NZ Dairy Winter 2021

104 | nz dairy Efficient irrigation systems a must IRRIGATION NZ » Smart Irrigation E ven though we are now well into the wet season, foremost in Canterbury the major rain event at the end of May will be one for the re- cord books, our thoughts are with those still facing the clean-up and infrastructure damage. However, in the broader view of climate change impacting our sector and the extremes of dry to wet, we are all too aware we have only just come off the back of a significant drought year for most regions of New Zealand. Some near Ashburton had only recently shut down their irrigators having run late into the Autumn. In anticipation of continued climate change extreme events placing demands on soil moisture management, we must keep our eye on water resource efficiency and how that helps us meet our business, environmental and community objectives or expectations. Efficiency, reliability, and effectiveness are often used interchangeably when looking at irrigations systems and your point of perspective has an influence on what you need to focus on. Extracting water from surface flows or underground water reserves places obligations on the irrigator through consent conditions. The rate of take and sometimes annual volumes, along with time frames define the limits under which we operate. Farming within these limits is the subject of much discussion around the farm breakfast table when considering utilising irrigation from the toolbox available to food and fibre producers. You may look at the efficiency of the volume of water you extract in terms of how much of that reaches the roots of the plants you are growing, whether grass, fodder, arable or horticulture. You need to be looking to identify any weak points in your process that allows losses or inefficiency that means the water is not as effective as it could be. While it is easy to look at your infrastructure for signs of leaks or losses the real gains are not as easy to see. A keen interest in your soils across your irrigated land is necessary, literally digging into this topic so you understand the characteristics and variability of what you have to work with. Your aim as an irrigator is to use just enough water applied through your equipment to keep the soils at its best moisture content down through the depth of the root zone. Make sure you under- stand what that rooting depth is and how the soils changes down the profile. Think of it like a sponge, or even a stack of different sots of sponges, that each have an ability to hold water that is made available to the roots, but only to a point. The result of too much water applied to satu- rated soil means it simply flows out the bottom of the root zone and its effectiveness will be lost, along with the time, energy, and money you used to get it to the paddock. Or if the soil is too wet the water Stephen McNally (inset), prinicipal technical advisor at Irrigation NZ says irrigators should be using just enough water applied through their equipment to keep the soils at its best moisture content down through the depth of the root zone. • to page 106 may not even penetrate and flow across the surface or pond. A saturated soil where all the large pores spaces are overfilled with water prevents oxygen getting to the actively growing and respiring root tips where most of the water and nutrient update is occurring. The linkage between what water you can use and the water that is needed in the soil root zone, is your irrigation equipment, the pumps, filters, pipes, and emitters, whether those are pivot irrigators or under tree sprinklers. Each part of this equipment’s pathway from source to soil, presents opportunities for precision and efficiency. The Bucket Test app that incorporates a simple process of capturing water underneath your irrigation system gives you a very quick indication of the uniformity of distribution. If the distribution patterns across the system is poor you are likely overwatering some parts of the soil profile, with a risk of leaching nutrients, and underwatering others leading to low growth areas. Specialist suppliers of irriga�on equipment Pivots and laterals Variable rate irriga�on for pivots and laterals Hoses & accessories Couplings & fi�ngs Hard hose irrigators Pumps and motor pumps Generator sets Engine protec�on Rain guns and booms Intelligent controls for all irriga�on machines 0800 65 55 45 www.bayirriga �on.co.nz 15 Barnes Place, Has�ngs Intelligent, dependable irriga�on systems that last