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Improved potential yield estimates for farmers and advisers

Tennant, D. Dr; Ph: (08) 9368 3287; Fax: (08) 9368 3355

Research organisation: Agriculture Western Australia, 3 Baron Hay Court, South Perth WA 6151

Sponsors: GRDC-WA, Grains Research and Development Corporation: WA State Committee

Objectives:

1. To provide more robust estimates of crop water use for use with the French and Schultz formula;

2. To develop French and Schultz formulae for use with barley, lupins, peas and other crops;

3. To extend the French and Schultz formula to account for location and season differences in environmental demand for water.

Methodology:

French and Schultz equations derived for wheat in South Australia (French and Schultz 1991) were based on crop water use measurements made over a minimum of ten years. The alternative to doing this with lupins, barley, peas and other crops is to estimate water use for those years and sites for which good yield data are available. Existing procedures to estimate water losses through evaporation, run- off and drainage will be used to develop a procedure for estimating soil water storage at planting. Simple estimates of crop water use can then be made by estimating soil water storage at planting, and adding on rainfall between planting and maturity. If necessary, better estimates can be made using one of several water balance models that are available (Greacen and Hignett 1976, O'Leary et al. 1985, RESCAP and CERES-wheat). In the first year of the project, field work will focus on measuring soil parameters (hydraulic properties, waterholding capacities, evaporation limits and rates) at sites for which yield data are available for lupins, barley, peas and other crops, to run one or more of the models to estimate soil water storage at planting and/or crop water use. In the second and third years, the programme of measuring soil properties will continue; and water use, dry matter production and yields of wheat, lupins, barley, peas and other crops will be measured at sites in the northern, central and southern coast regions (3 sites per year).

French, R.J. and Schultz, J.E. (1984). Water use efficiency of wheat in a Mediterranean-type environment 1. The relation between yield, water use and climate. Australian Journal of Agricultural Research 35, 743-764.

Greacen, E.L. and Hignett, C.T. (1976). A water balance model and supply index for wheat in South Australia. Division of Soils Technical Paper No. 27, CSIRO, Australia.

O'Leary, G.J., Connor, D.J. and White, D.H. (1985). Effect of sowing time on growth, yield and water-use of rain-fed wheat in the Wimmera, Vic. Australian Journal of Agricultural Research 36, 187-196.

Progress: In work reported to this point, attention has focused on developing better procedures for estimating stored water and crop water use (First Project Aim). Emphasis has focussed on accounting for water losses through evaporation in stored water estimates. Run-off and drainage functions and effects of limited water storage capacity in soils will be explored in later work. Work undertaken to meet other project aims have included a start to accumulating rainfall and yield data to develop French and Schultz equations for crops other than wheat (Second Project Aim); and field work in collaboration with K. Regan and D. Abrecht (GRDC project): Significance of early maturity in improving grain yield and water use efficiency in wheat) to measure water use and dry matter production of wheat at Mullewa and Merredin, to develop criteria to account for effects of location and season differences in environment demand for water on dry matter production and yield (Third Project Aim).

Period: starting date 1992-07; completion date 1995-12

Status: completed

Keywords: crop yields, water use

Publications:

Regan, K.L., Siddique, K.H.M., Tennant, D. and Abrecht, D.G. (1993). Early maturity improves grain yield and water use efficiency of wheat in low rainfall regions of Western Australia. Proceedings of the 7th Australian Agronomy Conference, Adelaide, 1993, pp. 286-89.

Regan, K.L., Siddique, K.H.M., Tennant, D. and Abrecht, D.G. (1996). Grain yield and water use efficiency of early maturing wheat in low rainfall Mediterranean environments. Australian Journal of Agricultural Research 47, 595-603.

 

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