Water use and pumping costs
'Our vineyard is a work in progress, however there are indications that water use has been reduced from three megalitres/hectare/year to one megalitre/hectare/year,' Ken Eckersley from the Nicholson River Winery said.
The new irrigation system is easy to install as it is comprised of readily available plumbing components.
The property has been producing wine for almost 30 years and relies on irrigation to help supplement the variable 663mm rainfall at Nicholson, in East Gippsland.
The Nicholson River Winery has been using trickle irrigation for that time. The first vines planted relied solely on rainfall. This enabled them to establish a deep root system. 'They are still producing the best fruit on the property,' Ken said.
Jeff Paterson, Peter O'Keeffe and Ken Eckersley of the Nicholson River Winery won first prize in the 2010 Southern Rural Water Waterwise award for groundwater users for their work in installing a new generation of drip irrigation. The judges commended the system as being highly adaptable to other forms of agriculture.
Over time, however, rain became scarcer and surface drip irrigation was installed.
Nicholson Irrigation System (NIS)
The new vines grew but under performed. Extended drought coupled with competition from summer grasses and less than optimal watering created plants with limited root development. These plants were also often diseased.
This situation led Peter and Jeff to suggest to Ken that they combine conventional drippers, that deliver water directly to the plant roots, via PVC pipe.
This has since developed into what they call the Nicholson Irrigation System (NIS). This is a system that delivers water directly to the plant roots, is long lasting and ensures leaks and blockages are easy to fix.
The NIS combines the transparency of surface drip irrigation and water savings through reduced evaporation and competition from summer grasses that subsurface irrigation provides. The NIS does this by using 13mm or 19mm irrigation lines with pressure compensation drippers that are located at each vine and drip inside a 40mm PVC pipe.
Installation involves using a post hole drill to dig to a depth of about one metre, to loosen the soil below the PVC pipe. This is about half a meter below the end of the PVC pipe, to allow water to freely flow into the soil.
Gypsum can be added to clay soils to help improve soil structure during installation and to also help with water penetration. The 60cm PVC pipe is then inserted into the ground with 10cm exposed above ground. The base of the PVC pipe is cut on an angle to reduce blockages during installation.
NIS and its effects
The main aim for the NIS is to deliver water directly to the plant's root zone rather than to the ground surface. 'Because water is delivered directly to the plant roots, there is a reduction in evaporation and losses to competing grasses,' Ken said.
Plant roots are also able to go deeper rather than staying near the surface of the water source. 'The PVC pipe directs water into the root zone where the plant can use it; there is no wastage,' Ken said.
Measuring soil moisture
The introduction of the NIS on the property has also been complemented with an extensive network of tensiometres to measure soil moisture.
A future plan includes automating the irrigation system with electronic valves and a timing unit, as half an hour to an hour is ample watering time with the NIS system. The original drip irrigation system took six to eight hours per watering.
The NIS also allows a quick response by plants to added fertilisers or fertigation. Nutrients, however, need to be carefully applied to avoid burning the sensitive roots.
NIS and soil types
The NIS also allows for a variation in dripper rates according to soil types. An unexpected benefit from installing the system is that the PVC pipe has provided a habitat for snails to collect in which are then killed by baits.
Water-logging may be a problem with this system in some soil types. Installing the PVC pipe with an angled end, drilling the watering holes deeper than the PVC pipe and adding gypsum into the hole can help to increase infiltration rates. The potential impact of water-logging can also be managed by varying the volume of water delivered to each plant by changing the rate at each dripper based on soil type.
Benefits of installing NIS system
The installation of the new system costs more than in-line irrigation at about $3.50 to $4 per vine. Over half of this is the labour cost. It costs more to retrofit an existing line irrigation system as more labour is needed.
So far the eight hectare vineyard has had half of its 16,000 vines upgraded to receive water through the NIS. 'In times of long-term rainfall decline and rising costs, it can be the difference between viability and a slowly declining vineyard,' Ken said.
Jeff, Peter and Ken believe replanting is a great opportunity to reconsider and apply a new way of thinking. 'There are huge potential savings to be made. In today's climate it's about a quality product which is smart and efficiently produced,' Ken said.
The new Nicholson irrigation system makes better use of a limited water resource and introduces a new generation of drip irrigation.
- The Nicholson irrigation system delivers water savings through shorter watering times, less evaporation and no watering of weeds and grasses between the vines.
- The NIS also results in less use of power and herbicide.