Economics of irrigation system conversion: – big gun irrigation to furrow irrigation sugar

Around Bundaberg, big guns or water cannons are commonly used to irrigate sugarcane. A low-cost alternative is furrow irrigation if field slope and other relevant factors such as soil type, paddock size, access to labour and capital enable conversion. Providing field slope and soil type are suitable for furrow irrigation, economic analysis indicates 13% return on marginal capital to change from big gun to furrow irrigation. Owing to the high costs attributed to pressurised water needed for big gun application, even at sub-optimal irrigation application rates of furrow irrigation, the analysis found the marginal return on capital to remain above 10%.