IRRIGATION ▶▶▶
REMOTE SENSING Satellite imagery can be used to measure crop growth, crop water use, evapotranspiration and evapotranspiration deficits and there are services that supply information through a web-based platform, enabling farmers to adjust their water application accordingly. Similarly, drones with hyperspectral, multispectral or thermal sensors onboard can pick out dry areas in fields and alert growers to the need for extra water, reducing crop stress and yield loss as a result.
3 DRIP IRRIGATION Drip irrigation is probably the most efficient method for delivering water to crops with minimal waste. Drip systems can reduce water usage by between 30% and 70%, but less than 2% of irrigated land employs the technology. Growers seem to be put off by the high
initial cost and plastic waste generated by using trickle tape, but the advantages are clear – it reduces evaporation and water and nutrients can be delivered right where they are needed at root depth. A system being developed by Israeli
company Netafim and Bayer CropScience called “DripByDrip” will also allow crop protection products to be delivered with the water and nutrients, helping reduce any environmental impact of using pesticides.
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4 VARIABLE-RATE IRRIGATION Centre-pivot or linear irrigation methods have traditionally applied a blanket application across the watered area, but as soils can vary considerably, too much or too little water can be applied, hindering crop performance and increasing soil erosion risk. Variable-rate technology for these
irrigation systems can combine soil type data collected using electro-conductivity scanners, yield maps and any other field information to create variable rate irrigation prescriptions. These prescription maps are then uploaded to the irrigator’s electronic GPS controller and the prescribed amount of water applied to each zone as it moves, adjusted by either pivot or linear speed, or by turning nozzles on or off using control valves across the span of the irrigator.
▶ FUTURE FARMING |9 November 2017
5 MONITORING There are many options on the market that allow real-time monitoring of soil moisture and weather, helping growers make better irrigation-management decisions. Using soil moisture probes at multiple depths in the crop’s root zone and “hyper- local” data from weather stations, both fed back to a web interface, allows growers to maintain optimum soil moisture levels, reducing overwatering and associated problems, including leaching, plant stress and yield loss. Such systems also allow farmers to
control their irrigation remotely, switching pumps and pivots on and off through the office computer or from smartphones or tablets anywhere in the world. This optimises water use and cuts labour costs.
REX/SHUTTERSTOCK
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