Episode 3: Target 50 Series | Re-establishing eroded soils with John Leys
June 23, 2020 - 1:10 pm
Welcome to the ‘Target 50 – decision making to keep ground cover in the system’ series with our focus today on managing eroded soils. This series is all about ground cover and talking through the practicalities of farming to keep the minimum recommended levels of 50% ground cover in the system. Keeping our farming systems protected from wind erosion and our soils healthy and sustainable is what we are aiming for!
Our guest in this episode has been involved with Mallee Sustainable Farming right back in the early days! He was one of our key researchers working on erosion prevention and helped guide farmers in ground cover management when shifting to no-till seeding systems.
Department of Planning, Industry and Environment NSW researcher, Dr John Leys joins us today to talk about re-establishing cover on eroded soils and some of the important rules of thumb we should consider in our more modern farming systems to prevent erosion issues into the future.
Ground Cover App mentioned in the episode:
“RaPP Map” https://map.geo-rapp.org/#australia
Video links on how to use the RaPP Map:
Report on ground cover:
We thank our Target 50 project partners, Agriculture Victoria for your support.
TEGAN BUCKLEY: - Hello, welcome back to the MSF Farm Talk podcast. We're talking all about eroded soils today and how to manage them in our Target 50 decision-making to keep ground cover in the system podcast series. This series is all about ground cover and we're talking through the practicalities of farming to keep the minimum recommended levels of 50% ground cover in the system. Keeping our farming systems protected from wind erosion and our soils healthy and sustainable is what we're aiming for. Our guest in this episode has been involved with Mallee Sustainable Farming right back in the early days he was one of our key researchers working on an erosion prevention and he helped guide farmers in ground cover management when shifting to no till seeding systems. Department of Planning, Industry and Environment, New South Wales Researcher, Dr. John Leys joins us in this episode to talk about reestablishing cover on eroded soils and some of his most important rules of thumb that we should consider in our more modern farming systems to prevent erosion issues in the future. Thanks John, for joining us today on the MSF Farm Talk podcast, you were involved with MSF right at the beginning, so can you tell us what you were working on in the early days and maybe how this has changed to what you see now?
JOHN LEYS: - Pretty much in the early days, the work was split into two parts, there were intensive field trials and they were undertaken in the three states of South Australia, Victoria, New South Wales. And there's a second part to that as well, what we call focus paddocks and they were about 50 paddocks across the entire three states, which were visited about every month to every two months to see what changes are taking place at the paddock scale. What we concentrated on was what were the land management actions being undertaken with their spraying, plowing or growing a crop and then compare that to the outcomes of how much ground cover there was and how much soil erosion there was. So in the early days we were just trying to find out what were the differences in the management practices in delivering ground cover levels and how much erosion was occurring on the paddocks. So, as a result of that we used to hold quite a few field days and they were held in each of the states for the local groups and those ones we talked about the focus paddocks and see how they were going. The work also involved looked at deep drainage, we also did salinity work in those early days, so we're also at some of the sites there were 5 meter piezo tubes which we could measure soil moisture and we're looking at how the different rotations impacted also on the deep drainage and salinity.
TEGAN BUCKLEY: - Yeah, definitely some fantastic work has been happening past and present, so moving on to my next question, as you're well aware across the MSF region we've experienced two decile 1 rainfall seasons in 2018 and 2019 and this has brought our growers many challenges. We've seen a lot of awful drift events and it's difficult to think that we've come so far in our farming systems, but yet we can still end up in a situation of widespread erosion. So, John, I'm going to throw a few questions at you right now and I'd love to hear your thoughts, firstly, why do you think that we're still seeing issues like this and you know, maybe do we need to fine tune some of our farming practices? Because I guess once we get that widespread erosion, it can be really difficult to reestablish and rehabilitate our country, what happens to the soil and how long does it take to recover?
JOHN LEYS: - Yes, so as you said, things aren't great at the moment, it's been a function that we've had very very low rainfall decile 1 rainfall for the last three years. What that means is basically the crop growth, the pasture growth just isn't there. If you want to maintain ground cover you need to grow something so there is then residual material left behind, some of which has harvested, some which is grazed and some which just oxidizes and goes back into the soil. So I think what we're seeing, and I agree with you, I've been a soil conservationist now for 30 years and I was surprised to see how much erosion has taken place. And it's got me to thinking about, well, what is causing it? We know the land management is getting better, we've been measuring land practice change in the New South Wales side for the last 20 years and we've had a massive change in the amount of tillage that's undertaken. We used to have 80% of our paddocks being tilled, we're down to about 10% now. So we know that we're getting the land management practice change, but we're still getting erosion. So why is that so? And I think it is back to that comment about you need to grow something to maintain your cover. In pasture systems which are annuals and in cropping system which grow annual plants, if you don't get the recovery growth then the cover just keeps slowly declining. So with one of our tools, the RaPP Map ground cover tool, which I can give you the web address for later, I just looked at the Werrimull farming area for the last 20 years and we can see that most winters we have at least 80% to 100% of the area protected from wind erosion. And then by summer it drops down, yeah, it can be as low as 10%, which it has been in the last summer and the previous one, but normally it's the protection level is much higher, I just think it is because we're not growing anything, we can't continually maintain cover. So we're doing all the right things, the management practices are good, but the climate has been so severe that we just aren't able to maintain cover in the annual cropping and pasture systems. The evidence that we know this is around the annualization of the pastures and things, you just need to look to the Rangelands, which have perennial plants like blue bush or trees, and they are not suffering this problem. So the management is good. It's the best we can do. But the climate extremes are such that, we can't maintain ground cover, especially when you have three years in a row, when you don't get significant growth.
