseeding sorghum‐sudangrass provides an option to increase late‐summer forage biomass.

Effects of soil amendments on hairy vetch no‐till interseeded into a hayfield

AbstractIncreasing the abundance of legumes in mixed pasture and hayfield stands can improve forage nutritional quality and nutrient cycling; however, establishing legumes can be difficult, especially without tillage or chemical suppression of existing vegetation. Soil amendments that reduce the competitiveness of the existing plant community or improve the vigor of interseeded legumes could reduce the need for more intensive management practices at the time of interseeding. We compared a range of commercially available soil amendments for their effects on the no‐till establishment of hairy vetch (Vicia villosa Roth) interseeded into an existing sod. Amendment treatments were applied in September and included wood ash, biochar, lime, and K applied at different rates, and unamended tilled and untilled treatments as controls. Hairy vetch was no‐till interseeded immediately after treatment application and biomass was measured the subsequent June. Results were consistent across the two site‐years and indicated that an intermediate rate of wood ash (8967 kg ha−1) increased hairy vetch biomass in the spring by 8.5 and 12.4 times compared to the tilled and unamended controls, respectively. We used nonparametric multiplicative regression (NPMR) to explore the relationship between soil physical and chemical properties and hairy vetch biomass across a range of wood ash application rates. We found that soil K alone explained 42% of the variability in hairy vetch biomass. This research suggests that wood ash soil amendments may improve the chances of successfully interseeding legumes into perennial forage crops without the use of herbicide or tillage to suppress the existing plant community.

Survival analysis of germination data in response to temperature for Ornithopus species and other temperate pasture legumes.

Cool temperatures can limit productivity of temperate grazing systems as poor pasture growth rates in winter create feed shortages for livestock. Ornithopus spp. (serradella) are broadly adapted annual pasture legumes that produce high-quality forage in soil types considered marginal for other temperate legume species. However, serradella establishment is perceived to be difficult in cool-season environments. We used survival analysis to compare germination rate and seedling emergence for two serradella species (yellow serradella and French serradella) against three reference species (Medicago sativa, M. polymorpha and Trifolium subterraneum ) in four temperature treatments (10/5, 15/10, 20/15 and 25/20°C; max/min). We also compared shoot relative growth rate and photosynthetic rate at 15/10°C (cool) and 23/18°C (warm). Cool temperatures (10/5, 15/10°C) did not slow germination rates for serradella relative to the reference species, but warm temperatures (20/15, 25/20°C) delayed emergence and reduced post-emergent shoot growth rates. Once established, Ornithopus spp. had similar mean photosynthetic rates and stomatal conductance at cool temperatures to the reference species. We conclude that, contrary to common perception, cool temperatures did not adversely influence germination, emergence, or early growth of Ornithopus spp. relative to the reference species.

Vector species, pasture legume host range, and impact on grain legumes of an Australian soybean dwarf virus isolate.

Soybean dwarf virus (SbDV; family Tombusviridae, genus Luteovirus, species Soybean dwarf virus) can cause damaging disease epidemics in cultivated plants of the family Fabaceae. The biological characteristics of SbDV isolate WA-8, including its vector species, host range, and impact on Australian grain legume cultivars, were investigated in a series of glasshouse experiments. Isolate WA-8 was classified as the YP strain, as it was transmitted by Acyrthosiphon pisum (pea aphid) and Myzus persicae (green peach aphid) and infected known strain indicator species. Of the 18 pasture legume species inoculated with SbDV, 12 were SbDV hosts, including eight that had not been identified previously as hosts. When inoculated with SbDV, field pea (Pisum sativum), faba bean (Vicia faba), lentil (Lens culinaris), and narrow-leafed lupin cv. Jurien were the most susceptible (70 to 100% plant infection rates), and albus lupin (Lupinus albus), chickpea (Cicer arietinum), and narrow-leafed lupin cv. Mandelup were less susceptible (20 to 70%). Over the course of three experiments, chickpea was the most sensitive to infection, with a > 97% reduction in dry above-ground biomass (AGB) and a 100% reduction in seed yield. Field pea cv. Gunyah, faba bean, and lentil were also sensitive, with a 36 to 61% reduction in AGB. Field pea cv. Kaspa was relatively tolerant, with no significant reduction in AGB or seed yield. The information generated under glasshouse conditions in this study provides important clues for understanding SbDV epidemiology and suggests that it has the potential to cause damage to Australian grain legume crops in the field, especially if climate change facilitates its spread.

