Growing blueberries using recycled organics


00:10 Almost half of household waste destined
for New South Wales landfills consists of food and garden organic waste. Space in landfills
is rapidly running out, and burying organics is a waste of a valuable resource. While many
facilities are not taking this food and garden waste and turning it into valuable compost,
some are, and this compost has potential to benefit commercial horticultural systems.
Biomas Solutions Manager Alan Wright tells us about the composting process. 00:47 We process domestic and commercial green
waste here at the facility. The green waste comes in in the trucks. It’s ground and then
loaded it into the composting bays. It takes about 21 days for the material to go from
one end of the composting bays to the other. In that time it sits at around about 60, 65
degrees at about 45 to 50% moisture content. 01:14 Once it’s been through that process,
it comes outside here for natural maturation in these windrows, okay? Then when it’s matured,
we put it through the screener, and it’s 25-mil screen, and then it’s sold to growers and
the public. We use accredited labs to do a 4454 Australian standards, and that testing
is available. 01:42 Justine Cox is a soil scientist at the
New South Wales DPI and has over 15 years experience with compost. Here she tells us
about the properties of compost. 01:54 Good quality compost provides a variety
of benefits to soil. Compost can increase the water-holding capacity, which means that
more rainfall and irrigation is held in the soil for the plant roots to access. Compost
helps improve soil structure, improving conditions for root growth. Diverse soil organisms in
the compost, such as bacteria and fungi, are vital in making nutrients, such as nitrogen
and phosphorus, more available to plants. Compost has been shown to reduce the impacts
of phytophthora in some crops. 02:32 One of the constraints of farmers using
compost is the ease of application. 02:39 The truck is an all-wheel-drive truck.
It has the ability to access most difficult sites. It pneumatically applies the material
through a four-inch hose. The machine can apply up to 12 cubic metres per hour, depending
the situation and the application that it’s being used for. From the truck location, we
have the ability to blow material up to 120 metres. The machine has the ability to blow
all grades of compost as well as all sizes and all grades of hardwood and pine mulches.
We can either preload offsite or use a Bobcat or a front end loader to load onsite. 03:33 Where access is good, belt spreaders
can also apply recycled organics very quickly. 03:41 So we’ve got a Seymour mulch spreader.
It’s about a four cubic metre capacity. What happens is that there’s a walking floor on
the bottom, and it moves the material onto a conveyor, which then applies it to the inter
row. If we were applying composts with the side throw spreader, the compost would need
to be of a fairly fine consistency and not too sticky so that it moves freely out of
the conveyor. It handles wood chip of all different sizes fairly well, but the smaller
and finer the material, the better it seems to handle it. 04:17 The differences we’ve been able to see
with the compost and the wood chip is that, particularly on this block because the trees
are older and much bushier than the rest of the farm, they do tend to use a little bit
more nitrogen, and we do have issues with nitrogen deficiency in this block. But the
lines where the compost was applied seem to have less yellowing of the leaves in the middle,
which is where the nitrogen deficiency first shows itself. Subsequent soil tests showed
that there was actually more available nitrogen in the soil on those lines with compost. 04:49 The only reason we apply the wood chip
is for weed suppression. We have moved away from using wood chip actually now to using
a plastic weed mat because we think we get better weed control. Wood chip, you need to
reapply it every year or every second year depending on how thick it’s applied, and it
doesn’t quite give as good weed control as what the plastic does. It does seem to leach
away some nitrogen from the plants as well. 05:16 Russ Glover is an owner of the blueberry
farm whose property this trial is being run on. He shares his views on the recycled organics
trial. 05:26 Well, the trial here is to actually
work out how effective using compost and hardwood chip is in the commercial growing of blueberries.
I want data, reliable data, that can actually tell me in a commercial sense whether or not
it’s worth using the compost, whether it’s worth using the hardwood chip or a combination
of both compared to the conventional type of growing systems we’re actually using for
blueberries at the moment. 05:57 For me, using compost is actually increasing
soil health by adding organic matter to the soil, which in turn leads to better water
retention. We’re looking at how it will suppress weed growth on the actual mounds of growing
blueberries, but overall improving soil health. 06:17 Well, there is definitely a market advantage
in growing blueberries organically along with all other fruits that are growing organically.
We’re not pressured about growing organically. We need to have a system that works best from
a commercial point of view that’s good for both the grower and the consumer. I’m hoping
that we will have both a reduction in the costs associated with growing blueberries
and an increase in the actual profitability of growing blueberries. 06:47 Throughout the trial, monitoring of
soil nutrients, plant nutrients and moisture availability was undertaken. 06:56 Monitoring of the trial showed that
the compost increased organic matter, increased the cation exchange capacity and also reduced
soil sodicity. So moisture was higher under the wood chip than under the weed mat treatment.
Soil and leaf nutrients should continue to be monitored as compost does not address all
existing nutrient limitations.

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