ORCID Profile
0000-0002-3571-5618
Current Organisations
AgResearch Ltd
,
AgResearch Ltd Ruakura Research Centre
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Publisher: Wiley
Date: 10-2000
Publisher: Canadian Science Publishing
Date: 07-1996
DOI: 10.1139/B96-132
Abstract: Nine riverbank species were grown in a range of salinities to estimate salt tolerances. These tolerances, and others calculated from previous studies, are compared with the species’ distributions upstream–downstream and upshore–downshore on brackish riverbanks. Downstream and downshore limits could predict the salt tolerance of the species, together accounting for 64% of the variation. Upstream and upshore limits accounted for 58%, but the relation with upstream limits was not statistically significant. There was a continuous range of tolerances. Keywords: adaptation, brackish marsh, ecological distribution, estuary, river marsh, RGR, salinity tolerance.
Publisher: Informa UK Limited
Date: 20-11-2017
Publisher: Informa UK Limited
Date: 02-01-2014
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA04040
Abstract: This paper reports results from a large-scale field experiment conducted on a naturalised pasture at Carcoar, New South Wales, during the period 1997–2002. Here we describe the effect of pasture type and management on pasture productivity and composition, and discuss implications for long-term productivity. Four different pasture types (unfertilised naturalised, UN fertilised naturalised, FN fertilised introduced species, SP and fertilised chicory, CH) were each subjected to 2 management strategies (continuously grazed, CG and tactically grazed, TG). Stocking rate was set at a conservative level initially and then adjusted periodically based on ewe performance and minimum values of herbage mass (HM) in winter. TG involved a summer deferment when required and a lower stocking rate than on the CG treatment. CH was managed under a 4-paddock rotation. SP and CH also had 2.5 t/ha lime surface applied before introduced species being sod-sown. Available herbage mass tended to peak during spring and summer and was lowest in late autumn–early winter. Under CG, application of superphosphate to the naturalised pasture increased herbage mass by up to 60%, but most of the response came from annual grasses (mainly vulpia and soft brome), and subterranean clover during spring. Fertiliser initially increased the herbage mass of perennial grasses relative to the unfertilised continuously grazed control, but this component decreased over time. TG increased the perennial grass content. Annual grass herbage mass was greater where fertilised and continuously grazed, but over time declined where unfertilised and/or tactically managed. Legumes were a minor component of these pastures, but were higher where fertilised and lower where tactically grazed. Net pasture growth rate (NGR) varied with seasonal conditions, and was higher where fertiliser was applied. The data suggest that replanting perennial grasses is an effective process for increasing perenniality in this environment providing that it is economic. Further, the implementation of TG over summer has proved to be a useful approach for maintaining or increasing perennial content in existing pastures. However, there is a need to integrate TG with the timing of superphosphate application to maximise the effect on the perennial component and minimise dominance by annual species.
Publisher: Elsevier BV
Date: 03-2008
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA04041
Abstract: The main limitations for prime lamb production in the Central Tablelands of New South Wales are low availability of forage early in the growing season (late autumn–early winter) and low nutritive value in the summer. This paper describes the performance of a first-cross lamb breeding enterprise on 4 pasture types and 2 management systems over 4 years for the Central Tablelands region. The pastures studied comprised a traditional unfertilised naturalised pasture, a similar pasture fertilised with superphosphate, a sod-sown fertilised introduced perennial grass pasture and a sod-sown summer growing perennial, chicory (Cichorium intybus L.) pasture. Grazing management involved either continuous grazing or tactical grazing that combined a lower annual stocking rate with an optional summer rest to maintain perennial grass content above 50%. An additional area of chicory pasture was set aside for finishing lambs. Over the experiment stocking rates were increased each year as the pasture became established, with increases ranging from 1.5 ewes/ha for tactically grazed unfertilised natural pasture to 3.6 ewes/ha, for chicory and clover pasture. The feed quality v. quantity problem of summer and autumn was reaffirmed for each pasture type except chicory and the lamb enterprise appeared to be sufficiently adaptable to be promising. Ewes lambed in September and produced satisfactory lamb growth rates (about 280 g/day for twins) on the various pastures until weaning in late December. Thereafter, lamb growth rates declined as the pastures senesced, except chicory, reaffirming the feed quality v. quantity problem in summer and autumn of naturalised and sown grass pastures for producing lamb to heavyweight market specifications. Weaning liveweights (in the range of 32–40 kg) from grass-based pastures were high enough for only about 45% of the lambs to be sold as domestic trade lambs with the remainder as unfinished lambs. In contrast, the chicory and clover finishing pasture produced lamb growth rates of 125 g/day and quality large, lean lambs suitable for the export market. Vegetable matter in the late January shorn wool was insignificant and there was no significant effect of pasture on fleece weight, fibre diameter or staple strength. Position of break in staples of wool from chicory pastures differed from that of the other pasture types and warrants further study on time of shearing. It was concluded that a first cross lamb producing enterprise of suitable genetics was effective in producing trade and store lambs before pasture senescence, but the inclusion of a specialised pasture of summer growing chicory would create greater opportunities. In the unreliable summer rainfall region of the Central Tablelands, the area of chicory pasture needed to maintain lamb growth rates of g/day, estimated from these results, is around 10 lamb/ha of chicory.
