scholarly journals The Potential of Deep Roots to Mitigate Impacts of Heatwaves and Declining Rainfall on Pastures in Southeast Australia

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1641
Author(s):  
Rachelle Meyer ◽  
Alexandria Sinnett ◽  
Ruchika Perera ◽  
Brendan Cullen ◽  
Bill Malcolm ◽  
...  
Keyword(s):  
Growing Season ◽  
Economic Modelling ◽  
Climate Scenarios ◽  
Deep Roots ◽  
Summer Dormancy ◽  
Grazing Systems ◽  
Metabolisable Energy ◽  
Sustainable Grazing ◽  
Adaptation Options ◽  
Short Growing Season

Declines in growing-season rainfall and increases in the frequency of heatwaves in southern Australia necessitate effective adaptation. The Sustainable Grazing Systems Pasture Model (SGS) was used to model the growth of three pasture species differing in root depth and root distribution under three different climate scenarios at two sites. The modelled metabolisable energy intake (in MJ) was used in a partial discounted net cash flow budget. Both the biophysical and economic modelling suggest that deep roots were advantageous in all climate scenarios at the long growing season site but provided no to little advantage at the short growing season site, likely due to the deep-rooted species drying out the soil profile earlier. In scenarios including climate change, the DM production of the deep-rooted species at the long growing season site averaged 386 kg/ha/year more than the more shallow-rooted species, while at the site with a shorter growing season it averaged 205 kg/ha/year less than the shallower-rooted species. The timing of the extra growth and pasture persistence strongly influenced the extent of the benefit. At the short growing season site other adaptation options such as summer dormancy will likely be necessary.

The Sustainable Grazing Systems Pasture Model: description, philosophy and application to the SGS National Experiment

2003 ◽  
Vol 43 (8) ◽  
pp. 711 ◽  
Author(s):  
I. R. Johnson ◽  
G. M. Lodge ◽  
R. E. White
Keyword(s):  
Nutrient Dynamics ◽  
Physiological Model ◽  
Climatic Conditions ◽  
Model Description ◽  
Continuous Grazing ◽  
Grazing Systems ◽  
Animal Growth ◽  
Metabolisable Energy ◽  
Sustainable Grazing ◽  
Water Nutrients

A biophysical simulation model (the Sustainable Grazing Systems Pasture Model) was developed as an integral part of the Sustainable Grazing Systems National Experiment. It was developed to meet the needs of the researchers both for analysing data and processes at individual sites, and for simulating the outcome of these processes operating in generic pasture systems on a range of soil types, under specific grazing managements. The model was designed to reside on the desktops of individual researchers and for those researchers to be part of its development process.The Sustainable Grazing Systems Pasture Model incorporates the following: a physiological model of pasture species herbage accumulation in response to climatic conditions; the water balance including evapotranspiration, runoff (surface and subsurface), infiltration and drainage; pasture utilisation by grazing animals; a metabolisable energy-based animal growth model; and organic matter and inorganic nutrient dynamics (for nitrogen, phosphorus, potassium and sulfur) including plant uptake, adsorption, leaching, nitrogen fixation by legumes, and atmospheric nitrogen losses. A range of grazing options (set-stocking, rotational grazing and continuous grazing at a variable rate) is available for ewes and lambs, and wethers. Each of the main modules (water, nutrients, pastures and animals) is interconnected. To avoid bias in the influence of any one module, each is described at about the same level of complexity, with the description of any process being restricted to about 5 parameters. The model is hierarchical in structure and most processes are described in terms of a series of fluxes (or, more specifically, flux densities) that have dimensions of amount per area per time.The model can be closely linked to a database specifically developed for the Sustainable Grazing Systems National Experiment to allow easy importing and exporting of climate and experimental data for comparison with model output. This paper gives an overview of the model structure and its output, the process that was used for its development within Sustainable Grazing Systems, and its use by the Sustainable Grazing Systems sites and themes. Comments are provided on the implementation of the development process to assist future programs using a similar approach.

