Digital irrigation needed

A simple computer programme to help schedule irrigation on dairy farms could soon be available and judging by the findings of an AgResearch survey, it is badly needed, Rural News reports The Irrigation Calculator has been developed with Dairy Insight and Dairy NZ funding by scientists at Crop & Food and AgResearch.It is designed to help farmers decide when to irrigate, how much water to apply, and the consequences of wrong irrigation timings or amounts, says Dick Martin. Responses to an AgResearch survey* from over 200 dairy farms in Canterbury found only 21% measuring soil moisture, 12% using a scheduling service, and 6% doing water budgets. Monitoring of 10 irrigated dairy farms found only three or four producing close to the maximum potential drymatter, while the remainder had "˜about half as much grass as the best producing farms.'In his experience, Martin says poor pasture management is unlikely to be the major cause of that production loss, but under-irrigation could well be, and where farms are over-irrigating they are wasting energy, water, and possibly leaching nutrients. The calculator will help farmers identify where their irrigation practice sits, and what action, if any, is needed to correct it, he says. The calculator uses input data such as soil type, weather, irrigation amount and frequency to produce a graphic of plant available water over time and figures for potential and predicted production."˜It is very simple. There are only two input screens.'It will also help users decide when to start and finish irrigating, and when, where and with how much to irrigate during the season.