Design and demonstration of precision agriculture irrigation applied to different vegetable crops
Modification of new and existing technology in agriculture is required to ensure productivity growth and to address issues of climate change and natural resource sustainability. Two key challenges faced by the irrigated agriculture community are (i) competition for increasingly limited water resources and (ii) increases in energy costs. In this project the potential of two retro-fit systems were assessed over three seasons (2010-2012) and included: i) a pressure control system for a travelling gun irrigator; and ii) a variable rate irrigation (VRI) system for a linear move irrigator. Travelling gun irrigators are commonly used in horticulture due to their low capital cost and practicality of use on undulating topography. Modifications to improve the performance of a travelling gun irrigator were under taken as part of a collaborative project between the Tasmanian Institute of Agriculture (TIA) and Seattle Services Pty. Ltd. The retro-fit of telemetry devices and modified irrigation components to a travelling gun irrigator in this project enabled a constant set pressure to be maintained at the gun regardless of slope or length of the irrigation run. Comparisons between modified and conventional travelling gun irrigation were conducted and included monitoring energy and water use, yield, quality and disease assessments in a carrot crop. In 2011 there was a 17-21.8% and 5-10% reduction in energy and water use respectively between the modified and conventional irrigator, with a 10% increase in yield of carrots for the modified irrigator. In addition a collaborative project was conducted between the Tasmanian Institute of Agriculture (TIA), Seattle Services Pty. Ltd. and CSIRO ICT. The aim was to use soil moisture measurements collected in real-time from a wireless sensor network (WSN) provided by the CSIRO ICT, to schedule irrigation events, develop a VRI (developed by Seattle Services Pty Ltd.), and develop a decision support system to enable closed loop site specific irrigation to meet plant water requirements. The two components (VRI and WSN) were independently assessed. The WSN soil moisture system provided data during the second season (2011), however, problems with calibration remained unresolved. The variable rate system operated with water savings of 10-15% over the three cropping seasons. However, high rainfall resulted in reduced irrigation events during the growing seasons and limited the ability to monitor equipment in this trial. The retro-fitted component technology developed in this project demonstrate an innovative approach to address issues of sustainable natural resources management, adapting to climate change challenges and responding to increases in energy costs.