Pasture cropping – results from the Moora focus site


(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.

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