Sustainable grazing systems for the Central Tablelands, New South Wales

2003 ◽  
Vol 43 (8) ◽  
pp. 861 ◽  
Author(s):  
D. L. Michalk ◽  
P. M. Dowling ◽  
D. R. Kemp ◽  
W. McG. King ◽  
I. J. Packer ◽  
...  

Pasture degradation is a major issue in the high rainfall zone (>600 mm) of temperate Australia. Characterised by a decline in the perennial grass component, this degradation is responsible for reduced livestock production and implicated in environmental problems, such as dryland salinity, through changed water-use patterns. This paper reports on a multi-disciplinary research program conducted at Carcoar in central New South Wales, one of 6 sites that comprised the Sustainable Grazing Systems National Experiment. The aim of the experiment was to develop more profitable and sustainable pasture systems by evaluating the impact of changes in the perennial grass component on animal production and water-use patterns. Tactical management strategies were evaluated on naturalised and sown perennial grass pastures and on chicory (Cichorium intybus), using a Merino ewe-based first cross lamb enterprise. Data presented showed that grazing deferment over summer, combined with reduced stocking rate, increased perenniality and reduced annual grass weeds compared with continuous grazing. Livestock performance, however, did not always follow trends in available perennial herbage mass. Naturalised and sown pastures were suitable for raising prime lambs, but only chicory had the capacity to finish lambs to market specification without supplementation. With respect to water-use patterns, sown perennial pastures were more successful than naturalised pastures in reducing leakage of water from the root zone, although this seemed to be related mostly to the abundance of the perennial grass in the pasture. From a sustainability perspective, continuously grazed pastures generated higher net cash flows, but had negative environmental impacts, whereas tactically grazed pastures had positive on- and off-farm impacts but lower net cash flows. The implications of these findings for incorporation into future management strategies for sustainable production in high rainfall environments are discussed.

2006 ◽  
Vol 46 (4) ◽  
pp. 495 ◽  
Author(s):  
R. E. Jones ◽  
P. M. Dowling ◽  
D. L. Michalk ◽  
W. McG. King

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 biodiversity, 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 <50%. 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.


1998 ◽  
Vol 40 (1) ◽  
pp. 53-67 ◽  
Author(s):  
Stephen R Gaze ◽  
Joost Brouwer ◽  
Lester P Simmonds ◽  
John Bromley

1986 ◽  
Vol 8 (2) ◽  
pp. 140 ◽  
Author(s):  
BH Downing

Examination of data on dietary preferences of sheep, goats and cattle suggests that different grazing systems are desirable for each of the three major woodland types (belah-rosewood, mulga, poplar box) examined. Competition for herbs, frequently palatable to all animal species, indicates that goats and sheep are unsuitable for joint use either in heavily wooded country or where annual herbaceous production is less than 200 kg-ha. Supplementary feeding, fire and judicious stocking are proposed as a strategy for inducing goats to eat a proportion of unpalatable shrubs. The literature provides little helpful information on how rangelands in the Western Division should be managed. No reports are given on comparisons of grazing systems, such as rotational grazing, rotational resting, and continuous grazing. No guidance is given on grazing after burning of the rangeland. Recommendations are generally against the use of goats for control of woody plants, whereas local observation shows this to be an apparently effective practice. The recommendations are mostly based on experimental procedures which, although suitable for detecting animal dietary preferences in the short term, are less appropriate for investigation of the effects of grazing on range condition in the long term. Some suggestions are made towards a different approach for: investigating the effects of grazing by sheep and goats on rangeland condition, and the economic implications of this in terms of animal production.


2009 ◽  
Vol 27 (5) ◽  
pp. 377-391 ◽  
Author(s):  
Leonard J. M. Githinji ◽  
Jacob H. Dane ◽  
Robert H. Walker

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 446 ◽  
Author(s):  
Hazel Farrell ◽  
Penelope Ajani ◽  
Shauna Murray ◽  
Phil Baker ◽  
Grant Webster ◽  
...  

An end-product market survey on biotoxins in commercial wild harvest shellfish (Plebidonax deltoides, Katelysia spp., Anadara granosa, Notocallista kingii) during three harvest seasons (2015–2017) from the coast of New South Wales, Australia found 99.38% of samples were within regulatory limits. Diarrhetic shellfish toxins (DSTs) were present in 34.27% of 321 samples but only in pipis (P. deltoides), with two samples above the regulatory limit. Comparison of these market survey data to samples (phytoplankton in water and biotoxins in shellfish tissue) collected during the same period at wild harvest beaches demonstrated that, while elevated concentrations of Dinophysis were detected, a lag in detecting bloom events on two occasions meant that wild harvest shellfish with DSTs above the regulatory limit entered the marketplace. Concurrently, data (phytoplankton and biotoxin) from Sydney rock oyster (Saccostrea glomerata) harvest areas in estuaries adjacent to wild harvest beaches impacted by DSTs frequently showed elevated Dinophysis concentrations, but DSTs were not detected in oyster samples. These results highlighted a need for distinct management strategies for different shellfish species, particularly during Dinophysis bloom events. DSTs above the regulatory limit in pipis sampled from the marketplace suggested there is merit in looking at options to strengthen the current wild harvest biotoxin management strategies.


PLoS ONE ◽  
2015 ◽  
Vol 10 (7) ◽  
pp. e0132094 ◽  
Author(s):  
Yongjun Zhang ◽  
Qing S. Cao ◽  
Daniel I. Rubenstein ◽  
Sen Zang ◽  
Melissa Songer ◽  
...  

2002 ◽  
Vol 94 (1) ◽  
pp. 136 ◽  
Author(s):  
Sangamesh V. Angadi ◽  
Martin H. Entz

2010 ◽  
Vol 9 (3) ◽  
pp. 548-560 ◽  
Author(s):  
Ronald J. Ryel ◽  
A. Joshua Leffler ◽  
Carolyn Ivans ◽  
Michael S. Peek ◽  
Martyn M. Caldwell

1993 ◽  
Vol 33 (2) ◽  
pp. 245 ◽  
Author(s):  
PG Tow

The persistence and water use efficiency of Digitaria eriantha spp. eriantha and Hunter river lucerne were compared on red solodic soil with a hardsetting surface and poor internal drainage, on the North- West Slopes of New South Wales. After prolonged watering, the profile was wet to a depth of 48 � 1.5 cm, with an available moisture store of 90 mm. Over 3 years, persistence of digitaria was excellent. The population of lucerne was reduced following flooding at summer temperatures, Dry matter production of nitrogen (N) fertilised digitaria per mm warm season rainfall was similar to that of tropical grasses adapted to comparable rainfall environments in subtropical Queensland. Lucerne dry matter per mm rainfall was only about half that of digitaria (3.2 v. 6.3 kg). Lucerne grew well in mixture with digitaria except under prolonged wet soil conditions in summer. Artificial solodic profiles were constructed in the glasshouse to compare digitaria and lucerne in monoculture and mixture under varying temperature, moisture, and N regimes. Lucerne showed sensitivity to both high and low moisture levels at summer temperatures but performed very well at spring temperatures and moderate moisture levels where the mean evapotranspiration ratio was 400 g water per g dry matter. Water use efficiency was higher in digitaria than in lucerne, except at spring temperatures without added N. Water use efficiency of the mixture was always similar to that of the most efficient monoculture of the particular treatment.


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