Cost-benefit trade-offs of bird activity in apple orchards

Birds active in apple orchards in south–eastern Australia can contribute positively (e.g., control crop pests) or negatively (e.g., crop damage) to crop yields. Our study is the first to identify net outcomes of these activities, using six apple orchards, varying in management intensity, in south–eastern Australia as a study system. We also conducted a predation experiment using real and artificial codling moth (Cydia pomonella) larvae (a major pest in apple crops). We found that: (1) excluding birds from branches of apple trees resulted in an average of 12.8% more apples damaged by insects; (2) bird damage to apples was low (1.9% of apples); and (3) when trading off the potential benefits (biological control) with costs (bird damage to apples), birds provided an overall net benefit to orchard growers. We found that predation of real codling moth larvae was higher than for plasticine larvae, suggesting that plasticine prey models are not useful for inferring actual predation levels. Our study shows how complex ecological interactions between birds and invertebrates affect crop yield in apples, and provides practical strategies for improving the sustainability of orchard systems.

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Opportunities and trade-offs in dual-purpose cereals across the southern Australian mixed-farming zone: a modelling study

Animal Production Science ◽

10.1071/an09006 ◽

2009 ◽

Vol 49 (10) ◽

pp. 759 ◽

Cited By ~ 39

Author(s):

Andrew D. Moore

Keyword(s):

Western Australia ◽

Production Systems ◽

Wheat Yield ◽

Livestock Production ◽

Relative Reduction ◽

Dual Purpose ◽

South Eastern ◽

Trade Offs ◽

Eastern Australia ◽

South Eastern Australia

Dual-purpose cereals are employed in the high-rainfall zone of southern Australia to provide additional winter forage. Recently there has been interest in applying this technology in the drier environments of South and Western Australia. It would therefore be useful to gain an understanding of the trade-offs and risks associated with grazing wheat crops in different locations. In this study the APSIM (Agricultural Production Systems Simulator) crop and soil simulation models were linked to the GRAZPLAN pasture and livestock models and used to examine the benefits and costs of grazing cereal crops at 21 locations spanning seven of the regions participating in the Grain & Graze research, development and extension program. A self-contained part of a mixed farm (an annual pasture–wheat rotation plus permanent pastures) supporting a breeding ewe enterprise was simulated. At each location the consequences were examined of: (i) replacing a spring wheat cultivar with a dual-purpose cultivar (cv. Wedgetail or Tennant) in 1 year of the rotation; and (ii) either grazing that crop in winter, or leaving it ungrazed. The frequency of early sowing opportunities enabling the use of a dual-purpose cultivar was high. When left ungrazed the dual-purpose cultivars yielded less grain on average (by 0.1–0.9 t/ha) than spring cultivars in Western Australia and the Eyre Peninsula but more (by 0.25–0.8 t/ha) in south-eastern Australia. Stocking rate and hence animal production per ha could be increased proportionately more when a dual-purpose cultivar was used for grazing; because of the adjustments to stocking rates, grazing of the wheat had little effect on lamb sale weights. Across locations, the relative reduction in wheat yield caused by grazing the wheats was proportional to the grazing pressure upon them. Any economic advantage of moving to a dual-purpose system is likely to arise mainly from the benefit to livestock production in Western Australia, but primarily from grain production in south-eastern Australia (including the Mallee region). Between years, the relationship between increased livestock production and decreased grain yield from grazing crops shifts widely; it may therefore be possible to identify flexible grazing rules that optimise this trade-off.

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Wintering and spring emergence of codling moth, Cydia pomonella (L) (Lepidoptera: Tortricidae) in south eastern Australia.

Australian Journal of Zoology ◽

10.1071/zo9630431 ◽

1963 ◽

Vol 11 (4) ◽

pp. 431 ◽

Cited By ~ 6

Author(s):

PW Geier

Keyword(s):

Predictive Models ◽

Adaptive Response ◽

Cydia Pomonella ◽

Codling Moth ◽

South Eastern ◽

Climatic Variations ◽

Temperature Regimes ◽

Eastern Australia ◽

Spring Emergence ◽

South Eastern Australia

Codling moth winters as dormant fifth instar larvae which complete their development in spring. In south-eastern Australia, three temperature regimes contribute to determine the emergence times of spring adults, i.e. a conditioning regime in autumn, a chilling regime in winter, and a dormancy-ending regime in spring. The influences of each regime are examined and discussed. Short winters and early springs tend to increase the variability of emergence dates. This is thought to represent an important adaptive response of the species to climatic variations. Comprehensive predictive models of spring brood events cannot be made at present for lack of sufficient knowledge of the various processes involved.