TEGAN BUCKLEY: - Yeah, thank you, so you may or may not be able to give us a direct answer for this one, but looking long term, what can we do to be more prepared for dry seasons that are likely to happen again in the future?
JOHN LEYS: - Yeah, that's a difficult question to answer for two reasons. The first one is we know the management getting better, but we're still not being able to control the erosion and if the climate becomes worse, which is what some of the predictions are, then, it's going to be harder and harder to maintain ground cover. So I think the best thing we can do is think about those practices, which at least mitigate the erosion. So they are the conservation farming systems which reduce the bare ground and we've also noticed it in the last two years, most of the erosion has been on either paddocks, which have had a failed crop and there's not much you can do about that, once the crop has failed, you just got to wait for the next rain cause your cover levels are low. There have been quite a significant number of paddocks, which probably had too many stock in them for too long and I guess their cover has gone low earlier than it would have, and they've become problematic. But once again, that's also a problem because people need to derive an income and it's very difficult if there's something in the paddock, not to put your sheep in, cause you know the cost of replacing the herd is going to be so expensive. So the preparedness, I think is still about monitoring, looking at the crops, trying to maximize the cover and being aware that once paddocks are getting down towards 50% ground cover we need to be really, really careful about what we do in those paddocks.
TEGAN BUCKLEY: - Yeah, definitely, that's great advice. So I don't know if you've heard the old saying there is an app for everything, apparently you mentioned before that there is an app to check out ground cover. Can you talk us through this resource a little bit more?
JOHN LEYS: - Sure, I can. Basically, there's been a project run by the agriculture department at a federal level and CSIRO and the New South Wales Department of Planning, Industry and Environment. So over the last few years, we've been trying to make the satellite information which is available to researchers, available to anyone, so they can see ground cover levels on their phone or on their computer called the GEOGLAM RaPP map, now RaPP stands for Rangeland and Pasture Productivity. What it has is every eight days and every month, composite for the ground cover of Australia, now what the ground covers in this is the satellite sees anything which is a photosynthetically active or non-active. So think of a green plant or a dead plant, it sees that and maps it 500m pixels all across Australia. So there is an eight day time series and I'm just looking at the one at the moment for the Millewa area and I can see that the ground cover level with more than 50% ground cover on the 8th of May was 51%. So 51% of the area was protected from wind erosion on the 8th of May. If I go back in the app, I can see that back on the 25th of August 2017 it was 99% protected. So what this app does is show you for every 500 meter pixels, the ground cover level and you can go backwards in time by clicking on the app to look at different months or you can ask the app to give you a time series. You can do that for either one pixel or a group of a pixel or you can draw a polygon and we also have some caned reports, so reports will tell you what percentage of the area under grazing, what the cover levels are.
TEGAN BUCKLEY: - Yeah, what a handy tool for us to have in our back pocket, thank you John, so much sharing. I'll be sure to put the links to this app and any other handy resources relevant to our chat today in the episode description. So for all our listeners out there, you can just tap on that link and it should take you straight to some more resources in this episode. But before we wrap up, what are your key takeaways John in terms of managing eroded soils and improving ground cover?
JOHN LEYS: - One of the things that makes us hopeful for the future is that even though in extreme times, if you look around the landscape, there are still places where there is adequate ground cover. This indicates that there are management systems that do work even during extreme periods of dry. So what this means is even though there is extremely difficult conditions during dry times, we'll still see paddocks which retained adequate ground cover. So finding out why those paddocks still have ground cover and what the sequence of the farming events was to achieve it, is another way we might be able to look into the future with and promote those types of farming systems.
TEGAN BUCKLEY: - Some excellent key takeaways there, thank you so much John.
JOHN LEYS: - No worries and thank you very much for the invite and I hope that these winter rains come, and we see a massive recovery in the amount of ground cover and the cropping activity in the Mallee Sustainable Farming area.
TEGAN BUCKLEY: - Don't forget to share this episode with a mate if you took some value away from it and be sure to subscribe, rate and review our podcast. Thanks for tuning in and we'll catch you in the next episode.