A remotely sensed pasture management technology, Pasture Growth Rate (PGR) has been developed by a research consortium of the Department of Agriculture Western Australia (DAWA), Commonwealth Scientific and Research Organisation (CSIRO), and Department of Land Information (DLI). A pilot study was funded by Australian Wool Innovation in 2003 to deliver the PGR information to a number of producers; four cooperative groups in the Great Southern and two groups in Dandaragan. Six producers from these groups were studied during the pasture growing season to determine how they used the technology and assess improvement in profitability, if any of their farming business. Key Findings • In all cases the use of PGR improved the profitability of the sheep enterprise.The increase in gross margin ranged from $23 to $334/per winter grazed hectare (WGHA). • The increased margin resulted from better utilisation of pasture, more effective feed budgeting and the introduction of new management techniques into the farming system. • The information on PGR provided timely information that was not discernible from observation of either the animals or pasture in the paddock until two to three weeks later. • The information on PGR improved confidence in decision making and helped reduce stress levels.
There is much existing knowledge about the factors that influence adoption of new practices in agriculture but few attempts have been made to construct predictive quantitative models of adoption for use by those planning agricultural research, development, extension and policy. ADOPT (Adoption and Diffusion Outcome Prediction Tool) is the result of such an attempt, providing predictions of a practice's likely rate and peak level of adoption as well as estimating the importance of various factors influencing adoption. It employs a conceptual framework that incorporates a range of variables, including variables related to economics, risk, environmental outcomes, farmer networks, characteristics of the farm and the farmer, and the ease and convenience of the new practice. The ability to learn about the relative advantage of the practice, as influenced by characteristics of both the practice and the potential adopters, plays a central role. Users of ADOPT respond to 22 questions related to: a) characteristics of the practice that influence its relative advantage, b) characteristics of the population influencing their perceptions of the relative advantage of the practice, c) characteristics of the practice influencing the ease and speed of learning about it, and d) characteristics of the potential adopters that influence their ability to learn about the practice. ADOPT provides a prediction of the diffusion curve of the practice and sensitivity analyses of the factors influencing the speed and peak level of adoption. In this paper the model is described and its ability to predict the diffusion of agricultural practices is demonstrated using examples of new crop types, new cropping technology and grazing options. As well as providing predictions, ADOPT is designed to increase the conceptual understanding and consideration of the adoption process by those involved in agricultural research, development, extension and policy.
Despite their ecological, economic and social importance, grasslands in areas with Mediterranean climates continue to receive limited scientific, political and media attention. The main objectives of this review are to compare and contrast dryland grasslands in the Old World' regions of the Mediterranean basin (southern Europe, western Asia and North Africa) with those of New World' regions with Mediterranean climates (Australia and Chile) and to identify common research priorities. The common characteristics and differences in climate, soils, native vegetation, importance of the livestock sector and the socio-economic background for the different Mediterranean environments are examined. Past trends and the current status of temporary and permanent Mediterranean grasslands are also described. Some common issues between these regions are as follows: (i) adaptation to climate change; (ii) increasing persistence and drought survival of both annual and perennial species; (iii) the important role of forage legumes; (iv) maintaining grassland plant diversity; and (v) improved ecosystem services, such as carbon sequestration, control of soil erosion and wildfires, and preservation of both wild and domestic biodiversity. The favourable climate in these regions, which allows year-round grazing and the growth of legumes, should be exploited to improve the sustainability of grassland-based, extensive farming systems and the quality of their animal products, while at the same time improving ecosystem services. The decreasing support for grassland research and development programmes requires increased international scientific and technical cooperation among the few institutions operating in the different Mediterranean-climate areas of the World to provide innovative and sustainable solutions to farmers.
This study examined how sheep develop a learned aversion to the annual legume biserrula (Biserrula pelecinus L.). Merino sheep were grazed on paddocks sown with either (i) biserrula, (ii) biserrula+ryegrass (Lolium rigidum Gaud.), (iii) crimson clover (Trifolium incarnatum L.), (iv) crimson clover+ryegrass or (v) ryegrass, for 4weeks. Relative preference (Chesson-Manly selection index) was determined by offering randomly ordered monoculture plots of the three forage species. The groups of sheep were then combined into a single group and grazed a paddock containing a monoculture sward of each plant type for 5d. Relative preference of sheep was tested again after the completion of the combined grazing. The experiment was repeated at three stages of plant phenology: vegetative, reproductive and senesced. Relative preference for biserrula was lower in sheep that had grazed the paddock sown with only biserrula compared with sheep that grazed a combination of biserrula+ryegrass, at both the vegetative (; -011 vs. 032) and reproductive (; 018 vs. 063) stages. At each stage of phenology, when groups were combined and grazed together, preference for biserrula became uniform. This supported the hypothesis that sheep develop an aversion to biserrula when they graze a pasture containing biserrula. However, we concluded that the familiarity of sheep with biserrula did not result in low relative preference; rather, the aversion was more likely a response to the high proportion of this plant in their diet. Social facilitation may have enabled sheep to overcome rapidly the food aversion.
