Transcript of the applying climate change modelling for irrigated horticulture in the Victorian Mallee webinar

Heather Field:

Our webinar today is on applying climate change modelling for irrigated horticulture in the Victorian Mallee. In this webinar, the project team will summarise the findings from a recent project to assess the likely impacts of future climates on dominant irrigated crops in the Mallee, we will hear how the results from this work have provided input into the development of adaptive management strategies. I will now hand over to Graeme Anderson for a short introduction before we hear from our presenters today.

Graeme Anderson:

Thank you Heather, that's terrific. And thanks for organising, getting everyone together. So just want to open up, with the webinar series, I'm looking forward to today and it's really been great showcasing, just clever people who are looking at, how do we create opportunities for our industries and regions to have discussions about climate change? Talk about adaptation and what are some of the things that we might be needing to do differently in future? So one of the key things about adaptation is that it is a participation sport, and there's lots of different levels that can be done at, and also lots of different scales. But the important thing is that always requires a lot of collaboration and work with different partners. So there's no better example of that than what's been happening, up in the Mallee region with this particular project.

Graeme Anderson:

So it's great to... And really appreciate the panelists all making time to come together today, just to share some of the work they've been doing. And at the end, we'll have a bit of a panel discussion just to try and, take some lessons, on what things works when we're trying to get people discussing adaptation at a regional and industry level. So, thanks Heather, back to you.

Heather Field:

Great. Thanks Graeme. So we're going to start with Don Arnold is from the Mallee CMA, and Don's going to give us a bit of context to the project, and linking back to the land and water management plan. Now Don is the manager of salinity and irrigation at the Catchment Management Authority. And Don has worked across Australia in a range of conservation and environment protection functions, and his current role has a strong agricultural plus working to maintain healthy productive irrigation communities that actively avoid or minimise environmental impacts. So over to you, Don.

Don Arnold:

Thanks, Heather. And thank you to Agriculture Victoria, for the opportunity to talk about the context behind the climate challenge in irrigated horticulture in the Victorian Mallee. I'm going to just give a bit of background as to where this project came from. The Victorian State Government requires that each irrigation region has in place a land and water management plan. These plans stem from the original salinity management plans or the 1990s today, while salinity might remains a threat in the Victorian Mallee, the issues the plan seek to address a much broader than just salinity. Land and water management plans are tasked with reflecting local community's aspirations. They're meant to reflect government policy, particularly state, but also Commonwealth policy in the place, and there also meant to take from the directions of the regional catchment strategy and apply those as well. So they have a variety of, I guess, avenues that are influencing what might be in a land and water management plan.

Don Arnold:

Over the last couple of years, we've been working with the local community and local agencies through a project steering committee to develop a new land water management plan. And this plan seeks to address range of threats as I outlined, and particularly, was looking to address issues around water deliverability down the river, water efficiency, continuing to look at salinity, but one of the other threats that was identified was climate change. And in developing the plan, climate change was identified as a key for it by the local community and the project steering committee, which guides the plan knew that while we couldn't fix climate change, we could support the irrigation community, to be better prepared. Our local horticultural industry in the Victorian Mallee around 2 per cent of the arid land in the Mallee, producers around about 60 per cent of the gross agricultural production.

Don Arnold:

So it's an important aspect of the Victorian Mallee. And one that we wanted to protect, the CMA was funded by the state sustainable irrigation program, which seeks to provide information that would support irrigation, addresses some of the key actions in the land water management plan. The CMA asked Agriculture Victoria to manage the project and assess the implications of climate change for horticulture and the Victorian Mallee. It was felt that the relationships Agriculture Victoria had their experience and skills was best placed to drive this project forward. Together we commissioned Anna Roberts and Anna will talk shortly with Natalie from Natural Decisions to deliver the project. And we also were aware that Natural Decisions had done some work in the northeast part of the state already. And we thought we'd try and capture the learnings of that and applied in the Victorian Mallee. So I'll pass now over to back to Heather then we'll pass on to Anna and Natalie to talk through what have been the findings from the work that we've done.