scholarly journals Interannual Variation in Root Production in Grasslands Affected by Artificially Modified Amount of Rainfall

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Karel Fiala ◽  
Ivan Tůma ◽  
Petr Holub
Keyword(s):  
Interannual Variation ◽  
Plant Biomass ◽  
Growing Season ◽  
Lower Amount ◽  
Root Production ◽  
Climate Scenarios ◽  
Natural Rainfall ◽  
Plant Matter ◽  
Grassland Ecosystems ◽  
Below Ground

The effect of different amounts of rainfall on the below-ground plant biomass was studied in three grassland ecosystems. Responses of the lowland (dryFestucagrassland), highland (wetCirsiumgrassland), and mountain (Nardusgrassland) grasslands were studied during five years (2006–2010). A field experiment based on rainout shelters and gravity irrigation simulated three climate scenarios: rainfall reduced by 50% (dry), rainfall increased by 50% (wet), and the natural rainfall of the current growing season (ambient). The interannual variation in root increment and total below-ground biomass reflected the experimentally manipulated amount of precipitation and also the amount of current rainfall of individual years. The effect of year on these below-ground parameters was found significant in all studied grasslands. In comparison with dryFestucagrassland, better adapted to drought, submontane wetCirsiumgrassland was more sensitive to the different water inputs forming rather lower amount of below-ground plant matter at reduced precipitation.

Dietary preferences of domestic ruminants

1997 ◽  
Vol 20 ◽  
pp. 96-97 ◽  
Author(s):  
S. M. Rutter ◽  
P. D. Penning ◽  
A. J. Parsons ◽  
A. Harvey ◽  
R. J. Orr
Keyword(s):  
Plant Species ◽  
Perennial Ryegrass ◽  
Animal Species ◽  
Sheep Grazing ◽  
Dietary Preference ◽  
Dietary Preferences ◽  
Complex Interactions ◽  
Domestic Ruminants ◽  
Grazing Systems ◽  
Sustainable Grazing

To develop sustainable grazing systems, an understanding of the complex interactions between competing plant species and grazing herbivores is needed. An understanding of dietary preference is a prerequisite to predicting how much and from which plant species animals select. This work initially concentrated on dietary preferences of sheep grazing perennial ryegrass and white clover swards and was then extended to other animal species to test the generality of our findings.

Fermentation kinetic, chemical composition, organic matter degradation and metabolisable energy of three non-cultivated pastures located in the central plateau of Mexico

2009 ◽  
Vol 2009 ◽  
pp. 92-92
Author(s):  
A A Rayas-Amor ◽  
P Dorward ◽  
T Rehman ◽  
F L Mould ◽  
O A Castelan-Ortega
Keyword(s):  
Economic Benefit ◽  
Nutritive Value ◽  
Growing Season ◽  
Production Costs ◽  
Grass Species ◽  
Organic Matter Degradation ◽  
Central Plateau ◽  
Maize Stover ◽  
Resource Poor ◽  
Metabolisable Energy

Approximately 80% of all production costs are related to the purchase of forages and other feeds in dairy enterprises in Mexico. Resource poor, smallholder (campesino) systems are heavily reliant on the use of maize stover, noncultivated/cultivated grass species and weeds to feed their dairy cattle, thus a nutritional understanding of local forage resources would be of considerable economic benefit. The objective of this study was to determine the nutritive value of non-cultivated pastures (NcP) across the growing season.

