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Pastures In Crop Sequencing for the high rainfall zone


The project has evolved over time. When we
first started doing it, we needed a legume or a break crop in our farming systems down
here. This was a perfect opportunity to put some pasture into our cropping rotation. We inherited a cropping regime from north
of the divide. Our circumstances down here are very different. We’ve got to make a
new model for the high rainfall zone. In this environment we obviously have got
ryegrass issues that pop up here that don’t tend to pop up in our drier regions. Due to
the high livestock population we’ve had here for a long time, and in particular the
use of ryegrass in pastures, when we have gone cropping we’ve gone in with the high
ryegrass seed bank for a start, and what happened there is that we’ve actually developed herbicide
resistance quicker than nearly anywhere else in Australia. It’s time now to start looking
at other options, that don’t come out of a drum. The four main themes to the project, combatting
weeds, second theme was to try and get some nitrogen that we didn’t supply out of a
bag into our cropping systems, and the other two themes were: try to utilise rainfall that
falls out of season, with climate change and climate variability happening, we’re seeing
more and more often unusual rain events, and so we want to be able to find a way of capturing
the benefits of those rainfall events. The fourth theme revolved around building soil
carbon, and try to improve the soil biology and carbon levels in our soils. I think a couple of key points that have come
out clearly is companion species to grow with that ryegrass to improve the quality of the
livestock feeds whether it be a clover, whether it be a hay oat to try and grow some more
bulk, and preparing the quality there and the importance of crop competition and how
it really can affect ryegrass population and we saw a lot less seeds set.
Some of the results now we’ve got out of this trial, we’re actually starting to see
some economics and some figures of what we’re losing or what we’re gaining. We’ve had up to 90-95% reduction in seed
bank over two years, which is really exciting. One of the key finding was; weeds were surviving
our pre-emergents and post-emergent chemical sprays, and our canopy wasn’t closing quick
enough. And so we were getting germinations of ryegrass and radish that were going through,
and they were the culprits. They were providing the seed bank for the following year. This
project has worked on capturing those weeds, and not letting them set seed. One of the drivers of this project in this
high rainfall zone is there’s a lot of mixed farms, and traditionally a lot of livestock.
So we’re set up really well to utilise some of these fodders. The cropping system and
the livestock system need to complement each other, and work to the strength of both systems. The initial cost may be a bit greater than
letting it just run and do nothing, but the gain from extra livestock production, nitrogen,
weed competition, and hence the ryegrass. Probably just now, the importance of getting
that out for growers to fully understand, and then getting to use more extensively out
in the paddock. This project has been a great catalyst for
changing our way of thinking, one of the constraints to crop production in the high rainfall zone
in Western Victoria is subsoil constraints. Through this project, we’ve actually thought
that we can use some of the pastures that we’ve grown. We’re thinking that we can
inject that directly in the hostile subsoil, and have the same effect and help ameliorate,
make it a more user friendly environment for plants to grow and flourish. Southern Farming Systems and the GRDC have
worked together for a long time, really well. This project’s also allowed us to work with
Melbourne University, the engineering department of Melbourne University, to develop a machine
to take pasture and put it underground. Once we’re confident that we’re on the right
track, we can then involve the farmers and get them to do broader paddock scale trials.
And that’s really important for us, because we’re trying to develop a new farming system.

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