(COUNTRY MUSIC PLAYS) NARRATOR: Until recently,little was known about the viability
of pasture croppingin Western Australiadue to the lack of local research
and on-farm experience.At this focus site south-west
of Moora, staff from CSIROand the Department of Agriculture
and Food Western Australiaare evaluating the viability
of pasture croppingacross sub-tropical
perennial grasses in WA.The site was established in 2008to collect detailed measurements
on the soil water dynamicsand crop performance of
different pasture-cropping systems.At this site, we’ve grown barley
in rotation with lupins for the last four years. Here’s Wonga lupins
sown into Gatton panic. We’re interested in exploring
not only the logistics of seeding a crop into a perennial, but also how it performs
in terms of yield.Even though the period
of active growth for the annual cropand perennial pasture
are at different times of the year,there could be some overlap
and competitionaround the break of season
and in spring.The key thing we’re doing at this site is measuring the soil water uptake
by the two different components. So we’ve got the pasture
and we’ve got the crop and we want to know
where in the soil they’re getting their water from and what time of year they’re doing it so that we know
how they’re mixing it up together. And one of the ways
we’re measuring soil water is with these FDR probes. They’re about 30cm long
and just go into the soil and, yeah, you can program them to measure soil water
every 15 minutes. And we put them in
at different depths into the soil. We can really look at day by day
and hour by hour where in the soil the different
components are getting water from.Soil moisture readings over timehave shown that the amount
of stored moistureunder the annual crop and
pasture cropping treatment differ.Interestingly, the amount of
stored moisture in the soil profileduring the winter growing season
is similar.By contrast, the amountof soil moisture in summeris about 100mm lessunder pasture croppingcompared to
the annual crop treatment,down to a depth of 3m.Greater depletion of soil moistureunder pasture cropping systemsoccurs in summer,
during the periodof active perennial growth.This lifts groundcover,provides green feedand creates a larger ‘bucket’to reduce recharge
after heavy rainfall events.But what impact
does this have on grain yield?The key result we’ve got so far is that over two years of growing
crops and pastures together, the crop yield
has been much the same whether we’ve had the pasture
growing or not. So we’re not seeing
anywhere near the yield penalty that we thought we would.For the past four years,the performance of annual cropsown over different
perennial pastureshas been compared with
an annual-based system.All crops were sown
after a knockdown,sprayed with a broadleaf selective
herbicide in-cropand top-dressed with nitrogen
at two different rates.In 2009, barley sown
in line with district practiceyielded 2.8 tonnes per hectare.Grain yields were similar for crops
sown over perennial grasses.In subsequent years,pasture cropping did not result in a
yield penalty relative to the control.The only significant yield penalty
observed over three seasonswas in 2009, in treatments
where 80 units of nitrogenwas applied to the barley crop.In 2012, the lupin crop
was reasonablebut there were some surprises.One of the things that we did notice was that
the perennial grasses differed in their tolerance to herbicides. Here you’ll notice that panic
has come back after Verdict. Contrast that with Rhodes grass, which was impacted
quite severely by the herbicide. Many of the plants
were actually killed, but we’re hoping that
they’ll come back through runners. The value of this trial is in helping
us parameterise a computer model that will allow us to look at how this farming system
will operate on different soils, in different regions,
in different seasons. Pasture cropping can be integrated
into farming systems from two perspectives –
either as a grazing system, in providing feed for stock
out of season, or it could be used as
a cropping system where grain could be harvested
from the pasture-cropped paddock in a favourable year. To explore how widely
this technology could be adopted, we’ll be using the trial to
parameterise simulation models and then use
those simulation models to help us predict
where the pastures can grow, where the crops can grow and determine what seasons that
we can get both crops and pastures growing together.Results from the Moora focus sitehave confirmed that pasture
cropping can be viable in WA,but success is dependent
on winter dormancyor suppression
in the perennial pasture,effective weed control
and adequate fertility and moisture.The experiences
of innovative growersare highlighted in the third video
of this series on pasture croppingto show how growers
are bringing all the pieces together.