Tedera (Bituminaria bituminosa C.H. Stirton var. albomarginata and var. crassiuscula) has been identified as one of the most productive and drought-tolerant species of herbaceous perennial legumes based on 6 years of field evaluation in Western Australia in areas with Mediterranean climate and annual rainfall ranging from 200 to 600 mm. Importantly, tedera demonstrated broad adaptation to diverse soils, and some accessions have shown moderate levels of tolerance to waterlogging and salinity. Tedera exhibits minimal leaf shedding during summer and autumn. Economic modelling strongly suggests that giving livestock access to green tedera in summer and autumn will dramatically increase farm profit by reducing supplementary feeding. The breeding program (2006–12) evaluated the available genetic diversity of tedera for its field performance in seven nurseries with 6498 spaced plants in total covering a wide variation in rainfall, soils and seasons. Best overall plants were selected using a multivariate selection index generated with best linear unbiased predictors (BLUPs) of dry matter cuts and leaf retention traits. The breeding program also evaluated tedera for grazing tolerance, grazing preference by livestock, waterlogging tolerance, seed production, cold tolerance, disease susceptibility and presence of secondary compounds. Tedera is a diploid, self-pollinated species. Therefore, 28 elite parents were hand-crossed in several combinations to combine outstanding attributes of parents; F1 hybrids were confirmed with the aid of highly polymorphic, simple sequence repeat markers. The F1s were progressed to F4s by single-seed descent breeding. Elite parent plants were selfed for two generations to be progressed in the breeding program without hybridisation. Over time, selections from the crossing and selfing program will deliver cultivars of three ideotypes: (i) drought-tolerant, (ii) cold- and drought-tolerant, (iii) waterlogging- and drought-tolerant.
Dr Clive Francis is amongst a small group of scientists whose efforts have changed the face of Australian agriculture. This special issue of Crop & Pasture Science highlights his broadranging impact delivered through the pasture cultivars he bred, the knowledge that he generated and the influence that he had on peers and policy makers. His cultivars of subterranean clover are still grown on many millions of hectares across southern Australia and his efforts were pivotal in generating momentum for creative research on a wide array of crop and pasture legumes, particularly the collection, evaluation and preservation of genetic resources for use in current and future breeding initiatives.
The south-west of Western Australia has experienced a declining trend in annual rainfall and gradual warming over the last 30 years. The distribution of rainfall has also changed, with lower autumn rainfall, patchy breaks to the season, and shorter springs. This has important implications for the productivity of legume pastures in the region, which is dominated by annual species, particularly subterranean clover (Trifolium subterraneum L.), annual medics (Medicago spp.), serradella (Ornithopus spp.), and biserrula (Biserrula pelecinus L.). For annual pasture legumes, appropriate patterns of seed softening and germination behaviour, efficiency of phosphorus and potassium uptake, responses to elevated levels of atmospheric CO2, and drought resistance of seedlings and mature plants will assume increasing importance. While these traits can be targeted in pasture breeding programs, it will also be important to exploit farming system opportunities to optimise the annual legume component of the feed base. These opportunities may take the form of incorporating strategic shrub reserves and grazing crops to allow for pasture deferment in autumn–winter. Perennial forages may become more important in this context, as discussed in terms of the development of the perennial legume tedera (Bituminaria bituminosa var. albomarginata C.H. Stirton).
Tedera (Bituminaria bituminosa C.H.Stirt var. albomarginata) is a drought tolerant perennial legume originating in the Canary Islands. This study evaluates the potential role and value of tedera in dryland mixed crop and sheep production systems in southern Australia. Regional variants of the bio-economic model MIDAS are used to assess tedera in farming systems at two locations. The analysis considers the quantity and quality of feed produced by tedera, the ability of other forages to complement or substitute for tedera and its impact on meat versus wool-producing sheep flocks. The results indicate that tedera offers the potential to increase farm profits by up to 26% and be grown on ~28% of a low rainfall mixed enterprise farm. On a high rainfall mixed enterprise farm tedera may boost profit by up to 58% and be grown on ~75% of the farm. The increase in profit is attributable to savings in supplementary feed and higher stocking rates.
