The effect of engineered features on sources and sinks of nutrients on a dairy farm in south-eastern Australia

Dairy production systems in south-eastern Australia are based primarily on grazed pasture. Perennial ryegrass (Lolium perenne L.) is the major grass species used in this region and farmers are faced with the challenge of choosing from more than 60 commercially available cultivars. This paper describes the development of a system termed as a forage value index that ranks the overall performance of perennial ryegrass cultivars relative to cultivar Victorian according to the summation of the estimated difference in the value of seasonal dry-matter (DM) yield of the cultivars. Average predicted seasonal DM yields were calculated by analysing the results of eight available perennial ryegrass plot trials across south-eastern Australia, using a multi-environment, multi-harvest linear mixed model. The differences in the model-predicted DM yield of each cultivar was compared with cultivar Victorian in each of five seasonal periods (autumn, winter, early spring, late spring, summer) to generate a series of performance values (1 per period) for each cultivar. Each performance value was then multiplied by an economic value (AU$/kg extra pasture grown) relating to each of four regions (Gippsland, northern Victoria, south-western Victoria, Tasmania) and seasonal period and aggregated to generate an overall forage value index rating for each cultivar. Economic values ranged from AU$0.11 to AU$0.39 per extra kilogram of DM grown, depending on the season and region, which translated into estimated benefits on dairy farms of up to AU$183 per ha per year for farmers that use high-yielding cultivars in place of cultivar Victorian perennial ryegrass.

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Variation in the Nutritive Characteristics of Modern Perennial Ryegrass Cultivars in South-Eastern Australian Dairy Environments and Prospects for Inclusion in the Australian Forage Value Index (FVI)

Agronomy ◽

10.3390/agronomy12010136 ◽

2022 ◽

Vol 12 (1) ◽

pp. 136

Author(s):

Clare Leddin ◽

Khageswor Giri ◽

Kevin Smith

Keyword(s):

Functional Groups ◽

Perennial Ryegrass ◽

Nutritive Value ◽

Dairy Farm ◽

Breeding Programs ◽

South Eastern ◽

Individual Trait ◽

Eastern Australia ◽

Forage Value ◽

South Eastern Australia

Perennial ryegrass (PRG) is an important forage grown on dairy farms in temperate regions globally, including south-eastern Australia. A forage value index (FVI) providing information on the seasonal production of commercially available PRG cultivars is currently available. Despite the importance of the nutritive value of pasture in dairy farm systems, the nutritive characteristics of PRG cultivars are not currently included in the FVI as they are not routinely measured in cultivar evaluation trials. This study investigated differences between cultivar functional groups (diploid and tetraploid). It also examined differences between individual cultivars within seasons at four locations in south-eastern Australia and examined how trial location affects cultivar ranking. Samples were collected from existing cultivar evaluation trials over a 3-year period and analysed for nutritive characteristics. There were differences (p < 0.05) between diploids and tetraploids for metabolisable energy (ME) and neutral detergent fibre (NDF) in each season at each location with a few exceptions in summer and autumn. Crude protein (CP) differed between functional groups in some seasons at some sites. Spearman rank correlations within season were strong for ME between trial locations (r = 0.78–0.96), moderate to high for NDF (0.51–0.86) and variable for CP (−0.69–0.56). These findings provide guidance on methods for implementing nutritive value testing in cultivar evaluation trials and support the imminent inclusion of ME in the Australian FVI. The ranking of cultivars for ME was more consistent across trial sites compared to NDF and CP, suggesting the latter two traits, in particular CP, are more sensitive to environmental influences. Based on these results, we do not recommend the inclusion of CP as an individual trait in the Australian FVI. A significantly larger dataset and further research on the genotype by environment interactions would be needed to reconsider this. The addition of ME in the Australian FVI will lead to better cultivar choices by farmers and could lead to more targeted perennial ryegrass breeding programs.

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Soil compaction controls the abundance, biomass and distribution of earthworms in a single dairy farm in south-eastern Australia

Soil and Tillage Research ◽

10.1016/j.still.2006.07.006 ◽

2007 ◽

Vol 94 (1) ◽

pp. 75-82 ◽

Cited By ~ 40

Author(s):

K.Y. Chan ◽

I. Barchia

Keyword(s):

Soil Compaction ◽

Dairy Farm ◽

South Eastern ◽

Eastern Australia ◽

South Eastern Australia

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Phosphorus export at the paddock, farm-section, and whole farm scale on an irrigated dairy farm in south-eastern Australia

Australian Journal of Agricultural Research ◽

10.1071/ar04166 ◽

2005 ◽

Vol 56 (1) ◽

pp. 1 ◽

Cited By ~ 32

Author(s):

K. Barlow ◽

D. Nash ◽

R. B. Grayson

Keyword(s):

Surface Runoff ◽

Water Reuse ◽

Agricultural Land ◽

Dairy Farm ◽

South Eastern ◽

Eastern Australia ◽

Farm Scale ◽

Phosphorus Export ◽

South Eastern Australia

Phosphorus (P) exported from agricultural land contributes to the eutrophication of inland water systems. Although P export has been extensively researched at the paddock scale, our understanding of farm-scale export is limited. This paper presents the results of a 3-year monitoring project that investigated P export at the paddock, farm-section, and whole farm scales on an irrigated dairy farm in south-eastern Australia. Annual average concentrations of 2.2–11 mg P/L, and annual loads of 2.5–23 kg P/ha were measured at the paddock and farm-section scale over the 3 years, with the quality of irrigation water applied having no significant effect on P export in surface runoff. At the farm scale, effective management of the water reuse system significantly reduced phosphorus export by up to 98%. During the 3-year period, P concentrations and loads exported in surface runoff consistently decreased between the paddock and farm-section scales (e.g. P-28 exported 13.8 kg P/ha, whereas S-4 exported 6.7 kg/ha in 2001), with the decrease in P export described using a scaling factor. Our results suggest that data on paddock-scale P export can rarely be proportionally assigned to predict section- or farm-scale export, at least on irrigated dairy farms in south-eastern Australia.

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