Crop stubbles are as important for sheep production as annual pastures in the Victorian Mallee

Robertson, Susan

doi:10.1071/ea04033

Cited by 8 publications

(7 citation statements)

References 15 publications

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“…However, given its wide geographic distribution and apparent ability to persist in Mallee cropping systems, spiny M. minima has some value as a pasture species if compared with sub-optimally managed commercial medics. The plant density of commercial medics is usually much lower on farms in the Mallee (<200 plants/m 2 ) (Rigby and Latta 1995) than for the field trials reported here, whereas the density of naturalised stands of spiny M. minima can be higher than that recorded in Experiment 5 (Robertson 2005). The relative densities may be such that M. minima pastures could be as productive as commercial medics under some farm conditions.…”

Section: Productivity Of Species In Fieldcontrasting

confidence: 46%

Do some naturalised legumes have the potential to improve pasture production in the Victorian Mallee?

Robertson¹,

Smith²

2006

Aust. J. Exp. Agric.

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Some naturalised (not commercialised or deliberately sown) annual pasture legumes may be valuable pasture components, but their production relative to commercial species is poorly defined. This study aimed to determine the relative productivity, morphology, nutritive value, ecotype variation and sulfonylurea tolerance of some naturalised species in the Victorian Mallee. A series of 3 glasshouse and 2 ungrazed field experiments compared the production of haresfoot clover (Trifolium arvense L.), little woolly burr medic (Medicago minima L.), spineless M. minima, and M. monspeliaca (L.) Trautv. with the commercial species strand medic (M. littoralis Loisel cv. Herald) and barrel medic (M. truncatula Gaertn cv. Paraggio). The crude protein and in vitro digestibility of leaf and stem components were similar among species. The proportion of leaf was associated with species maturity, with later maturing species having a greater proportion of leaf at each harvest. There was a range of 52 days among species for date of first flowering. T. arvense produced similar or more biomass than the commercial species in spring, but had lower winter production. A 38-day range in days to first flower and a 2-fold range in winter biomass production among T. arvense ecotypes indicate potential for selection within this species. T. arvense also appears to have greater tolerance of triasulfuron residues than M. littoralis. Spineless M. minima requires further evaluation for persistence in this environment, but the low production of M. monspeliaca limits its value as a component of pastures. T. arvense, spineless and spiny M. minima all have some characteristics which could enhance pasture production in low-rainfall, low-input mixed farming systems.

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Section: Productivity Of Species In Fieldcontrasting

confidence: 46%

Do some naturalised legumes have the potential to improve pasture production in the Victorian Mallee?

Robertson¹,

Smith²

2006

Aust. J. Exp. Agric.

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“…It is the residue left after harvesting using a shearing handpiece . This calibration is based on data from dense improved pastures and contrasts with the residual biomass of 45 3 kg DM/ha after harvest using blade shears in this environment (Robertson 2004). The tests with GrazFeed reported here demonstrate that sheep in this region must be accessing live herbage biomass well below 400 kg DM/ha to achieve the weight gains observed.…”

Section: Discussionmentioning

confidence: 92%

“…Observed herbage biomass from all data sources was assumed to equal total herbage biomass, rather than available herbage, because residual biomass was only reported for 1 data set in this environment (Robertson 2004) which showed that the quantities of residual biomass were not significant.…”

Section: Simulationsmentioning

confidence: 99%

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Predicting pasture and sheep production in the Victorian Mallee with the decision support tool, GrassGro

Robertson¹

2006

Aust. J. Exp. Agric.

