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. Biomass Solutions manager Alan Wright tells
us about the composting process.
00:48 We process domestic and commercial green waste here at the facility. The green waste
comes in the trucks. It's ground and then loaded into the composting bays. 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. Once
it's been through that process, it comes outside here for natural maturation in those windrows.
And then when it's matured, we put it through the screener and it's 25 mil screen and then
he's sold to growers and the public. We use accredited labs to do 4454 Australian standards
and those that testing's available.
01:43 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 the soil. Compost increases
the water holding capacity of the soil. This means that more rainfall or irrigation is
held in that soil for the plant roots to access. Not only that, but compost particles in the
soil often improve soil structure, increasing root volume. Compost is also teeming with
life, including bacteria and fungi. These diverse soil organisms are vital for transforming
organic nutrients to plant available nutrients, such as nitrogen and phosphorous.
02:29 Other compost properties to know, so that it suits your needs, are particle size,
carbon to nitrogen ratio, and pH. To get high quality compost with no weed seeds, make sure
the supplier provides evidence of the compost temperatures and the nutrient content of the
batch supplied. Something to be aware of when using organic mulches is it can take nitrogen
away from the soil if the mulch is too high in carbon.
02:59 One of the constraints of farmers using compost is the ease of application. New machinery
may allow compost to be applied easier to commercial banana operations on steep slopes.
03:13 The machine's mounted on a truck that is all-wheel drive, and has the ability to
access most sites. The machine has the ability to transfer 12 cubic metres per hour. The
compost can be transferred up to 120 lineal metres from the truck. The machine can apply
all compost and all grades of mulches. We can either pre-load offsite or use a Bobcat
or a frontend loader to load onsite.
03:49 Paul Inderbitzen is a banana grower from Queensland. Here, he tells us about his
views on compost and how he uses it on his farm.
03:58 We've been using compost for the last 10-15 years now, because we think it's a great
way of getting organic matter onto the block, and also it's a really great mechanism for
getting biology to your soil, and also basically improving soil carbon. The best benefit is
the increase in soil carbon. That's the aim of it all. The second benefit is water retention
through the addition of all that extra organic matter. We believe we're getting a better
moisture holding capacity in the profile.
04:42 The other benefit is we've been able to slightly reduce our chemical fertiliser
input. Our compost, we make it ourselves. Our standard recipe is third ratio of each,
tree waste, manure, chook manure, cow manure, pig manure, whatever we can get our hands
on, whatever's available, and grass or [be-gas 00:05:10] or something like that.
05:12 Look, we apply the compost using just a normal everyday belt spreader. We've gone
through many different spreader configurations but for us, it works for us and in our situation,
just a belt spreader is sort of straight forward and simple. Belt brings it out the back onto
two spinners and it just side discharge underneath the bananas.
05:33 There's been no problems using compost. The compost we use is a really, we like to
think we do the compost well. It's a well matured compost. We haven't seen any adverse
effects with it, no.
05:48 In March, 2017, torrential rainfall fell on the banana trial as a result of Cyclone
Debbie. After returning to the site, it was pleasing to see much of the compost still
in place, and not washed away by the rain. Throughout the trial, monitoring of soil nutrients,
plant nutrients, and moisture availability were undertaken.
06:14 Monitoring of the trial showed that compost increased organic matter, increased
soil pH, and increased zinc and potassium levels. Plant parasitic nematode numbers dropped
under the compost treatments and the compost also protected the soil from erosion during
two severe rainfall events. Suckers that emerged during the trial tended to be taller under
the compost treatments.
06:39 The compost blower could apply compost to steep slopes, however, the process was
time consuming. Further investigation is required to develop better techniques to gain advantage
of the benefits of compost.