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Episode 2: Mallee Farming AgVic Series | Daniel Bell demystifies zones, soil sampling and data sets

March 18, 2020 - 11:47 pm

Daniel Bell, Precision Ag specialist from Nutrien, joins Drew Radford to chat strategic soil testing, zoning techniques and data sets. Daniel explains how available data sets can be used to determine what sampling strategies can be used, how many zones are set and how to interpret the data to a usable format to then do a soil test.

Podcast Transcript

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 - With soil sampling it's all down to what you're trying to achieve and sometimes that's not as simple as increasing yields and reducing costs. That's the view of Daniel Bell, Precision Ag specialists with Nutrien, he joined me in the MSF studio to de-mystify zones, soil sampling and data sets.
  • DANIEL BELL - It's definitely localized on what data sets people can be using or should be using and I think it probably is the first question that we need to be answered is what data sets do they have available? You know, do they have yield, do they have NDVI or even just simply a Google earth image on Google earth of the bare soil? So, that's probably the first one and then from that you can flow on to what sampling strategy we can do from that and how many zones do we set. But yeah, from the initial point, you know, what do we have available? And then how can we get that in a usable format to then do our soil test?
  • DREW RADFORD - Okay, let's break that down a little bit further NDVI, what does that even mean?
  • DANIEL BELL - Yeah, so NDVI stands for Normalized Difference Vegetation Index and all it's really doing is it's a satellite taking a photo and then measuring the reflectance coming back and it's a good indication of biomass. So, it has multiple uses in different production systems, but that's the crux of it.
  • DREW RADFORD - As a data set then you're basically getting images from space, how well can you zero down into your paddock to get a bit of an idea of what's going on in different areas?
  • DANIEL BELL - Yeah, so the main software programs use Landsat and Sentinel, so that gets down to 10m resolution and then up to 25m. So, you can drill down further with drone imagery and whatnot, but yeah, satellite images 10m and 25m, that's how much we can get down to in paddock.
  • DREW RADFORD - What sort of money you're looking at for paying for those sorts of data sets?
  • DANIEL BELL - Yeah well, NDVI it's a bit of a freely available source these days, you know, two or three years ago you were paying a per hectare charge and you could only get one or two captures, whereas today you use certain platforms and it's free. So just knowing which ones are which, and they all have different outputs, I guess you could say, but right now you could access it for free if you've got the skills to get it.
  • DREW RADFORD - Okay and even Google Earth?
  • DANIEL BELL - Yeah, oh Google Earth doesn't have NDVI as such, but Google Earth you can download on your computer and then use the bare soil images to do things like strategic soil testing and things like that, which is obviously free, so these platforms and whatnot are becoming more readily available at a low cost.
  • DREW RADFORD - They're the data sets, so what are you looking for?
  • DANIEL BELL - Yeah, that's a good one, it's a good question. Well, what are we looking for? Well, let's go back to the project that we're doing at the moment. We're looking at delineating high and low production zones and then from those high and low production zones, we want to be doing some more site-specific testing. So, all we're doing is basically saying this is a high producing zone versus a low one.
  • DREW RADFORD - Does that only tell you a part of the story though, is that when you've got to go to the next step and start doing your zoning and your sampling?
  • DANIEL BELL - You do, exactly right, that's the next step. The interpretation bit is the bit that people might get a little bit scared of or is a barrier to implementing some PA tools or PA strategies. So having that, whether that's through your agronomists or going to things like the MSF meeting that we're at today, people can gain the knowledge on how to use those data sets to then come to an outcome and we can go from there.
  • DREW RADFORD - Daniel, in the Mallee, what sort of zoning strategies are most applicable?
  • DANIEL BELL - Yep, good question. I think up here we've got really, really clear distinct soil types. So, between our sands, mid slopes, and flats, we could utilize yield data and probably even an in season NDVI at the right capture date. To delineate those soil types and then post that we can start to think of things like site-specific sampling and then a variable rate strategy from there. So that might be variable rate phosphorus at sowing, might be variable rate nitrogen in season. But I think up here with clear distinct soil types, the very bare bones is to get yield and then make it zones off yield.
  • DREW RADFORD - It's a lot of data that's coming in to make a decision, is that an expensive process?
  • DANIEL BELL - It's getting cheaper. Resources now like Precision Ag companies and we've got our own Precision Ag team at Nutrien. You know, it is getting cheaper to do, you know, things that this project were meant to figure out is what's the economics behind soil testing. Because there's not a lot of work out there at the moment between site-specific soil sampling and what the grower actually gets back in his pocket money wise. So, I can't give you a definitive answer right now, but yeah, hopefully we can in time.
  • DREW RADFORD - The choices here all come down to what you want to achieve, I would have thought your achieve was high yield and reduced costs wasn't it?
  • DANIEL BELL - Yes. Yes, definitely, I guess what I was trying to get at is our zoning techniques, what we need to have is our outcome in the front of mind. So, if we're doing strategic soil testing off of yield then that will determine how many zones we use and what data sets we use. If we want to variable rate phosphorus at sowing time by a soil type, well then that again will then determine how many zones we use and what data sets we use to achieve that outcome. So always have your outcome in mind. Maybe we need to drill down a little bit further than what's boosting productivity or saving us costs, into what we're trying to achieve in terms of variable rating or is it just site-specific management, those sort of things.
  • DREW RADFORD - Daniel Bell, thank you for joining me in the Mallee Sustainable Farming studio today.
  • DANIEL BELL - No worries. Thank you.