Sheep grazing

Context An accession of the annual legume Trigonella balansae Boiss. & Reuter. has been selected for commercial release in Australia. Aims As part of a duty-of-care assessment, we tested the hypothesis that sheep grazing the trigonella accession will have liveweight, condition scores and wool production similar to those of sheep grazing two widely adopted annual legumes, subterranean clover (subclover, Trifolium subterraneum L. cv. Dalkeith) and French serradella (Ornithopus sativus Brot. cv. Erica). We also hypothesised that sheep grazing the three legumes will have similar meat quality and health, as indicated by blood plasma panel analysis. Methods Wethers (n = 6) grazed plots (n = 4) of three pasture species. Liveweight, condition scores and wool growth were measured, and a subset of animals were subject to blood sampling to assess health. Consumer sensory taste analysis was used to assess meat eating quality from two sheep per plot. Forage biomass, dry-matter digestibility, crude protein, fibre, mineral content and isoflavones were measured across the plant’s lifecycle. Key results There were no significant differences in liveweight, wool growth, wool yield or condition score that were associated with pasture species during the grazing period. There were differences in dry-matter digestibility, minerals and crude protein content of the pastures over time. As trigonella matured, it did not meet the minimum sulfur, phosphorus, manganese, molybdenum and copper requirements for mature sheep. We found some differences in indications of animal health; however, there were no significant systematic detrimental differences between sheep grazing trigonella and the other two species. In total, 2 of 24 individual sheep grazing trigonella had more than two plasma indicators of liver damage. There were no differences in meat tenderness, juiciness, flavour and overall consumer acceptability. Conclusions The data supported the hypotheses. Under the conditions of this experiment, the pasture legumes had the same relative feeding value. Some care must be taken in interpreting the outcome as the trigonellacomprised only 18% of the dry matter on offer at the termination of grazing. Implications Results of this study will be considered during the commercialisation process for T. balansae.

Development of methods to overcome physiological seed dormancy of temperate annual pasture legumes to assist speed breeding

Context and aims Freshly harvested seeds of temperate annual pasture legume species have physiological dormancy (PD), which delays the growth of the next generation and is thus an impediment to speed breeding. The aim of this study was to develop a method or methods of PD breaking that can achieve high germination (≥90%) within 5 days of picking freshly harvested seed. Methods In a series of experiments, PD breaking methods by themselves and in combination were tested on burr medic (Medicago polymorpha). The most promising methods were then tested on other annual medic species (Medicago spp.), subterranean clover (Trifolium subterraneum), and alternative species from six genera. Key results The successful PD breaking method involved drying pods overnight at 45°C, extracting and scarifying seed, placing seed on filter paper in a Petri dish along with non-dormant seed, imbibing seed with 4 μM benzylaminopurine, sealing the Petri dish, and incubating in the dark at 15°C. Highly dormant genotypes required the additional treatment of removing the testa. Conclusions We have developed an effective way of breaking seed PD in the 11 pasture legumes species from the seven genera tested. The rapid breaking of seed PD will assist speed breeding of annual pasture legumes, making it less laborious and time-bound than currently used methods. Implications The PD breaking methods are expected to assist basic science studies of annual pasture legume species and may be applicable to other species and genera.

Leaf formononetin content of Trifolium subterraneum increases in response to waterlogging but its proportion of total isoflavones is little changed.