Phenology and Tiller Characteristics of Big Bluestem and Switchgrass Cultivars in a Short Growing Season Area

1998 ◽  
Vol 90 (4) ◽  
pp. 489-495 ◽  
Author(s):  
Ignacio Madakadze ◽  
Bruce E. Coulman ◽  
K. Stewart ◽  
P. Peterson ◽  
R. Samson ◽  
...  
Keyword(s):  
Growing Season ◽  
Big Bluestem ◽  
Short Growing Season

Carbon resource sharing and rhizome expansion of Phalaris aquatica plants in grazed pastures

2005 ◽  
Vol 32 (1) ◽  
pp. 79 ◽  
Author(s):  
Brendan R. Cullen ◽  
David F. Chapman ◽  
Paul E. Quigley
Keyword(s):  
Resource Sharing ◽  
Seasonal Pattern ◽  
Soil Surface ◽  
Deep Roots ◽  
Phalaris Aquatica ◽  
Plant Parts ◽  
Grazed Pastures ◽  
Below Ground ◽  
Grazing Systems ◽  
Western Victoria

The patterns of carbon (C) resource sharing and new rhizome development in phalaris (Phalaris aquatica L. cv. Australian) were examined in grazed pastures in western Victoria. The seasonal pattern of new rhizome growth was similar under the four grazing systems tested. New rhizome production was infrequent but concentrated in winter. The phalaris plants maintained more than 1600 kg DW ha–1 of non-assimilating material beneath the soil surface (0–5 cm). Gaseous 14C was fed into plants in the field to determine if these below ground structures continued to be supported by the C assimilating tillers. The results indicated that the primary tiller does provide C to support the growth of secondary and tertiary tillers derived from its axillary buds. There was some evidence that C was exported from the fed tiller to non-assimilating plant structures. The old reproductive tiller bases (from which the assimilating tillers originate) received some C support, suggesting that this was maintained because it had deep roots attached. C export to older plant parts declined, which may lead to plant fragmentation.

Quackgrass (Agropyron repens) Control with Fall-Applied Glyphosate and Other Herbicides

Weed Science ◽  
1981 ◽  
Vol 29 (4) ◽  
pp. 382-386 ◽  
Author(s):  
J. A. Ivany
Keyword(s):  
Good Control ◽  
Growing Season ◽  
Atlantic Canada ◽  
Poor Control ◽  
Excellent Control ◽  
Pre Treatment ◽  
Short Growing Season ◽  
Agropyron Repens

The herbicides glyphosate [N-(phosphonomethyl)glycine], hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione], and pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynl)benzamide] were evaluated for effectiveness in quackgrass (Agropyron repensL. Beauv.) control when applied in the fall, a time that is desirable in a short-growing-season area such as Atlantic Canada. Glyphosate at 1.12 kg/ha applied to quackgrass in grain stubble gave good control. Glyphosate at 1.12 kg/ha in late October gave better control than the same rate applied in late September. At low rates of 0.56 and 1.12 kg/ha, glyphosate gave better quackgrass control when fall-applied than when spring-applied. No differences were noted between seasons at the 2.24-kg/ha rate of glyphosate. Pre-treatment with nitrogen at 35 kg/ha 30 or 15 days before application, or on the day of application, did not improve quackgrass control with glyphosate. Pronamide gave fair to good control. Hexazinone at 2.24, 4.48, or 6.72 kg/ha gave poor control when fall-applied, but excellent control when spring-applied.

Evaluation of the impact of SGS on livestock producers and their practices

2003 ◽  
Vol 43 (8) ◽  
pp. 1031 ◽  
Author(s):  
C. J. Allan ◽  
W. K. Mason ◽  
I. J. Reeve ◽  
S. Hooper
Keyword(s):  
Management Practices ◽  
Red Meat ◽  
Annual Rainfall ◽  
Pasture Management ◽  
High Rainfall ◽  
Grazing Systems ◽  
Sustainable Grazing ◽  
The Impact ◽  
Improved Pasture