Publisher: Oxford University Press (OUP)
Date: 07-1999
Publisher: Wiley
Date: 07-06-2013
Publisher: Springer Science and Business Media LLC
Date: 08-1995
DOI: 10.1007/BF00129253
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA04269
Abstract: Soil water, runoff amount and quality, pasture production and environmental data were measured for a pastoral prime lamb enterprise in the Central Tablelands of New South Wales from 1998 to 2002. There were 4 pasture treatments: fertilised and sown chicory (CH), fertilised and sown introduced pastures (SP), fertilised naturalised pastures (FN) and unfertilised naturalised pastures (UN). Two grazing management regimes, tactically grazed (TG) and continuously grazed (CG) were imposed on the SP, FN and UN treatments. The CH treatment was rotationally grazed. To compare pasture and grazing system water use, maximum soil water deficit values (SWDMax) were calculated from neutron moisture meter data. SWDMax was influenced by both environmental and management factors. Management factors that influenced SWDMax were herbage mass of perennials, degree of perenniality, and the perennial species present. Environmental factors accounted for % of the variation in SWDMax. Inclusion of management factors (perennial herbage mass of C3 and C4 species and percentage perennial herbage mass), accounted for an additional 16% of variation. While the influence of pasture management appears to be relatively small, importantly, management is the only avenue available to land managers for influencing SWDMax. The UNTG and all sown treatments, with greater perennial herbage mass or greater C4 herbage mass consistently produced the highest SWDMax. Runoff amount and quality data are presented for ground cover percentages which generally exceeded 80% for the experimental period. Runoff as a proportion of rain received during the experiment was %. Environmental factors explained 47% of variation in runoff, while pasture herbage mass and ground cover percentage explained an additional 2% of variation. Water quality was monitored on 3 treatments (SPTG, FNTG and UNCG) for total nitrogen (N), total phosphorus (P) and total suspended solids (TST) over a 6-month period. The mean values for total N and P were below the acceptable contaminant concentration for agricultural irrigation water. An important outcome of this research is the concept of a practical Targeted Water Management Plan (TWMP) which devises a framework for optimum water usage and productivity at a landscape scale.
Publisher: Wiley
Date: 08-1999
DOI: 10.2307/3237181
Publisher: Springer Science and Business Media LLC
Date: 02-03-2012
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/AR07112
Abstract: Nassella trichotoma (serrated tussock) is a hardy perennial grass weed that rapidly invades disturbed areas. Pasture competition is an important component of an integrated weed-management system for native pastures. This paper reports on a field experiment to ascertain the level of competition from native grasses for adult N. trichotoma plants. Native grasses prevented N. trichotoma plants from increasing in biomass and basal area when rotationally grazed or when grazing was removed and fertiliser was withheld. Smaller N. trichotoma plants ( mm2) were more likely to vary in size with very little change in larger plants. Flupropanate efficiently killed all N. trichotoma plants but caused considerable damage to perennial native species, resulting in an uncompetitive pasture dominated by broadleaf weeds.
Publisher: Springer Science and Business Media LLC
Date: 13-11-2012
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/AR07113
Abstract: Native perennial grass competition can substantially reduce the invasion of Nassella trichotoma (serrated tussock), a major perennial grass weed problem in south-eastern Australia. This paper reports on a field experiment that investigated the recruitment of N. trichotoma seedlings, and determined what level of native grass competition was needed to prevent establishment in the central-west of NSW. Grasslands that maintained t dry matter (DM)/ha and 100% ground cover (measured in spring) prevented N. trichotoma seedling recruitment. Relatively small amounts of perennial grass ( .5 t DM/ha measured in spring) resulted in mortality of N. trichotoma seedlings that had recruited earlier in the year, through the next summer. Flupropanate also markedly reduced native perennial grasses and substantially increased N. trichotoma seedling establishment 12 months after application. Rotational grazing to maintain adequate levels of DM was an important management tactic that prevented N. trichotoma establishment and survival.