The isoflavone formononetin (F) impacts livestock fertility and cultivars of the pasture legume Trifolium subterraneum L. (subclover) have been selected for F levels ≤0.2% of leaf dry weight. However, the impact of waterlogging (WL) on isoflavones is little studied. We investigated the response of isoflavones, biochanin A (BA), genistein (G) and F, to WL for: (1) Yarloop (high F) and eight low F cultivars each from subspecies subterraneum , brachycalycinum and yanninicum (Experiment 1); and (2) four cultivars and 12 ecotypes of ssp. yanninicum (Experiment 2). WL impacted F: estimated means increased from 0.19% (control) to 0.31% (WL) in Experiment 1 and from 0.61% to 0.97% in Experiment 2. Isoflavones under WL were highly heritable, particularly F (H 2 =95%). The proportions of BA, G and F were little changed by WL, with strong positive correlations between free-drained and waterlogged treatments. Isoflavone contents were not related to WL tolerance, as assessed by shoot relative growth rate. In conclusion, isoflavones varied among genotypes and increased with WL, but the proportion of individual isoflavones in each genotype was stable. High F under WL was unrelated with genotype tolerance to WL. Instead, it was a consequence of inherently high F for that particular genotype.

PRODUCTIVITY OF MELILOT (MELILOTUS OFFICINALIS (L.)) IN THE CONDITIONS OF RICE CROP ROTATION UNDER THE KYZYLORDA REGION

In the unfavorable environmental conditions of the Kyzylorda region, associated primarily with water scarcity, salinization and soil degradation, measures are needed for the cultivation of agricultural land and reproduction of soil fertility, associated with phyto-reclamation, the complex use of organic and mineral fertilizers, cultivation and introduction of salt-resistant crops, in particular legumes of perennial grasses, which, undoubtedly, it will become the basis for optimal functioning of agroecosystems, stable development of crop production diversification in order to obtain high-quality agricultural products. Melilotus, being an excellent pasture legume plant for restoring vegetation cover of saline soils, will make it possible to obtain high yields of off-season pasture production in territories that are currently unproductive.The article presents the results of studies to determine the effect of organomineral fertilizers on the yield and productivity elements of the clover. It was found that of the various studied norms of organomineral fertilizers, applying phosphorus fertilizers at a dose of P60 is the most effective, providing a stable and reliable increase in crop productivity by 53.5%. And the introduction of organomineral fertilizer "manure 15 t / ha + P60", where the highest yield of hay was 87.7 c / ha, the authors consider it ineffective, since the yield difference between them (2.2 c / ha) is insignificant, which is lower than the value of LSD05 = 4.7 c / ha. Variants of phosphorus fertilizers and a combination of manure of 15 t/ha with P60 had a significant impact on the quality and nutritional value of the melilot feed, where the protein content in the 1st year of the melilot life increased to 280.2 and 302.4 kg/ha, and in the 2nd year of life to 591.9 and 608.4 kg/ha.

Strawberry clover (Trifolium fragiferum): current status and future role in Australian agriculture

Strawberry clover (Trifolium fragiferum L.) is periodically raised as an alternative perennial pasture legume for temperate regions of Australia. Its tolerance of waterlogging is widely known, yet its ability to persist through periods of soil moisture deficit is often understated. Other desirable characteristics include its stoloniferous growth habit and tolerance of mildly saline conditions. Only four strawberry clover cultivars have been registered in Australia, and the most popular, cv. Palestine, is a direct introduction, released in 1938 and first certified in 1951. Furthermore, strawberry clover’s distribution has largely been confined to niche environments, particularly waterlogged and saline areas. This paper reviews the taxonomy and breeding system, morphology, distribution and ecology, and subsequent transfer of strawberry clover to Australia. It reviews and maps the suitability of strawberry clover for perennial pasture systems in the medium–-high rainfall and irrigated temperate zones of Australia, with reference to future climates. The paper also highlights the breeding focus, commercialisation and marketing required to supersede cv. Palestine and lists the germplasm available in the Australian Pastures Genebank, with origins. We conclude that, although strawberry clover is unlikely to become a dominant perennial pasture legume species in Australia, it could be used in a wider range of environments than just those affected by salinity and/or waterlogging stress.

