So variable rate technology basically encompasses
pretty much everything from what’s called P replacement, where we’re just changing fertiliser
to match last year’s yield, to changing our chemicals, whether that’s pre-emergent or
post-emergent. Nearly any operation in broadacre ag can be varied to some extent and why farmers
are using it is both to increase profits, but also to reduce risks. Because we all know
we’ve got variable landscapes, we all can see a yield map when we first get one and
there’s variation in it, and it’s just a case of managing that variation, whether it’s can
we even uplift the poor performing areas or can we reduce our risk on the poor performing
areas and hence lift our yields on the good areas? But every case is different, every
case is unique, that’s why we use variable rate because every soil type’s unique.
So getting into variable rate, probably the first step is getting hold of a yield monitor,
having a header with a yield monitor. It’s generally everyone’s first exposure to it
because it shows how much variation they’ve got on their own farm with their system. Going
down to the next step, it depends on where they’re up to in their machinery replacement
schedule, but most new gear is already fitted with variable rate ability, so whether that’s
a spreader or air seeder box or a sprayer. Retro-fitting’s available, but most of my
clients I advise that they just worry about it as they progress through their natural
machinery replacement cycle, just to make sure the gear’s variable rate compatible.
Probably the easiest thing is to just use your own historic knowledge. Nearly every
farmer’s got a pretty good understanding of their land they’ve driven over it that many
times. You can just start mapping out and I like to call it the “low-hanging fruit”.
So let’s map out our stone heaps, let’s map out our sand hills, let’s map out the easy
stuff that we know right, that shallow stony ground doesn’t perform, we’re going to save
some inputs on that. This big sand hill, we know it might need some increased seeding
rates or some increased phosphorous or increased nitrogen, we know what we can do there. So
go the low-hanging fruit first and that’s very simple stuff and none of those things
change from year to year. Beyond that, if it’s new land or you haven’t
got a very good handle on it, there’s such tools as NDVI mapping from satellites or aerial
drones, or your cab-mounted sensors. Then there are soil sensors such as EM mapping,
which I’m doing today. Naturally I find EM probably the most effective because it maps
the soil and the soil is something that’s not changing. You’re going to be farming that
soil for the next 30 years, so if you can nail down your soil types first you’ve then
got a very good business to build your variable rate plans on.
The most powerful part of precision ag to me is on-farm trials because we’ve all got
unique systems, we’re all at different stages in that system. So a lot of my clients are
long term no-tillers and we’re noticing a big lift in natural fertility in the soil,
and this is reducing our benefits from high rates of fertiliser so we’re getting less
of a response to nitrogen. But without on-farm trials we wouldn’t be able to analyse that
and notice that, and that leads to savings the next year. So yeah, I’d encourage every
farmer, even if they’ve only got a yield monitor, just to either have some missed strips or
some up and back strips. Just do trials on your farm because the only way to learn about
the variation is to do trials.