A wealth of evidence exists about the adoption of new practices and technologies in agriculture but there does not appear to have been any attempt to simplify this vast body of research knowledge into a model to make quantitative predictions across a broad range of contexts. This is despite increasing demand from research, development and extension agencies for estimates of likely extent of adoption and the likely timeframes for project impacts. This paper reports on the reasoning underpinning the development of ADOPT (Adoption and Diffusion Outcome Prediction Tool). The tool has been designed to: 1) predict an innovation‘s likely peak extent of adoption and likely time for reaching that peak; 2) encourage users to consider the influence of a structured set of factors affecting adoption; and 3) engage R, D & E managers and practitioners by making adoptability knowledge and considerations more transparent and understandable. The tool is structured around four aspects of adoption: 1) characteristics of the innovation, 2) characteristics of the population, 3) actual advantage of using the innovation, and 4) learning of the actual advantage of the innovation. The conceptual framework used for developing ADOPT is described.
Pasture-cropping is a novel approach to increasing the area of perennial forages in mixed livestock and cropping systems. It involves planting annual cereals directly into a living perennial pasture. There is interest in using subtropical grasses for pasture-cropping as they are winter dormant and their growth profile is complementary with winter crops. The ability of subtropical grasses to maintain feed quality in summer is likely to be an important attribute. However, a wide range of factors can affect the uptake of such systems. This paper evaluates the farm-system economics of subtropical grasses and pasture-cropping. The research question is: what factors affect the profitability of a new technology such as (1) subtropical grass and (2) subtropical grass that is pasture-cropped. The analysis uses the MIDAS model of a central wheatbelt farm in Western Australia. The results suggest the profitability and adoption of subtropical grasses is likely to be strongly influenced by the mix of soil types present on the farm; the feed quality of the subtropical grass; whether the production emphasis of the farm is for grazing or cropping, and the level of production in summer and early autumn. The same factors are relevant to pasture-cropping, with the addition of yield penalties due to competition between the arable crop and the host perennial. The results were less sensitive to changes in the winter production of subtropical grass. Pasture-cropping was more profitable and likely to involve a larger area of the farm when a meat rather than a wool-dominant sheep system was present. However, there was little difference between the meat and wool flocks in their sensitivity to other factors in this analysis.
In low rainfall wheatbelt regions of southern Australia the proportion of land occupied by annual legumebased pastures is low compared to adjacent areas receiving higher rainfall. A prerequisite for legume pasture introduction to these areas is the availability of a cultivar which will persist in the prevailing farming system. For many soils in low rainfall areas no such cultivar exists. Even where well adapted cultivars become available, farmers must be convinced that the introduction of the pasture legume can be achieved at low economic risk and that the resulting system will have profit advantages over alternative land uses.
We hypothesised that the preference of sheep among a wide range of annual legumes at successive stages of plant phenology would be related to laboratory measurements of the chemical composition of the forage. We tested this by examining the relative preferences of sheep among 20 genotypes of annual plants at three phenological stages of plant growth using the Chesson–Manly selection index. Plant material was collected for laboratory analyses at each phenological stage and samples were analysed for nitrogen, sulfur, neutral detergent fibre, acid detergent fibre, in vitro digestibility and water soluble carbohydrates. Sheep differed in relative preference among the plant genotypes within and between each of the three phenological stages. Vegetative characteristics that were correlated with relative preference also differed with plant phenology. Measured characteristics of the plant material explained an increasing proportion of the variance in relative preference with successive phenological stages (4.8, 51.1 and 60.9% at the vegetative, reproductive and senesced stages; P < 0.001). The relative preference of the sheep depended on the overall quality of the vegetation. When the quality of the vegetation was high, relative preference did not correlate well with measured nutritive characteristics. However, when the vegetation was of low quality, sheep selected plants with characteristics associated with higher nutritive value. We conclude that sheep adopt different foraging strategies in response to changing vegetation characteristics and increase their preference for plants that increase their intake of digestible dry matter as the sward matures.