Light competition is the key factor determining spatio-temporal variability in legume proportion within Marandu palisadegrass–forage peanut mixed pastures

Context Understanding ecology in grass–legume pastures can help support strategies aimed at maintaining canopy stability in terms of botanical composition. Aims This 2-year study evaluated spatial variability, focusing on plant structural characteristics in a Marandu palisadegrass [Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster cv. Marandu]–forage peanut (Arachis pintoi Krapov. and W.C. Greg. cv. BRS Mandobi) mixed canopy under grazing in continuous stocking management. Methods The pasture was managed with canopy height of 20–25 cm. The experimental area had a permanent sample grid containing 50 pre-established and georeferenced plots. Principal component analysis was performed, and spatial dependence structure of the first principal component and structural variables were separately characterised by geostatistical analysis. Key results There was spatial dependence of the structural characteristics, with marked spatial heterogeneity in the distribution of all variables. Taller grass canopies caused competition for light between species, reducing legume contribution and inducing more erect forage peanut growth habit. Conversely, in areas with lower grass canopy height, forage peanut botanical composition increased to up to 70%, as it propagated more effectively by stoloniferous propagation. Conclusions The canopy structure spatial variability of a Marandu palisadegrass–forage peanut mixed pasture determines the overall average pasture grass/legume proportion. In regions with taller canopies, Marandu palisadegrass was favoured, while in areas with shorter canopy, forage peanut proportion was promoted. Satisfactory legume proportions can be reached in the canopy despite areas with reduced legume contribution. Implications Our findings using geostatistical techniques facilitate the development of useful and innovative tools allowing better comprehension for the management of mixed pastures.

Antioxidant and functional attributes of maritime legume pastures of southwest India

Antioxidant and functional attributes of maritime legume pastures of southwest India

Evaluation of the productivity and feed value of Wondergraze and Redlands leucaena cultivars under grazing

Context Leucaena leucocephala (leucaena) is a leguminous shrub used for beef grazing in low-rainfall regions (<600–700 mm). Newer cultivars have the potential to extend adoption of the species to higher rainfall (>600–700 mm), frost-free areas of Australia. Aim We compared productivity, nutritional value and animal performance of two leucaena cultivars, new psyllid-resistant Redlands and the 2010-released Wondergraze, under continuous grazing management in a higher rainfall environment. Methods Growing steers were allocated to replicated established stands of Wondergraze or Redlands with inter-row mixed grass–legume pasture from January to July 2021. Pasture and leucaena were characterised for biomass and nutritive characteristics. Botanical composition was measured. Liveweight gain, rumen fermentation, and leucaena mimosine breakdown products were measured in grazing steers. Key results At the beginning of the study, leucaena edible biomass was similar for both cultivars (P > 0.05), but at subsequent samplings, biomass of Redlands was lower than of Wondergraze (P < 0.01). Biomass of both cultivars declined rapidly over the grazing period. Pasture biomass increased between February and July and was significantly higher in Wondergraze paddocks (P < 0.05). Animal performance was not significantly different between cultivar treatments, averaging 0.8 kg/day, but declined over time. Patterns of mimosine conversion to DHP isomers and their conjugation were similar for the two cultivars, suggesting that effectiveness of detoxification did not differ between them. Conclusion The results demonstrate that leucaena can sustain high levels of animal performance when included in tropical grass pastures in a higher rainfall environment if present in a sufficient quantity (>2 t leucaena edible dry matter/ha established leucaena). Implications Grazing leucaena–grass pastures is an effective means of increasing animal productivity in parts of subtropical Australia. However, managing grass and/or leucaena growth to match animal requirements can be challenging.

