Executive Summary
Within an overall framework of promoting sustainable farming, MAF Policy has designed a research program with the aim of developing procedures to achieve sustainable irrigated agriculture and to have those procedures adopted and used by the New Zealand farming industry.
In previous studies funded through the MAF Operations Research Programme, a set of indicators that farmers could use to measure and report on the sustainability of their irrigation management practices was determined (MAF Technical Paper 00/03), and Best Management Guidelines for Sustainable Irrigated Agriculture developed (MAF Technical Paper 00/05). The implementation of the Best Management Guidelines was tested in the 1997-1998 irrigation season (MAF Technical Paper 00/06) to find out if they were workable, sensible, and could be adopted by farmers.
The ability to test the Best Management Guidelines was restricted to a significant extent by an unexpected very early start to the irrigation season, an unseasonably hot and dry summer, unexpected difficulties with flow measurement and delays in equipment supply.
The primary objective of this project was to continue testing the Best Management Guidelines developed in the 1996/97 year, again to find out if farmers could adopt the concepts to demonstrate and improve irrigation performance. The aim was to operate the programme for a full irrigation season, and to resolve some of the difficulties experienced in the previous year.
The previous three Canterbury farms were selected for continuation of the project because of the interest shown by them in the 1997/98 season, and because some of the monitoring equipment had been installed. The three farms were a dairy farm using border-strip irrigation, a dairy farm using spray irrigation (centre-pivot), and a cropping farm using spray irrigation (rotating
The work program included installation of remaining soil moisture and flow measuring equipment, monitoring farmer data collection and analysis, providing on-going liaison and refinement of the system, and calculating end of season indicators.
Despite some difficulties with short battery life on some of the monitoring equipment, and with moisture getting into the flow meters, sufficient data was obtained for all farmers to make good irrigation management decisions. Once again, an extremely dry irrigation season reduced the need for frequent decision-making in the peak of the season. The main objective during peak times was to keep the irrigation running to try to keep up with irrigation demand.
Total seasonal water use for both dairy farms and seasonal water use for the two crops monitored on the cropping farm was calculated. In addition, percentages of water stored in the crop root zone, which give an indication of irrigation efficiency, were calculated.
The project has clearly shown that the process of planning, doing, monitoring and reviewing, given suitable resources, will not only improve irrigation performance, but will also provide supporting information to illustrate that performance.
All three farmers used the system to good effect, and now have benchmark indicators that they can use to compare subsequent year’s performance against. The farmers have information to identify where changes in irrigation management could be made to improve overall water use efficiency without compromising production.
The most important outcome of the project is that the concept of measuring field data and calculating indicators to make short-term and long-term irrigation decisions is workable and sensible. If adopted by farmers, irrigation performance, both in terms of profit and in terms of minimising environmental effects, can be improved and the overall goal of sustainable irrigated agriculture achieved.
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