ORCID Profile
0000-0002-4159-4525
Current Organisation
AgResearch Ltd
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Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CP13263
Abstract: Ecological studies often suggest that natural grasslands with high species ersity will grow more biomass and leach less nitrogen (N). If this ersity effect also applies to fertilised and irrigated pastures with controlled removal of herbage, it might be exploited to design pastures that can assist the dairy industry to maintain production while reducing N leaching losses. The purpose of this study was to test whether pasture mixtures with a high functional ersity in ryegrass traits will confer on the system higher water- and N-use efficiency. The hypothesis was tested using a process-based model in which pasture mixtures were created with varying levels of ersity in ryegrass traits likely to affect pasture growth. Those traits were: the winter- or summer-dominance of growth, the ability of the plant to intercept radiation at low pasture mass, and rooting depth. Pasture production, leaching and water- and N-use efficiency were simulated for management typical of a dairy pasture. We found that the performance of the erse ryegrass–clover mixtures was more strongly associated with the performance of the in idual components than with the ersity across the components. Diverse pasture mixtures may confer other benefits, e.g. pest or disease resistance and pasture persistence. The testing here was within a selection of ryegrasses, and the greater possible ersity across species may produce different effects. However, these results suggest that highly performing pastures under fertilised and irrigated grazed conditions are best constructed by selecting components that perform well in idually than by deliberately introducing ersity between components.
Publisher: Elsevier BV
Date: 06-2011
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP08352
Abstract: There is an impetus to re-vegetate components of the Western Australian wheatbelt to address salinity and improve ecosystem function. In this study we use precision agriculture (PA) technologies and other methods to identify poor-performing patches for three farms, using historical yield maps to assess the ecological value associated with their potential re-vegetation. We also investigate how these patches changed with varying definitions of poor performance. Overall, poor-performing patches were rare and occupied 11.3, 13.5, and 25.3% of farmland across three farms, using the most aggressive definition of poor performance, which included the greatest proportion of arable land. We subsequently assessed the effect that re-vegetating these patches had on a suite of landscape metrics quantifying ecological value. On two farms, mean patch sizes were less than 1.2 ha for all definitions of poor performance. On the third farm, mean patch size increased from 0.9 ha to 2.6 ha as the definition of poor crop performance was altered to include more arable land. Patches were generally small and dispersed, did not significantly enhance connectivity in the landscape, and were therefore of limited ecological value. In general, re-vegetating poor-performing patches alone will provide little ecological benefit when re-vegetation is restricted to unproductive land. The ecological value of re-vegetation strategies in this landscape will improve only if some additional productive agricultural land is also taken out of production and re-vegetated.
No related grants have been discovered for Michael Dodd.