The Sustainable Grazing Systems (SGS) Program has assisted producers in the high rainfall zone (HRZ, annual rainfall >600 mm/year) of southern Australia, by developing and delivering more productive and sustainable grazing systems. It was evaluated by 2 external surveys — a benchmarking survey in 1994 before the start of SGS, and a follow-up survey of producers in 2001. The 2001 survey showed that SGS had assisted red meat and wool producers in southern Australia make significant and beneficial changes to their grazing systems. Substantial changes in grazing practices occurred between 1994 and 2001 in the HRZ. These changes included an increase in the number of producers who rotationally graze (25%), as well as those undertaking practices aimed at improved pasture management. Participants in SGS were more likely to have made changes to their grazing systems than non-participants. There were no overt differences between regions in producer demographics, or changes made to management practices. The survey confirmed SGS had achieved its goal. Sixty percent of producers in the target regions were aware of SGS (out of a total of 23 689 producers); 42% (9839) had some involvement with SGS and/or received the SGS magazine 'Prograzier'; while 26% (6141) actively participated in SGS through undertaking a PROGRAZE course, and/or by attending regional SGS activities. Of the estimated 9839 producers who participated in the program, up to 8000 made beneficial changes to enhance the productivity and sustainability of their grazing operations. Active participants (6141) attributed many of these benefits to their involvement in SGS.

Sustainable grazing systems for the Central Tablelands of New South Wales. 5. A bioeconomic framework for assessing the long-term economic benefits of grazing management tactics and implications for sustainability

2006 ◽  
Vol 46 (4) ◽  
pp. 495 ◽  
Author(s):  
R. E. Jones ◽  
P. M. Dowling ◽  
D. L. Michalk ◽  
W. McG. King
Keyword(s):  
Programming Model ◽  
New South ◽  
New South Wales ◽  
Economic Benefits ◽  
Grazing Management ◽  
South Wales ◽  
Grazing Systems ◽  
Sustainable Grazing ◽  
Management Tactics

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.

The Sustainable Grazing Systems National Experiment. 2. Scientific outcomes and effectiveness of the research and development processes

2003 ◽  
Vol 43 (8) ◽  
pp. 993 ◽  
Author(s):  
M. H. Andrew ◽  
G. M. Lodge ◽  
W. K. Mason ◽  
R. J. Price
Keyword(s):  
Research And Development ◽  
Perennial Grasses ◽  
Experiment Research ◽  
Data Set ◽  
Innovative Research ◽  
Individual Site ◽  
Research Findings ◽  
Development Processes ◽  
Grazing Systems ◽  
Sustainable Grazing

The Sustainable Grazing Systems (SGS) National Experiment used 13 innovative research and development integrating processes to combine 6 diverse research sites across the southern high rainfall zone into a single, integrated experiment. Sites collected a common data set about the productivity and sustainability of grazing systems, so that issues beyond the site level could be explored. Essential to this approach were database and modelling tools that enabled across-site issues to be examined by a mix of conventional data analyses and modelling scenarios. This had not been previously attempted at this scale for the Australian grazing industries. Major outcomes from the individual site and theme analyses were tabulated, providing a comprehensive summary of the SGS National Experiment research findings. Many of the research findings were new, and overall the SGS National Experiment improved our understanding of the processes operating in grazing systems and their interactions. The main conclusion from this substantive study was that graziers can use a combination of strategies to enhance the productivity and sustainability of their pastures, such as sowing deep-rooted perennial grasses, enhanced soil fertility, amelioration of low soil pH, and grazing methods that include rotation and rest. Since the SGS National Experiment was itself an experiment, participants were surveyed to assess the integrating processes used, their implementation, and leadership and influence within the SGS National Experiment research group. Researchers rated the 13 innovative research and development processes for their potential to improve research and for the extent to which the processes were effectively implemented within SGS. The average potential score was 8.2 (out of 10). Four integrating processes had a potential score ≥9.0: the investment in a communication and product development year (the 'harvest year'); a common database structure across all sites; the use of themes to integrate across sites; and the use of protocols and minimum datasets to guide the research and data collection. We discuss possible ways to make these processes more effective. While 18 researchers had defined and active leadership roles from the outset of the SGS National Experiment, 2 researchers dominated the scientific influence and leadership.Despite some implementation problems with the SGS National Experiment processes, internal and external reviews indicated that the SGS National Experiment met most of its goals and objectives. Because of the processes implemented, the SGS National Experiment framework has provided a new benchmark for conducting large-scale rural research in Australia.

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