KAPASITAS TAMPUNG DAN LEGUMINOSA PADANG PENGGEMBALAAN DIKECAMATAN BULA KABUPATEN SERAM BAGIAN TIMUR

Background:This study aims to determine the botanical composition of forages and legumes and the capacity of livestock in grazing fields in Bula sub-district, East Seram Regency. Research methods:This research was conducted in May 2009 with research locations in 2 villages, Jembatan Basa and Bula villages and using a survey method conducted in the grasslands. Determination of sample villages and grazing locations based on purposive sampling based on village area and number of ruminants. This method uses dry weigh rank to determine the botanical composition of forage by using cluster sampling, while in measuring the capacity of the capacity is measured based on the formula voisin (Y-1) S = r. Results :The study showed the botanical composition as follows: Pangola grass (Digitaria decumbens) 22.36 percent, donated pasture. Leguminosa found in Bula Sub-district, East Seram Regency, Arachis Nuts (Arachis glabarata) 5.37 percent, Asu beans (Kalopogonium mucunoides) 4.11 percent. The results of the study showed that the carrying capacity (KT) for ruminants in Bula District was 1.39 ha/UT/year or 0.58 UT/ha/year. Conclusion: The botanical composition of legumes in pastures in Bula sub-district does not meet the 9.84 percent standard, besides that there are tree legumes such as gamal (Gliisida sepium), and Chinese petai (Lamtorogun).

Phytoestrogens: A Review of Their Impacts on Reproductive Physiology and Other Effects upon Grazing Livestock.

Simple SummaryPhytoestrogens are secondary plant metabolites that play a role in plant defense, and when ingested by livestock have numerous functions related to reproduction, metabolism, immunological functions and livestock growth and performance. Phytoestrogens are found across various plant species, with the most biologically active of these, isoflavones and coumestans, abundant in legume species. Understanding the overall potential health and reproductive effects that may occur in livestock grazing phytoestrogenic pastures is essential to mitigate any potential risks attributed to fertility loss or to introduce proactive management strategies to aid in improving growth and development. A review of their interactions with livestock systems will provide updated information for the agricultural and veterinary industries.Legume crops and pastures have a high economic value in Australia. However, legume species commonly used for grazing enterprises have been identified to produce high concentrations of phytoestrogens. These compounds are heterocyclic phenolic, and are similar in structure to the mammalian estrogen, 17β-estradiol. The biological activity of the various phytoestrogen types; isoflavones, lignans and coumestans, are species-specific, although at concentrations of 25 mg/kg of dry matter each of the phytoestrogen types affect reproductive functions in grazing livestock. The impacts upon fertility in grazing livestock such as cattle and sheep, vary greatly over length of exposure time, age and health of animal and the stress stimuli the plant is exposed to. More recently, research into the other effects that phytoestrogens may have upon metabolism, immune capacity and growth and performance of grazing livestock has been conducted. Potential new benefits for using these phytoestrogens, such as daidzein and genistein, have been identified by observing the stimulation of production in lymphocytes and other antibody cells. Numerous isoflavones have also been recognized to promote protein synthesis, increase the lean meat ratio, and increase weight gain in cattle and sheep. In Australia, the high economic value of legumes as pasture crops in sheep and cattle production enterprises requires proactive management strategies to mitigate risk associated with potential loss of fertility associated with inclusion of pasture legumes as forages for grazing livestock.

Feedlot growth performance and carcass characteristics of steers backgrounded on buffel grass or buffel-Desmanthus mixed pastures.

