Ground Cover Supplement : GC Supplement - Water use efficiency
GROUND COVER WATER USE EFFICIENCY 22 Water determines a farm's capability As water use efficiency drives the whole system, it can be much more than a benchmark for crop inputs POTENTIAL YIELD BASED on water use efficiency (WUE) has traditionally been a method of determining fertiliser inputs. With the high seasonal variability experienced in the past decade, consultant Ed Hunt sees greater value for the WUE benchmark. He is working with grower groups in low-rainfall regions and using WUE as a benchmark for the level of debt a property can carry, as well as input management. In parts of the Mallee, growing- season rainfall (April to October) has been about 60 per cent of average for the past five years. Prior to this many growers have converted to intensive or continuous cropping systems. Working with a grower's own figures, Mr Hunt is looking to establish a farm's capability and determine which are the most profitable systems. "In low-rainfall regions we have seen neighbours using very different no-till systems -- one with knife points and conventional row spacing, another with inter-row seeding with discs and wider row spacing -- achieving very different yields. But which is more profitable?" Mr Hunt asks. "We need to look at the cropping mix, rotations and production systems and put these in the context of profit, debt and risk, not just in terms of yield and gross margin." As the name implies, variable inputs change with the number of hectares cropped or yield predicted. However, fixed costs such as interest do not change, even if the season determines that less area should be farmed. "The objective of this project is to improve growers' business skills and to encourage them to use changes in profit as the driver of their businesses, rather than changes in yield or turnover," Mr Hunt explains. In collaboration with University of Melbourne economist Bill Malcolm, each grower's figures are being analysed to establish how much investment in land and equipment, and how much debt, a business is capable of sustaining. Mr Hunt acknowledges there is no perfect system, but says that by running the production and financial figures for a range of scenarios a grower can identify the financial scenario with which they are most comfortable. "It is all about understanding risk: how much risk individuals are prepared to carry, how much a business can carry and how this relates to debt load. "In a nutshell, higher-risk systems should generally be established based on less debt than lower-risk systems." Mr Hunt is keen to emphasise the importance of sound foundations for this project. To ensure the processes are appropriate and correct he is working with a pilot group of growers associated with BCG (formerly the Birchip Cropping Group) in Victoria. In future he will be working with growers associated with the Minnipa Agricultural Centre in South Australia. In another project, Victor Sadras, from the South Australian Research and Development Institute, and Richard Routley, from Queensland Primary Industries and Fisheries, aim to establish a farm business design to improve whole-farm WUE. Whole-farm WUE ($/mm/ha) measures the performance of the farm business. It is proposed that improving the allocation of resources (water, fertiliser, land, labour, machinery, managerial skill and time) among alternative farm activities is likely to improve whole-farm WUE. Using the bio-economic model APSFarm, the effect of allocation of farm resources on whole- farm WUE, profitability and economic and environmental risk will be tested. The project is working in collaboration with individual farmers, and with Central Queensland Sustainable Farming Systems, Central West Farming Systems (CWFS) (NSW) and the Hart Field Site Group (SA). In central Queensland the issue of cropping intensity is being investigated. Three outcomes are anticipated from increasing cropping intensity: reduced yield average of individual crops; reduced unproductive water loss (that is, runoff and deep drainage) and increased whole-farm WUE; and increased economic risk. In SA, whole-farm WUE is being compared in the contrasting rainfall environments of the Mallala and Spalding districts and the impact of management strategies is being assessed, including the use of legume break crops in cereal rotations and the inclusion of hay crops in the cropping system. The focus of the CWFS case studies is still to be determined. □ GRDC Research Code DAS00089 More information: Edmund Hunt, 08 8628 9028, email@example.com; Associate Professor Victor Sadras, SARDI, 08 8303 9661, firstname.lastname@example.org FARM CAPABILITY How much debt a farm is capable of sustaining relates to productivity. WE NEED TO LOOK AT PRODUCTION SYSTEMS IN THE CONTEXT OF PROFIT.
GC Supplement - Wheat breeding
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