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Persistence and leaching of sulfonylurea herbicides over a 4-year period in the highly alkaline soils of south-eastern Australia

Australian Journal of Experimental Agriculture ◽

10.1071/ea04221 ◽

2006 ◽

Vol 46 (8) ◽

pp. 1069 ◽

Cited By ~ 21

Author(s):

K. L. Hollaway ◽

R. S. Kookana ◽

D. M. Noy ◽

J. G. Smith ◽

N. Wilhelm

Keyword(s):

Crop Damage ◽

Sulfonylurea Herbicides ◽

Alkaline Soils ◽

Metsulfuron Methyl ◽

South Eastern ◽

Eastern Australia ◽

Current Product ◽

Potential Damage ◽

Ph Range ◽

South Eastern Australia

The sulfonylurea herbicides are commonly used in the cereal belt of south-eastern Australia and there is concern that their persistence in alkaline soils is long enough to damage subsequent rotational crops such as legumes and oilseeds. In this study, we investigated leaching and persistence of 3 commonly used herbicides (chlorsulfuron, triasulfuron and metsulfuron-methyl) in alkaline soils of south-eastern Australia (pH range 7.4–8.6) for at least 4 years after treatment. In general, chlorsulfuron was predicted to persist for 3–5 years [time to degrade to 1% (DT99) of 33–63 months after treatment depending on the field site], triasulfuron for 1–3 years (DT99 of 13–37 months after treatment), and metsulfuron-methyl for less than 1 year (although data were insufficient for degradation estimates) after its application. However, this varied between sites and years of application. Although, the majority of residues remained in the top 20 cm of the soil profile throughout the study, leaching of a small fraction of the residue to deeper layers of the profiles (up to 1 m) was observed. Despite their slow rate of degradation, the herbicides did eventually dissipate, even in soils with very high pH (8.5). In most cases, the current product labels provide an adequate safety period to protect sensitive rotational crops from potential damage due to excessive persistence. However, in particular years at 3 of the 5 field sites, metsulfuron-methyl and triasulfuron persisted beyond the recommended recropping period (9 months for metsulfuron-methyl and 22 months for triasulfuron in soils up to pH 7.5 or 24 months in soils pH 7.6 and above). An accurate measurement of soil pH and its variability within the paddock is essential to minimise any subsequent crop damage by these herbicides.

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Carbon-neutral wool farming in south-eastern Australia

Animal Production Science ◽

10.1071/an15541 ◽

2016 ◽

Vol 56 (3) ◽

pp. 417 ◽

Cited By ~ 9

Author(s):

Natalie A. Doran-Browne ◽

John Ive ◽

Phillip Graham ◽

Richard J. Eckard

Keyword(s):

Soil Carbon ◽

Greenhouse Gas ◽

Carbon Stocks ◽

Pasture Production ◽

South Eastern ◽

Trade Offs ◽

Eastern Australia ◽

Soil Carbon Stocks ◽

Carbon Neutral ◽

South Eastern Australia

Ruminant livestock production generates higher levels of greenhouse gas emissions (GHGE) compared with other types of farming. Therefore, it is desirable to reduce or offset those emissions where possible. Although mitigation options exist that reduce ruminant GHGE through the use of feed management, flock structure or breeding management, these options only reduce the existing emissions by up to 30% whereas planting trees and subsequent carbon sequestration in trees and soil has the potential for livestock emissions to be offset in their entirety. Trees can introduce additional co-benefits that may increase production such as reduced salinity and therefore increased pasture production, shelter for animals or reduced erosion. Trees will also use more water and compete with pastures for water and light. Therefore, careful planning is required to locate trees where the co-benefits can be maximised instead of any negative trade-offs. This study analysed the carbon balance of a wool case study farm, Talaheni, in south-eastern Australia to determine if the farm was carbon neutral. The Australian National Greenhouse Gas Inventory was used to calculate GHGE and carbon stocks, with national emissions factors used where available, and otherwise figures from the IPCC methodology being used. Sources of GHGE were from livestock, energy and fuel, and carbon stocks were present in the trees and soil. The results showed that from when the farm was purchased in 1980–2012 the farm had sequestered 11 times more carbon dioxide equivalents (CO2e) in trees and soil than was produced by livestock and energy. Between 1980 and 2012 a total of 31 100 t CO2e were sequestered with 19 300 and 11 800 t CO2e in trees and soil, respectively, whereas farm emissions totalled 2800 t CO2e. There was a sufficient increase in soil carbon stocks alone to offset all GHGE at the study site. This study demonstrated that there are substantial gains to be made in soil carbon stocks where initial soils are eroded and degraded and there is the opportunity to increase soil carbon either through planting trees or introducing perennial pastures to store more carbon under pastures. Further research would be beneficial on the carbon-neutral potential of farms in more fertile, high-rainfall areas. These areas typically have higher stocking rates than the present study and would require higher levels of carbon stocks for the farm to be carbon neutral.

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