Feedlot performance and carcass characteristics of tropical beef steers backgrounded on buffel grass (Cenchrus ciliaris) only or buffel grass oversown with desmanthus (Desmanthus spp. ; 11.5% initial sward botanical composition) were evaluated. It was hypothesized that tropical beef cattle steers backgrounded on buffel grass only or buffel grass oversown with desmanthus with similar backgrounding growth performance will not differ in feedlot growth performance and carcass quality. Three hundred and twelve Bos indicus × Bos taurus tropical composite steers, 20–23 months old and weighing 413 ± 24 kg, previously backgrounded on buffel grass only or buffel-desmanthus mixed pastures for 147 days were finished on a concentrate diet in the feedlot for 110 days before slaughter. Buffel–desmanthus backgrounded steers had a slightly higher average daily gain (ADG; 1.8 kg/day) than the buffel grass backgrounded steers that had 1.7 kg/day ADG (p < 0.01). However, the final live weight and dry matter intake were not different (p ≥ 0.59). All the carcass traits measured were not different (p ≥ 0.18). Only 4% buffel grass and 8% buffel-desmanthus backgrounded steers fell short of the Meat Standards Australia (MSA) index, a level that is within the 4–9% reported for cattle produced in Queensland and slaughtered between July 2019 and June 2020. These findings indicate that desmanthus can be used to background beef cattle in northern Australia vertosol soil regions, where there is a paucity of adapted pasture legumes, with no negative impact on feedlot performance and carcass quality. The hypothesis that tropical beef cattle steers backgrounded on buffel grass only pastures or buffel grass oversown with desmanthus with similar backgrounding growth performance will have similar feedlot growth performance and carcass quality was accepted.

Improved legume pastures increase economic value, resilience and sustainability of crop-livestock systems

CONTEXTWell-managed legume pastures play a crucial role in agricultural systems, contributing to strategies for the increasingly complex challenges of supplying meat and wool, improving soil fertility, increasing land use efficiency while minimising environmental impacts, and building system resilience. OBJECTIVEThis paper examines the potential for a range of improved annual legume pasture species to deliver multiple benefits such as extending the length of the growing the season and closing feed gaps, boosting crop yields and farm profits, and contributing to natural resource management. METHODSUsing MIDAS, a bioeconomic model of a crop-livestock farming system, we quantified the relative profitability and sustainability of five self-regenerating legume pasture scenarios − burr medic (Medicago polymorpha L.), bladder clover (Trifolium spumosum L.), French serradella (Ornithopus sativus L.), biserrula (Biserrula pelecinus L.) and common vetch (Vicia sativa L.) − against the baseline scenario of (mainly) subterranean clover (Trifolium subterraneum L.) for the medium-rainfall region of Western Australia. RESULTS AND CONCLUSIONSThe modelling indicated that profit gains of more than 25% were possible by using an improved self-regenerating legume option when compared to a subterranean clover-based pasture system. This could be achieved through greater utilisation of land under pastures and higher stocking rates while still maintaining a major cropping program. The whole-farm economic benefits of improved legume pastures resulted from land use adjustments to sustain more profitable cropping and livestock enterprises, and benefits were small at low stocking rates. The combination of additional feed at the start of the season and slower loss of energy values at the end of the season in the improved pasture scenarios was an important profit driver for the livestock enterprise. Other benefits included projected savings in nitrogen fertiliser for crops in rotation with the pasture, greater sheep carrying capacity, improved efficiencies in supplementary feed and labour costs per animal, lower groundwater recharge, and improved farm business resilience overall. Pastures with higher nutritional value could lead to reduced net emissions per DSE if they allow ruminants to reach finishing weight faster or improve reproductive efficiency. SIGNIFICANCEThis whole-farm study expands previous work by comparing a broad range of annual legume pasture species developed for the soils and climatic conditions of Western Australia. The general principles behind changes in land use revealed by the MIDAS modelling have wide application beyond this Australian region, confirming the potential role of well-managed legume pastures for achieving sustainable intensification of agricultural systems, while offering sufficient flexibility for grazing systems to cope with climate variability.