Perennial wheat could improve grain production systems in Australia by rectifying many environmental problems such as hydrological imbalance, nutrient losses, soil erosion, and declining soil carbon and soil health. There are also potential direct production benefits from reduced external inputs, providing extra grazing for livestock in mixed farming systems, as well as benefits for whole-farm management which may offset lower grain yields. In addition to universal issues of domestication and breeding of perennial wheat, specific challenges for perennial wheat in Australia's dryland systems will include tolerance of water deficit and poor soil environments, and the risks of hosting foliar pathogens over summer. Temperate perennial forage grasses could indicate the potential distribution and traits required in perennial wheat adapted to more arid environments (e.g. summer dormancy). Several Australian native and exotic perennial relatives of wheat could also provide sources of disease resistance, and tolerance of soil acidity, drought, salinity and waterlogging. Still, several farming systems could accommodate perennial wheat with inconsistent persistence in some environments. While developing perennial wheat will be challenging, there is significant opportunity in Australia for perennial wheat to diversify current cropping options. The risks may be minimised by staged investment and interim products with some immediate applications could be produced along the way.
Perennial legumes in the Dorycnium genus may have potential as forage plants that could reduce the seasonality of feed production and improve the sustainability of agricultural systems. However, Dorycnium species are not currently used commercially and little is known about their agronomic characteristics. This review covers the current knowledge on Dorycnium distribution, taxonomy and the agronomic performance of Dorycnium hirsutum, Dorycnium rectum and Dorycnium pentaphyllum, including adaptation, establishment, biomass production, water use, grazing management and nitrogen fixation, along with considerations for animal production. Dorycnium originate from temperate Europe and the Mediterranean basin and may be suitable for other regions with similar climatic conditions. Little data exist on the climatic and edaphic conditions to which Dorycnium species are best adapted. Current evidence suggests that D. hirsutum is widely adapted and might be suitable as a forage plant for acid soils in drier and frost-prone agricultural regions. D. hirsutum also persists well in low rainfall environments ( down to 300 mm mean annual rainfall), can produce up to 21 t dry matter(DM)/ha in its first 3 years and, by utilising extra water compared with annual pastures, can reduce water leakage below the root zone, thereby slowing development of dryland salinity. The use of D. rectum would be limited to high rainfall or water-accumulating sites. D. pentaphyllum is a diverse species, yet available material appears to be less productive but has better forage quality than D. hirsutum. Currently, establishment reliability and/or forage digestibility are major limitations of the tested Dorycnium species that restrict their potential role and challenge the feasibility of their future use. Breeding may overcome or minimise these limitations and improved agronomic management might also enhance their usefulness. However, current collected genetic resources of Dorycnium are very limited and targeted collections would be needed to yield better adapted germplasm. Breeding to reduce the high levels of condensed tannins (> 13% of DM) to moderate concentrations in Dorycnium might improve forage digestibility and could have positive implications for animal performance and health. Despite the poor digestibility of some Dorycnium species (< 60% DM digestibility), these plants may still play a significant role as drought forage to provide feed when other forage sources are in limited supply. Further research is required to quantify the potential of Dorycnium species for commercial release and to determine how these plants should be best managed and integrated into livestock and mixed cropping systems.
A rapid (7 day) solution-based screening test was developed using 15 annual Medicago cultivars and one M. sativa. Based on a relative root regrowth after exposures to aluminium (Al), Zodiac (M. murex), Orion (M. sphaerocarpos) and the M. polymorha cultivars Santiago, Cavalier and Serena had the greatest Al tolerance. Herald (M. littoralis) and Rivoli (M. tornata) were most sensitive. Ranking for Al tolerance from the solution culture correlated well (r = 0.80) with ranking for tolerance of the 16 genotypes grown in an acidic soil (unlimed pHCa 4.1). We screened 17 Australian populations of lucerne (M. sativa) using a 24 h ‘pulse’ of 75 µmol/L Al, and a three day ‘recovery’ of 10 µmol/L Al. We identified and recovered plants with a root regrowth of ≥5 mm in all 17 populations with selection intensities of 2 to 4%. Four of these selected populations (Aurora, UQL-1, A513 and TO2-011) were polycrossed within each population to produce four populations of seed from the cycle 1 selections. The length of root regrowth under Al stress was improved for all four populations of cycle 1 selection (P ≤ 0.001; from 2.6 mm for the original populations to 6.3 mm for the cycle 1 selections). In a subsequent experiment the cycle 2 selections from Aurora, UQL-1 and TO2-011 had significantly greater root regrowth than both the cycle 1 selections (P ≤ 0.001; 8.3 cf. 6.6 mm) and the unselected populations (3.0 mm). The selections from TO2-011 appeared to have greater improvement in the average length of root regrowth after 2 cycles of selection. Selected germplasm was more tolerant than GAAT in our evaluation. Based on estimation of realised heritability, it seemed likely that higher selection intensities would give more rapid improvements in tolerance. Our studies have not investigated the physiological basis of any tolerance of Al which we observed.