Episode 1: Mallee Farming AgVic Series | Productivity gains in Mallee sandy soils with Michael Moodie
Michael Moodie, from Frontier Farming Systems, joins Drew Radford to unpack significant results from a 3-year trial to improve sandy soil productivity. In this episode, Michael discusses the findings on specific crop yields, how deep ripping significantly improved yield by reducing the penetration resistance and what must be considered before these findings can be implemented.
INTRO - Welcome to this podcast, brought to you by Mallee Sustainable Farming and Agriculture Victoria from the MSF Research Update at Lake Cullulleraine in February 2020.
- DREW RADFORD - What if you could get significant productivity gains in sandy soils just by tilling deeper, actually a lot deeper. It's the result Micheal Moodie, research agronomists with Frontier Farming Systems has been finding over a trial that's been running for three years. He joined me in the MSF podcast studio to drill down into the results.
- MICHEAL MOODIE - What we're trying to do is fix sandy soils that we know crops aren't performing to their potential on, so really focused on sandy soils and what we've found by going in there and putting a tine into the soil, say from 30cm through to 60cm deep , more often than not, we're getting a really positive yield response on those soil types to that operation.
- DREW RADFORD - So what sort of depths have people normally been tilling at?
- MICHEAL MOODIE - In a normal sowing operation farmers are commonly working in the topsoil, so top 10cm. It's very rare under any other tillage event that they're working much deeper than that. So, what we've been able to diagnose in those sandy soils is using a device called a penetrator more often than not these soils have high penetration resistance at about that 30cm through to that 60cm depth. So, I guess going much deeper than normal is allowing us to break up that soil layer, reduce the penetration resistance and therefore allow roots to grow into that zone much better, therefore giving us the response that we're seeing.
- DREW RADFORD - That's what you mean by penetration resistance, the roots have trouble breaking down past that point?
- MICHEAL MOODIE - Yeah and look, there's lots of theories about why the penetration resistance might be there. It could be just due to compaction of machinery over a long period of time, but it could be due to other mechanisms like cementing, basically in those layers with smaller particles filtering down to those depths between the sand layers over time. So, the project that we're working on is trying to focus on, well, why is that occurring? But at the moment, we know that going in and disturbing that layer is having those positive yield responses more often than not.
- DREW RADFORD - How many sites have you been working on?
- MICHEAL MOODIE - Well, yeah, just within our business, we've probably implemented ripping treatments maybe across about six or seven sites in the last three years and I've pretty much found in the first year, a positive response in each year. As we go on through time the response becomes less and last year, we actually even found some negative responses. So, I guess the point is, is the work's only sort of three years old and we're still trying to work out, well how long are the long-term benefits. But initially in that first year, we're seeing some pretty, pretty good responses that are not only improve yield, but also improve profit.
- DREW RADFORD - You've looked at cereals and legumes. Cereals, what sort of responses are you seeing them?
- MICHEAL MOODIE - So in the first year quite often across wheat and barley, if we look at all the sites as a whole, we've got a number of about half a ton per hectare yield response in that first year. Last year it was the first year that we really looked beyond wheat and barley, so we started to look into other crops such as pulse crops. And what we found there was in something like chickpeas, it was actually the potential for a much larger response again. So, what we basically found was things like lupins were increasing yield by about 20%, but you know with a chickpea, we're able to double yield and more by ripping in front of these legume crops. Which is telling us that they're very sensitive to whatever the constraints are in these sandy soils.
- DREW RADFORD - That's a significant yield gain.
- MICHEAL MOODIE - Yeah. Now that's the yield gain, there's still more work to be required because the other thing with these crops is we've got the positive response from the ripping, but as farmers go out there and try to implement this practice there's lots of other things that they need to think from, from a logistics point of view. So, seeding into these soils, controlling soil depth, getting a fertilizer and herbicides strategies, right? There's a whole heap of work that we're sort of working on now to give people better advice for that and that's the one downside of the legume crops is they're probably more vulnerable to some of these other things and not as robust as a cereal crop is. So, while we're seeing some really positive responses at the moment, we're not really advocating for people to adjust yet, go out there and rip in front of every legume crop. But we need to work out how we can do that successfully without having any adverse consequences along the way.
