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Growers have been doing a number of things to adapt and mitigate against the effects
of drought and extreme heat events, that being putting out the completely netted orchard,
that being improving their irrigation management, trying to cut back on the amount of irrigation
they apply. In some cases growers have actually installed overhead irrigation to try and cool
the fruit. Some growers have been using mulch on the soil surface to stop surface evaporation
and then some growers have even been using a calanite spray to help reduce sunburn on
the fruit as well.
In most cases mulch can work very well in suppressing the water loss in the soil surface
and enhancing the uptake by the vines, not only just by suppressing, but it can also
improve soil properties as well. So water that is actually being applied to the soil
is infiltrating better and is being made more available through the soil biology and being
more active and having better root activity.
It can be quire costly so do not necessarily think you need to apply it right across the
farm, just think about spots on the farm where you can, where you think you might get the
best benefit from it and just apply it in those areas. Do your own little trial on the
farm.
Good irrigation management obviously reduces the amount of irrigation required by the orchard.
Growers have been adopting dripper irrigation strategies and the idea of those drippers
irrigation strategies is obviously to save water. Water is very expensive, it has been
very expensive for the last few years and if growers can actually cut back on the amount
of irrigation they need to apply then of course they are going to save that little bit of
money.
Since the drought or the reduced allocations that both Victorian and New South Wales and
South Australia have experienced, irrigation management has taken another step. You know
we had a 50% cut in our first year in New South Wales and it really forced growers who
were remaining in the industry to improve their practices and [Inaudible 00:02:15] a
little critically at the way they use their water and we always had a great adoption of
technology, or we thought we did, but it lifted again to a greater level and that adoption
of technology is now virtually standard practice.
Good trellising and canopy management, what that does is it actually improves productivity
in the orchard. It does not necessarily have a direct impact on drought and heat, but good
canopy management within the orchard actually means that the productivity of that orchard
will be high. In any orchard it will do a few things, it will help prevent obviously,
prevent hail, it will lower the temperature of the fruit, it will stop sunburn, direct
radiation on the fruit, it will save water and there will also be a reduction in the
amount of rub of the fruit from wind damage.
We can sit out here and farm outside and that and the birds can get us, the hail can get
us, the sun can get us, the wind can get us, the bugs can get us, we can irrigate more.
By putting that up you can take some control over the destiny of your factory. It is terribly
expensive to put up, why would you do it? Because you consistently want to grow fruit
every year. It has got to go over the things that are high return, it has got to go over
things that are high yield. Those are the parts of my orchard that make my orchard continue
to operate. So if it is a low yield, poor return variety, I am not going to put net
over it.
When I get asked about, you know "isn't it expensive to spray for sunburn, by using sun
protectants", you know I am not so concerned about the cost of that particular material.
The real cost in the orchard is all the labour that has gone into that crop to that point.
If I can prevent a percent of sun damage, through any particular heat event, a percent
of 400,000 apples is 4,000 apples, that is all that I have got to save and I have probably
paid for the use of the protectants. So it is about income maximising, not cost reduction.
There is no silver bullet, just because I have put a net, that up does not stop sunburn,
just because I put Callan clay or calcium carbonate or carnu wax on, does not eliminate
sunburn. The things work in layers, that is lines of defence. When you are trying to combat
environmental issues its layers of defence are superior to any one particular technique.
Some of these research areas that we are investigating can be trialled by growers and bad things
like the effects of water deficits during the season on file are nutrient concentration
in the fruit. That is quite an easy area of work that a grower could actually implement
on a small section of a row. For example cutting back on the irrigation and looking at the
response of those trees. Other things like netting, it is much more difficult for a grower
to trial that. It is probably better if he actually makes a decision based on the benefits,
the economic benefits of building a structure. I also think that there is a big opportunity
for us to improve the forecasting of extreme events, so the growers can actually implement
management based on those good forecasts of extreme heat events.
If you want to know more about this programme, contact your industry grower association or
the DPI customer service line - 136 186.