Publisher: Wiley
Date: 06-1990
DOI: 10.2307/3235718
Publisher: Informa UK Limited
Date: 21-05-2015
Publisher: Elsevier BV
Date: 2010
Publisher: Informa UK Limited
Date: 28-02-2018
Publisher: Wiley
Date: 09-04-2003
Publisher: Oxford University Press (OUP)
Date: 26-07-2005
DOI: 10.1093/AOB/MCI230
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA04196
Abstract: There have been significant declines in the perennial grass (PG) content in native and sown pastures across temperate Australia. Not only has this reduced agricultural productivity, it has contributed to more serious degradation, such as loss of soil and bio ersity, decreasing water quality, and dryland salinity caused by rising watertables. Results from the Sustainable Grazing Systems Key Program (SGS) research undertaken at Carcoar on the Central Tablelands of New South Wales were reported by Michalk et al. (2003). This research indicated that grazing management tactics can be used to manipulate pasture composition, thereby changing animal production and water-use patterns. The main grazing tactic investigated was termed a summer grazing rest, where resting was imposed in late spring if PG composition was %. Reported in this present paper is an economic framework for valuing the long-term benefits of grazing management tactics. The framework involves the development of a bioeconomic modelling system that links a dynamic programming model with biophysical models for water and environmental processes, soil fertility, pasture growth, livestock energy requirements and the change in pasture species composition. The study concludes that long-term economic returns are improved by strategies, e.g. a summer rest, that lead to an increase in PG composition over time. The study also determined that environmental factors, such as deep drainage, runoff and soil loss, are reduced as perenniality is increased.
Publisher: Wiley
Date: 12-2006
Publisher: Wiley
Date: 12-2006
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/CP17154
Abstract: Growth responses of perennial ryegrass (Lolium perenne L.) diploid cv. Alto and a tetraploid breeding line of Alto infected with wild-type fungal endophyte to three types of stress were studied in a semi-controlled environment. The stresses imposed were: soil-moisture deficit (wilting point vs field capacity), severe defoliation (2.5 vs 6 cm cutting height), and root-feeding invertebrate infestation (nil vs 600 grass grubs (Costelytra zealandica) m–2). Stress treatments were applied simultaneously in a fully factorial design for 8 weeks followed by a 4-week recovery period. Total plant biomass was reduced to a similar extent for both ploidies by soil-moisture deficit (43% reduction), severe defoliation (31% reduction) and root-feeding invertebrates (13% reduction) at the end of the treatment period. At the end of the recovery period, feeding by grass grubs reduced root biomass by 34% and total plant biomass by 25% in the tetraploid cultivar, but there was no effect in the diploid cultivar. Although compensatory growth occurred during the recovery period, one or more aspects of plant growth (e.g. tillering, biomass) remained lower in previously stressed plants at the end of the recovery period. The lower tiller density and total biomass of the tetraploid, in combination with greater allocation of resources to shoot growth and greater susceptibility to root-feeding invertebrates, may compromise its persistence in the field.
Publisher: Wiley
Date: 04-1998
DOI: 10.2307/3237120
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA04039
Abstract: Temperate perennial grass-based pastures dominate the high rainfall zone of south-eastern Australia and support a major livestock production industry. This area has experienced a recent change in overall pasture condition, however, typified by a reduction in the abundance of perennial grasses and an increasingly prominent winter-annual grass weed component. Improving the condition and productivity of these pastures can be achieved by improved management but this requires better knowledge of the interactions between management options and pasture species composition and of the interaction between pasture vegetation and the complex effects of a heterogeneous landscape. This paper reports the results of an intensive survey of a 60-ha paddock that was designed to identify the species present, determine their patterns of distribution and examine the relationships between pasture vegetation and the environment. The survey of species present in late summer was supplemented by the identification of seedlings that later emerged from extracted soil cores and by soil physical and chemical analyses. Data were analysed using ordination and interpreted with GIS software so that topographic features could be considered. The most frequently identified taxa were Hypochaeris radicata, Austrodanthonia spp. and Bothriochloa spp. (in late summer) and Vulpia spp., Bromus molliformis and Trifolium subterraneum (winter-annual species). Austrodanthonia spp. were commonly found on the drier ridges and more acid soils with lower phosphate levels. These were also the areas dominated in spring by Vulpia spp. and were generally lower in plant species richness overall. The most species-rich areas occurred downslope where soil fertility was higher and less moisture stress was presumably experienced. The measured environmental factors explained a substantial proportion of the variation in the vegetation dataset, which underlined the importance of considering landscape effects in the management of typical tablelands pastures.
No related grants have been discovered for Warren King.