Empirical models to quantify the nutritive characteristics of annual pastures in south-west Western Australia
A. G. T. Schut A B D , S. G. Gherardi C and D. A. Wood CA Department of Spatial Sciences, Curtin University of Technology, GPO Box U1987, Perth, WA 6000, Australia.
B Cooperative Research Centre for Spatial Information, 723 Swanston Street, Parkville, Vic. 3052, Australia.
C Department of Agriculture and Food Western Australia, Locked Bag 4, Bentley Delivery Centre, WA 6983, Australia.
D Corresponding author. Email: t.shut@curtin.edu.au
Crop and Pasture Science 61(1) 32-43 https://doi.org/10.1071/CP08438
Submitted: 10 December 2008 Accepted: 16 October 2009 Published: 17 December 2009
Abstract
The objective of this paper is to quantify the magnitude of the major sources of variation, which affect in vitro digestibility (DMD) and concentrations of neutral detergent fibre (NDF), acid detergent fibre (ADF), and crude protein (CP) of annual pastures in Mediterranean-type climate zones. Four experiments were conducted in the south-west of Western Australia in 2006–07 and 2007–08, where the supply of nitrogen, phosphorous, potassium, or sulfur and pasture types were varied. Effects of seasonality, fertiliser application, pasture type, and site were analysed with an auto-regression maximum likelihood procedure. Temperature sum was used to explain the seasonal differences in DMD, CP, NDF, and ADF. Seasonality explained 82, 79, 79, and 62% of the total variation in DMD, NDF, ADF, and CP, respectively, with only an additional 5, 5, 6, and 24% being explained by the combined effects of site/management, fertiliser application, and pasture type. The differences in DMD, NDF, ADF, and CP, between sites, were 2.3–6.0%, 4.6–18.7%, 5.8–8.6%, and 1.5–17.4%, respectively. Pasture types differed by 6.6–9.5%, 9.0–11.4%, 3.1–6.1%, and 5.1–5.2% for DMD, NDF, ADF, and CP, respectively. The differences between sites and pasture types were markedly larger for CP, NDF, and ADF than for DMD. Fertiliser application did not affect nutritive characteristics, with the exception of N application rates on CP. It was concluded that the seasonality model captured nearly all of the temporal variation in DMD, NDF, and ADF but not in CP. The spatial variation in DMD was mostly determined by pasture type. By comparison, NDF and ADF were most strongly affected by grazing management, and CP by the availability of N.
Additional keywords: feeding value, nutritive value, nutrient concentration, legumes, grassland.
Acknowledgments
We thank the CRC for Spatial Information for funding this work. We acknowledge the in-kind support of CSBP Limited (WA) for soil analysis and fertiliser supply recommendations, CSIRO Livestock Industries for their in-kind support in analysing pasture samples, and the Department of Agriculture and Food Western Australia for providing trial sites, and technical and financial support. We thank Mrs Elizabeth Hulm for her expertise and work in laboratory analysis, Dr Jane Speijers for her valuable advice on statistical analysis, and two anonymous reviewers for their valuable comments and suggestions.
Callow MN,
Michell P,
Baker JE, Hough GM
(2000) The effect of defoliation practice in Western Australia on tiller development of annual ryegrass (Lolium rigidum) and Italian ryegrass (Lolium multiflorum) and its association with forage quality. Grass and Forage Science 55, 232–241.
| Crossref | GoogleScholarGoogle Scholar |
Cayley JWD,
Saul GR, McCaskill MR
(2002) High-fertility pastures in south-west Victoria can be economically and environmentally sustainable. Wool Technology and Sheep Breeding 50, 724–729.
Elliott DE, Abbott RJ
(2003) Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, South Australia. 1. Pasture mass, composition and nutritive characteristics. Australian Journal of Experimental Agriculture 43, 553–577.
| Crossref | GoogleScholarGoogle Scholar |
Gierus M,
Jahns U,
Wulfes R,
Wiermann C, Taube F
(2005) Forage quality and yield increments of intensive managed grassland in response to combined sulphur-nitrogen fertilization. Acta Agriculturae Scandinavica. Section B – Soil and Plant Science 55, 264–274.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
Heinz DC, Chang CI
(2001) Fully constrained least squares linear spectral mixture analysis method for material quantification in hyperspectral imagery. IEEE Transactions on Geoscience and Remote Sensing 39, 529–545.
| Crossref | GoogleScholarGoogle Scholar |
Henry DA,
Simpson RJ, Macmillan RH
(2000) Seasonal changes and the effect of temperature and leaf moisture content on intrinsic shear strength of leaves of pasture grasses. Australian Journal of Agricultural Research 51, 823–831.
| Crossref | GoogleScholarGoogle Scholar |
Justes E,
Mary B,
Meynard JM,
Machet JM, Thelier Huche L
(1994) Determination of a critical nitrogen dilution curve for winter wheat crops. Annals of Botany 74, 397–407.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
McIvor JG, Smith DF
(1973) Plant factors influencing the nutritive value of some temperate pasture species. Australian Journal of Experimental Agriculture 13, 404–410.
| Crossref | GoogleScholarGoogle Scholar |
Moore AD,
Donnelly JR, Freer M
(1997) GRAZPLAN: Decision support systems for Australian grazing enterprises. 3. Pasture growth and soil moisture submodels, and the GrassGro DSS. Agricultural Systems 55, 535–582.
| Crossref | GoogleScholarGoogle Scholar |
Rossiter RC,
Collins WJ, Klein L
(1985) Winter growth and nutritive quality of Serradella (Ornithopus spp.). Australian Journal of Experimental Agriculture 25, 362–366.
| Crossref | GoogleScholarGoogle Scholar |
Ru YJ, Fortune JA
(2000) Variation in nutritive value of plant parts of subterranean clover (Trifolium subterraneum L.). Australian Journal of Experimental Agriculture 40, 397–403.
| Crossref | GoogleScholarGoogle Scholar |
Ru YJ, Fortune JA
(2001) Seed yield and nutritive value of dry, mature subterranean clover (Trifolium subterraneum L.). Australian Journal of Experimental Agriculture 41, 169–175.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
Schut AGT,
van der Heijden GWAM,
Hoving I,
Stienezen MWJ,
Van Evert FK, Meuleman J
(2006b) Imaging spectroscopy for on-farm measurement of grassland yield and quality. Agronomy Journal 98, 1318–1325.
| Crossref | GoogleScholarGoogle Scholar |
Vickery PJ,
Hill MJ, Donald GE
(1997) Satellite derived maps of pasture growth status: association of classification with botanical composition. Australian Journal of Experimental Agriculture 37, 547–562.
| Crossref | GoogleScholarGoogle Scholar |