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.

The introduction of exotic pasture germplasm has formed the foundation of many Australian grazing systems. Scientists have searched the world for plants to improve the feedbase, amassing collections of diverse genetic material, creating genebanks that have made a large contribution to feedbase productivity. These genebanks contain a vast range of legumes, grasses, herbs and shrubs with growth habits ranging from small herbaceous plants to woody trees and life cycles from annuals to short- and long-term perennial plants. They have been collected from cool temperate to tropical climates and arid to high-rainfall zones. Hundreds of cultivars have been developed from material either collected by Australian plant breeders overseas or introduced from overseas genebanks. The collection of this germplasm has enabled plant breeders to extend the area of adaptation of species into climates, soils and systems previously considered marginal. The importance to Australian and world agriculture is increasing as plant breeders seek traits to meet the challenges of a changing climate and animal production systems. Furthermore, urbanisation, landscape degradation and political instability are making it increasingly difficult to collect pasture and forage germplasm from native grasslands in many countries. This emphasises the need to maintain and improve the capacity of the Australian Pastures Genebank (APG). The APG houses ~85 000 accessions and is a modern, online source of diversity for plant scientists around the world. This paper summarises the history of the founding genebank collections, their environment and farming systems focus, and the visionary and resourceful individuals that built them.

Species composition is limiting production in >65% of pastures in Tasmania, Australia—a situation not unique to Tasmania. There are many reasons for degradation and poor persistence of improved pastures, with species selection crucial. Selection currently relies on producers making an assessment based on experience, external advice from agronomists and seed merchants, and experimental trial data. This project sought to assess the benefit of using fine-scale soils data and long-term rainfall data to determine the suitability of pasture species at a farm level across >3 Mha of agricultural land in Tasmania. Suitability rules were developed for perennial ryegrass (Lolium perenne L.) and lucerne (Medicago sativa L.) involving growth responses to soil characteristics (pH, soil depth, electrical conductivity, drainage, and coarse fragments) and average annual rainfall. Suitability classes were defined as well suited, suitable, moderately suitable, and unsuitable, with additional subclasses to account for soil limitations that could be mitigated through management. Soil grids were generated using digital soil mapping techniques from ~6500 new and existing site data sources spread across Tasmania. Rainfall data from 539 Bureau of Meteorology rainfall-recording sites were modelled using regression kriging interpolation. Soil pH was found to be a major constraint on lucerne, with 61.3% of the land area having a pH <5.7. Ameliorating the soil with lime could reduce this constraint to 33.5% of the land area. Drainage was another major constraint on lucerne suitability, with 37.8% of land constrained by imperfectly or poorly drained soils. Improving drainage by installing surface or underground drains could reduce the affected area to 22.1%. The mapping showed that perennial ryegrass was constrained by soil pH, with 38.2% of land having a pH <5.5. However, liming could reduce this constraint to just 9.6%. Accurate identification of the likely constraints on pasture production and persistence before sowing and choice of appropriate species and management intervention will result in fewer failed sowings and greater productivity. The feasibility of expanding this approach is being assessed for a larger area of south-eastern Australia and across a wider range of pasture species.

This review examines the prospect of improving perennial legume adaptation to grazed mixed pasture swards across the higher-altitude regions of south-eastern Australia through improved management, particularly as it relates to soil fertility. The range of adapted perennial species available to farmers often remains limited to only one perennial forage legume species, white clover (Trifolium repens L.). Despite recent advances in cultivars for increased persistence in dryland environments, white clover remains sensitive to drought with its inherently shallow root system and limited capacity to restrict water loss from herbage. With few alternative species likely to become widely available in the foreseeable future, prospects for extending the boundaries of perennial legume adaptation likely rely on a dual approach of improving soil fertility and further genetic improvement in white clover. Improved soil fertility would focus on overcoming soil acidity and addressing nutrient deficiencies, particularly of phosphorus, potassium, boron and molybdenum, which tend to be more widespread in the target region. Addressing these soil constraints would alleviate periodic moisture stress by: (1) increased water availability through improved infiltration and soil hydraulic properties; (2) increased root growth to maximise exploration of the soil volume; and (3) better maintenance of plant cell structures to foster improved osmotic regulation. However, the extent to which white clover adaption may be extended remains an issue of further research. This review highlights an opportunity for further genetic improvement of white clover by focusing on improving the capacity to recover from periodic droughts through seedling regeneration. Further breeding efforts in white clover should examine the feasibility of selecting for hard seed characteristics more similar to the best-adapted subterranean clover (Trifolium subterraneum L.) cultivars across this region to promote ongoing seedling regeneration.