- DREW RADFORD - You did say that you found a significant response in the first year, but you haven't done it long enough to see whether that's a long-term trend, but did the yield response stay similar into the next year and I assume there's also seasonal variability on top of that as well?
- MICHEAL MOODIE - So to give you an example, probably from our longest site which is a site that we established in 2017 at Ouyen, we've actually got two treatments there. One treatment is that we ripped at the start of 2017 and we haven't ripped again and then we had another treatment where we've actually gone in and ripped every season. So, where we've ripped in say 2017, we had obviously a big positive response in the first year, about 0.8 of a ton. The next year probably a bit less about 0.6 of a ton. This year we saw another benefit, but you know, it was getting down to sort of 0.2 - 0.3 of a ton. So over time that is diminishing. Where we we're ripping each year, we've seen that benefit hold true. We've basically been able to sort of get that 0.8 to 0.6 of a ton each year from the continual ripping. So yes, the ripping is only going to last so long, we're thinking in that sort of three to five year mark, but we're still got to experience a lot more sort of seasons and the seasons that we've sort of had have been pretty low rainfall seasons as well, which is making that longer term outlook a little bit harder to attribute.
- DREW RADFORD - I did notice though in your presentation, you talked about adding. Putting in additional nutrients above base fertilizer and the result wasn't what I would have expected.
- MICHEAL MOODIE - Yeah, so I guess we sort of came across ripping by accident actually. Our initial trials really looked at how could we change, how we were putting nutrients into the crop? And we thought that that would be the winning strategy, so, we were thinking, we know that when we test these sands, they're very poor fertility in the sub soils. Like they're very poor overall, but when you really get deep into the sub soil, there's very little nutrition there. So, we thought let's go along and put, instead of putting our nitrogen top of the soil, let's stick that deep down in the profile. Now, we haven't really seen much benefit of taking that approach, keeping the nutrition in the topsoil has been what's been beneficial. But along the way, you needed a mechanism to do that and by sort of doing the ripping that's what's given us the yield response. We've also been looking at other organic matter sources, so thinking that we can build up that base soil fertility by maybe taking organic sources and putting it on farm. Some of the things we've looked at include vetch hay, which you might be able to grow on your own farm and put it on the sand and incorporate that in. Composted materials and also chicken litter, which is a very popular source in particularly spots in New South Wales and South Australia, where farmers have close access to chicken sheds and stuff like that. The results have been very mixed, sometimes I've seen a result. Quite often, we haven't, again, through some dry years, but the one source that really does sort of come well above everything else has been the chicken litter. So at our trial site at Ouyen, by putting chicken litter in the soil, we've increased yield by about two and a half tons over a three year period, than what we did when we didn't do anything at all, but even that two and a half ton yield benefit over that period probably wouldn't pay for the cost of actually putting that chicken manure there. But as a project, we're very interested to try and work out what is in that particular manure and can we perhaps replicate that in another way to get that same yield benefit with less cost of getting that onto Mallee farms? Because we really haven't got a source of that product close enough for our farmers to be using on a commercial scale.
- DREW RADFORD - You touched on the point there, the cost of actually getting that in there, there's obviously a cost as well associated with going this deep. What sort of costs are you looking at because you change your equipment and also, you're going to chew threw more diesel doing it, I assume?
- MICHEAL MOODIE - Yeah. So, estimates of the cost so far, really those costs come from talking to individual farmers. We think somewhere in the order of sixty to a hundred dollars per hectare will be the cost of a ripping operation. Now, when you look at the, return on investment at a site where like Ouyen, where just even the once off rip has returned one and a half tons per hectare in grain yield over a three year period compared to doing nothing. Obviously, the benefit starts to sort of stack up, but, you know, that's something that we really need to keep these trials going for longer because we need to know what happens over a four or five, even 10 year period to really work out what's the long-term cost benefit of some of these operations. So, it's early days at the moment, but we're really confident that we're coming out with strategies for farmers that are going to lift their overall production and profitability on these Sandy soils.
- DREW RADFORD - Michael Moody, all the best for extending this trial further into the future, it'll be interesting to see the results. Thank you for joining me in the Mallee Sustainable Farming studio today.
- MICHEAL MOODIE - No worries. Thank you very much.