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The GrassGro decision support tool was designed to quantify sheep and pasture production in response to management and climate variability in temperate Australia, and has been tested in temperate but not low-rainfall Australian conditions. Data from field experiments and from on-farm monitoring was used to test GrassGro predictions of annual and perennial pasture production, and sheep production at 4 locations throughout the Victorian Mallee, which is a low-rainfall area (275–375 mm annually). Predictions of long-term pasture production were then made. Predictions of the herbage biomass of annual pastures closely matched observed data for both a sandy loam (1991–2002 data) and a whole paddock (combining sandy loam and loam and sand) (2001–2002 data) soil type, at several locations across the Victorian Mallee. Linear regression between observed and simulated (April to September) data produced coefficients, significance and root mean square error of r2 = 0.81, P<0.001, 217 kg DM/ha, respectively, for sandy loam soil types and r2 = 0.94, P<0.001, 72 kg DM/ha, respectively, for whole paddock soil types. A series of simulations for individual years from 1970 to 2002 quantified the large impact of climate variability and demonstrated that seedbank and location, but not soil fertility, had a large influence on annual pasture production. However, GrassGro underestimated the production of the perennial pasture, lucerne (r2 = 0.2). GrassGro was also unable to adequately predict sheep production because it failed to take into account the sparse, clumpy structure of the low biomass pastures typical of this region. Methods to improve GrassGro were identified and included: (i) the need to adjust sheep intake from low biomass, sparse pastures, (ii) the ability to predict summer growing and autumn growing plant species, (iii) the ability to graze crop stubbles and (iv) refinements to the coefficients of equations used to model lucerne growth.

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“…In the dryland farming systems where wheat and barley are combined with sheep production, regular feed gaps over summer and autumn (Moore et al 2009) are commonly met by feed supplementation. The reliance on supplementary feeding limits farm profitability (Robertson 2006a) and explains low stocking rates and, therefore, low pasture utilisation and resource-use efficiency. With the revitalisation of the grazing component of mixed farming systems due to increasing wool and lamb prices (Bell and Moore 2012), strategies to close the feed gap by differentiating the feed-base are receiving renewed attention (Nichols et al 2007;Dear and Ewing 2008).…”

Section: Introductionmentioning

confidence: 99%

Summer-growing perennial grasses are a potential new feed source in the low rainfall environment of southern Australia

et al. 2014

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In the Mallee region of southern Australia, the dry and variable climate results in frequent summer–autumn feed gaps, restricting the profitability of farms that combine livestock and crop enterprises. To assess the suitability of summer-growing perennial grasses to fill such feed gaps, two replicated field experiments comparing the persistence and productivity of several cultivars were conducted at Hopetoun and Karoonda. The data from these experiments also served to validate a C4 grass model, which was then used in a simulation experiment comparing productivity on two different soil types at three locations. Most grass cultivars established well except on sandy, non-wetting soils. At Hopetoun, four of five cultivars persisted over 6 years, demonstrating the tolerance of the selected cultivars to the typical long, dry summers and cold, wet winters of the region. Biomass production showed little difference between cultivars and a strong response to the amount of summer rainfall, ranging from 1500 to 3000 kg ha–1 under average seasonal conditions and peaking at 9000 kg ha–1 in the very wet summer of 2010–2011. Model performance was satisfactory (R2 0.85–0.93, RMSE 476–1673 kg ha–1, depending on the cultivar), in terms of predicting both the magnitude and the timing of biomass production. Simulation outputs indicated that biomass production closely followed seasonal trends in temperature and moisture availability. Grazing potential was highest from early summer to autumn, which coincides with the period of feed shortages and highest marginal value of forage. In areas with warm-season (October–April) rainfall averages of 175 and 225 mm, the grazing of C4 grass pastures on marginal soils would be possible in at least 40% of the years for 2 and 3 months, respectively. It was concluded that summer-growing perennials are a promising option to alleviate feed gaps on mixed crop–livestock farms in areas with at least 150 mm of rainfall from October to April.

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Crop stubbles are as important for sheep production as annual pastures in the Victorian Mallee

Cited by 8 publications

References 15 publications

Do some naturalised legumes have the potential to improve pasture production in the Victorian Mallee?

Do some naturalised legumes have the potential to improve pasture production in the Victorian Mallee?

Predicting pasture and sheep production in the Victorian Mallee with the decision support tool, GrassGro

Summer-growing perennial grasses are a potential new feed source in the low rainfall environment of southern Australia

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