Crop IR Log - an Irrigation Calculator for Tree and Vine Crops

Irrigation supports the biological basis of New Zealand's productive economy and currently comprises about 75% of the nation's consumptive water use. Tools to monitor, audit and predict crop water use are needed to maximise the economic benefit from our finite water resources. In addition, international standards for water use are being developed (www.waterfootprint.org) so our primary industries will increasingly need to show that their use of water is sustainable. In this paper, we describe the development Crop IR Log, an irrigation calculator for tree and vine crops. This software uses a web-based interface to access daily values of evapotranspiration and rainfall, plus a 10-day forecast, in order to provide real-time irrigation recommendations for orchardists and viticulturists. The calculations are based on crop factors derived from heat-pulse measurements of sap flow, and soil hydraulic properties derived from profile descriptions of texture and stone contents. We compare Crop IR Log calculations against grower's soil moisture data from peach, apple and kiwifruit orchards and a grape vineyard. This measurement and modelling comparison is a very important step in developing a tool that will provide growers with high quality recommendations for irrigation application.