Soil moisture monitoring

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Thank you.

Hi, I'm Peter Beal with the Local Land Services. I'm a Senior Land Service Officer based at Taree. Just wanted to give an overview of the Farming Forecaster Network that we're building here in Taree and right across the Hunter region, which is using weather stations like this, plus soil probes, to give us a lot more regionally based information.

It's also cloud‑based, so it's very easy to access whether you're here in Taree, whether you're in Sydney on a visit, or even in Western Australia if you’re making a visit there. It's quite a new innovation, but there are these networks right across the country, and I just want to go through some of the benefits of having a regionally based network.

So in our weather station here we've got standard things: we've got a rain gauge, we've got wind and wind direction, and in this little box here — it's like a Stevenson screen — it's the temperature, daily temperature. And those things are all really useful just in general terms. But we've also got soil probes, which we'll mention in a minute.

So, rain gauges — having a regionally based rain gauge means you can see whether all the rainfall from an event was right on the coast, whether it was inland, how much, and you can compare what you received to what is at these different sites.

Today we're at Gary Sopers, which is located between Taree and Gloucester. We've got networks — two probes out at Gloucester, we've got two probes closer into Taree, and ideally we'd have a number of these probes spread out across the region so you can get a good picture of where the rain fell, how much, to give you an idea of how significant that can be.

In the middle of a flood, we had some advanced rainfall events in 2022 that fell mostly on the coast — like 120 mils — but very little fell inland. And it's very easy to look up and see what rainfall fell at these different sites and make a conclusion. Whereas you go back to 2021 — we had three to four hundred mils fall right across the catchment, and that is really significant in terms of telling us, you know, you've got a flood coming.

So that's just one of the things that — obviously rainfall tells us. We’ll come back to that in a minute.

The other is temperature. We've had a few events in the last couple of years where temperatures have just dropped to well below average. We've hit the very lowest in June–July last year, and again just before Christmas this year, and it's really useful to know: Why isn't the pasture growing as fast as it normally does?

And when you can actually look at the temperatures, compare them to the BOM figures, compare them to long‑term historical averages — and in particular, Climate’s a great app to look at for that — it gives you some sense of, “Okay, this is why things are happening,” and we can look back and say what's going on.

So temperature is really useful. We've got air temperature here, but we've also got probes, and probably the biggest benefit is — we'll go over and I’ll show you that although the weather station’s located here, we have a soil probe which is located over here, away from the weather station.

And it’s situated roughly about here in the grass, and it's measuring what rainfall has come in, but it's also measuring what moisture is coming out through the evaporation — evapotranspiration — of the grass. And so that gives us a very real‑time measure of: “Okay, this area here has had good rain in the last couple of weeks, but how quickly is this pasture using that moisture?”

Okay, so we're looking here at this pasture here and, quite obviously, we’re in the middle of summer — I think it's the 5th of February — we've had some good rain, paspalum’s growing, there's kikuyu here that's growing, and the question is: How much more is it going to grow?

Well, when we do get summer rains, it's often large falls over a wide area of the farm. How are you going to make the most of that rainfall?

So if it's, say, 50 millimetres of rain, it can green up a pasture like this, but it may be still dry underneath. Or 50 millimetres of rain might fall on a soil profile that's already half full, and it's filled it right up to the top. They're two quite different situations.

If you've only got 50 mil, or maybe you've got 75 to 100 in reserve — and those sort of decisions are quite helpful. Do I cut silage? Is there enough moisture not just in this paddock but over the whole farm to feed the cows and to cut silage?

And if I'm going to cut silage, is there enough moisture to fertilize and make the most of that rain — that moisture — which is probably going to be around for the next 14 to 20 days? On the decision to apply nitrogen, it really is important to see the benefit of the response.

In 2017, we came out of a very dry period with very little fertilizer applied to some of our plots, and by applying only 60 kilos of nitrogen, we achieved, in two to three weeks, 2,500 kilograms of dry matter growth. Where there was no fertilizer applied, the pasture was short — you would not have cut silage in that three weeks — and there was 1,100 very short pasture.

So applying fertilizer, particularly to low‑nitrogen paddocks, can make a huge difference to the quality, the quantity, and the whole viability of cutting silage. And if you are in that position and you fertilize, you're probably quite likely to get a growth of two to three ton per hectare of dry matter — which is great silage, produced in three weeks — and the quality is really good.

But if you don't fertilize and it struggles and barely produces under a thousand kilos of dry matter, you've missed an opportunity to utilize that moisture really well.

And having some understanding of just how much moisture is here now, or was here a week ago, really helps make some of those decisions: Should I fertilize? Should I not? Should I cut silage? Should I lock it up?

And also within that you're looking at the long‑term weather records — long‑term predictions, the short‑term seven‑day predictions — is there more rain coming? All the normal things that we look at. But by adding in what's happening in the deep soil profile is really useful.

Now these sites have been selected — they're all on dairy farms around Taree. They're all on soils like this that are well over a metre deep, and so they're probably the best soils in the region. And they're the ones we've selected ideally because they're the sorts of soils where you're going to be making these quite important decisions about: Do I fertilize? Do I not fertilize? Do I cut silage? Do I have enough moisture to sow? Is this decision coming up?

And what sort of rainfall am I going to need to achieve the goals that I'm up for?

But the idea is to provide regionally wide information on not just rainfall, but what's happening in the soil — to have it available to you day in, day out, wherever you are, through the cloud‑based recording — and just for you to get familiar with the graphs and the things that are available. So when you come to make a decision on fertilizer or silage or sowing, it's just one more added bit of information that can really help.

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