Over the last century, unexploded ordnances have been disposed of in marine shelf systems because of a lack of cost‐effective alternatives. Underwater unexploded ordnances have the potential to leak 2,4,6‐trinitrotoluene (TNT) and 1,3,5‐trinitro‐1,3,5‐triazine (RDX), commonly used chemical munitions, and contaminate local waters, biota, and sediments. The rate at which this contamination occurs in the environment is relatively unknown, and the cost‐ and time‐prohibitive nature of sampling across sites makes mapping difficult. In the present study we assessed the efficacy of ethylene‐vinyl acetate (EVA) for sampling relatively soluble munitions compounds over a range of environmental conditions (i.e., changes in temperature and salinity) and optimized the composition of the passive sampling polymer. The EVA sampler was able to successfully detect ambient concentrations of lingering munitions compounds from field sites containing unexploded ordnances. The sampler affinity for the munitions in terms of an EVA–water partition coefficient was greater than the standard octanol water values for each target compound. Partitioning of compounds onto EVA over the natural ranges of salinity did not change significantly, although uptake varied consistently and predictably with temperature. Increasing the vinyl acetate to ethylene ratio of the polymer corresponded to an increase in uptake capacity, consistent with enhanced dipole–dipole interactions between the munitions and the polymer. This sampler provides a cost‐effective means to map and track leakage of unexploded ordnances both spatially and temporally. Environ Toxicol Chem 2018;37:1990–1997. © 2018 SETAC

Examination of the partitioning of explosives onto sediment in marine environments is critical to predict the toxicological impacts of worldwide explosive-contaminated sites adjacent to estuaries, wetlands, and the coastal ocean. Marine sediments have been identified as sites of enhanced munitions removal, yet most studies addressing these interactions focus on soils and freshwater sediments. The present study measured the kinetics of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) sorption onto 2 marine sediments of varying grain sizes (silt vs sand) and organic carbon (OC) content. Abiotic sediment sorption tests were performed at 23 degrees C, 15 degrees C, and 4 degrees C by spiking TNT and RDX solutions directly into anaerobic sediment slurries. Marine sediments showed significantly higher compound uptake rates (0.30-0.80 h(-1)) than freshwater silt (0.0046-0.0065 h(-1)) for both compounds, probably because of lower compound solubilities and a higher pH in marine systems. Equilibrium partition constants are on the same order of magnitude for marine silt (1.1-2.0L kg(-1) sediment) and freshwater silt (1.4-3.1 L kg(-1) sediment) but lower for marine sand (0.72-0.92 L kg(-1) sediment). Total organic carbon content in marine sediments varied linearly with equilibrium partition constants for TNT and was moderately linear for RDX. Uptake rates and equilibrium constants of explosives are inversely correlated to temperature regardless of sediment type because of kinetic barriers associated with low temperatures. (C) 2015 SETAC

Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013, and models of energy balance between Pluto's surface and atmosphere, we find the preferred models are consistent with Pluto retaining a collisional atmosphere throughout its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N-2 ice cap at Pluto's north rotational pole. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license.

The bioconcentration factor (BCF) was measured for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in seven different marine species of varying trophic levels. Time series and concentration gradient treatments were used for water column and tissue concentrations of TNT, RDX, and their environmentally important derivatives 2-amino-4,6-dintrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT). BCF values ranged from 0.0031 to 484.5 mL g(-1) for TNT and 0.023 to 54.83 mL g(-1) for RDX. The use of log K ow value as an indicator was evaluated by adding marine data from this study to previously published data. For the munitions in this study, log K ow value was a good indicator in the marine environment. The initial uptake and elimination rates of TNT and RDX for Fucus vesiculosus were 1.79 and 0.24 h(-1) for TNT and 0.50 and 0.0035 h(-1) for RDX respectively. Biotransformation was observed in all biota for both TNT and RDX. Biotransformation of TNT favored 4-ADNT over 2-ADNT at ratios of 2:1 for F. vesiculosus and 3:1 for Mytilus edulis. Although RDX derivatives were measureable, the ratios of RDX derivatives were variable with no detectable trend. Previous approaches for measuring BCF in freshwater systems compare favorably with these experiments with marine biota, yet significant gaps on the ultimate fate of munitions within the biota exist that may be overcome with the use stable isotope-labeled munitions substrates.

Irrigated forage crops sown in autumn increase land utilisation compared to the common practice in Northern Tasmania of grazing crop stubbles over winter. However, there is little information on which crops best suit this short cropping phase prior to sowing an irrigated winter/spring crop such as poppies or green peas. The aim of this study was to evaluate a diverse range of forage species and varieties that provide the most valuable grazing over autumn and winter. Thirty four varieties of cereals, grasses, legumes and other broadleaf species were selected and dry matter production and nutritive value evaluated. There was significant variation in DM yields both between and within species. The highest cumulative total DM production for the season (5 – 5.5 t ha -1 ) was from annual ryegrass and cereals with winter habit. The main production difference between varieties was the timing of maximum growth. Spring varieties of cereals, canola and grain legumes showed rapid early growth but damage to growing points with removal of dry matter reduced subsequent regrowth. In contrast, there was minimal damage to slower growing winter cereals with more prostrate early growth. This work highlights the importance of species and variety selection when determining optimal feed production.

Grass weeds abundant in improved pastures For some people thistles, docks and capeweed may be the first things that come to mind when pasture weeds are mentioned. However, a recent survey of the composition of pasture in Tasmania has revealed that grass weeds may also have a large negative impact on the productivity of grazing industries. In late 2011 the Tasmanian Institute of Agriculture undertook an extensive survey of the State’s pastures. This study was conducted to provide a base line data set of the improved pasture resource and inform future direction of pasture research and extension. Over 800 pastures were assessed using a novel technique purposely designed to cover a large area but also be analysed at a regional scale. At each site the pasture was assessed visually by recording the percentage cover of each individual grass species in the pasture.

Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013 and models of energy balance between Pluto's surface and atmosphere, we conclude that Pluto's atmosphere does not collapse at any point in its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N2 ice cap at Pluto's north rotational pole.