Heather Field:

Great. Thanks for that, Don. That's a good introduction there. Yeah, so I will be handing over now to both Natalie Mason and Anna Roberts who will give a bit of a project summary some information about the key findings and what some of the next steps might be. Now, Natalie Mason is an irrigation extension officer with Agriculture Victoria and she's based in Mildura. And she was the project manager for this project. And as Don mentioned, Anna Roberts is a director of Natural Decisions for the past 30 years and has experienced in research extension and contributing to policy reform. And her career has been on understanding the impacts of agriculture on the environment and developing farming systems, which reduce environmental impacts. So I think I'm now handing over to Natalie to start her presentation. Thanks Natalie.

Natalie Mason:

Thanks Heather. Thank you for joining us today everyone, I will be giving you an overview of the results from our project and then some of our plans for the future, and I'll be presenting with Anna. So what the aims of our project? The crux of our project was to look at what the production response of key irrigated crops in the Mallee would be to climate change. And we would do this through a process of modelling. And within this process, we will be identifying some of the knowledge gaps on the impacts of climate change. As another part of our project, we also looked at available research to see what alternative crops may be successful in the area and identify some adaptive management strategies. So what was our approach? Well, for the first component, we had our literature review, which looked at these climate adaptation strategies and the alternative crop varieties.

Natalie Mason:

Then our main part of the project involved the modelling process, and this started with our stakeholder group, which identified our crop varieties, phonology and representative locations for our modelling. We then went away and did our modelling at the point scale first and then scaled across the irrigated Mallee, which is the region that you can see in the map there, we came back with our preliminary results through our stakeholder groups and ironed out any of the assumptions that may not have been quite right in the model at the time, and then went away and redid all of the modelling and then came back and presented the final results to our stakeholder groups. So very briefly the model that we used is a generic heat unit model. So what this means is that crop development is a function of accumulated heat units or thermal time. I will just chuck over to you there, Anna, if you had anything else to add about the generic heat unit model.

Anna Roberts:

Yep. Sure, Natalie. So the generic heat unit model. So there are basically three types of modelling approaches, a really simple crop factor model, a generic hate unit and model, and then a very complex approach. So we decided on using the intermediate approach, the generic heat model approach, and it's the first time it has been used for horticulture, the reason we wanted to use it was that we were able to capture, it can capture the phonology of the crop. So you can define what date crop, flowers, harvest, et cetera, and then use that to help predict what impact that will be. That's in contrast to a much simpler crop factor approach where it can't really take into account growing season days and heat units. The other use reason we use the heat unit approach heat, the concept of heat units is pretty well understood by the horticulture industry. And so we figured we'd make best use of available local knowledge as well as be able to look at things like changing growing season days, which we couldn't do with a much simpler approach.

Natalie Mason:

So at our stakeholder meetings, we had three commodity groups coming together. We looked at citrus, vines and almonds, and each of these groups, we had them identify which crop variety they would most like to see models and have these production impacts assessed. And this was also based on where we had the best available knowledge on these crops. We also had these groups select representative locations. So a typical location that you would grow these crops that we could define the dates, the phenological stages, average yields and irrigation volumes, and match this to historic climate. We also had our producers identify what we termed a yield penalty or a crop yield reduction rule of thumb, essentially what we mean by this is these crops sensitivities to certain climate events, which would cause a defined reduction in yield.

Natalie Mason:

So as an example for Washington Naval citrus, we identified that two consecutive days over 45 degrees would result in a yield penalty of 25 per cent. And we can also match these crop yield reductions to specific phenological stages. So it's an example for almonds, we would a 5 per cent yield penalty if temperature is minus two or lower from the start to the end of flowering. So once we had this information, we went and did the modelling, and we did a point scale calibration at first. So you can see to the map on the right there, that we had four key locations and each of them was matched to a climate station and a particular variety that was grown in the area for so for dried fruit, we had Sun Muscat, table grapes, we use Crimson seedless, wine. We looked at two varieties, Shiraz and Pinot Gris, citrus Washington Navel and almonds.

Natalie Mason:

So after we had our point scale calibration, we modeled four climate scenarios baseline 2030, 2050, and 2070. Remembering that those single years actually represent a 30 year timeframe. And after we were satisfied with that modelling process, we scaled it across the irrigable Victorian Mallee. So our key results, there were yield declines in all crops. We see this happening as a result of increasing heat stress and more yield penalties occurring each year and across years, there were no frost impacts predicted in the future. And it's worth remembering that the modeled climate doesn't account for extremes well. So we're not necessarily capturing the very high temperatures or very low temperatures. These yield the clients also assume that there are no changes in the varieties that have been grown or the management practices that are currently in place.

Natalie Mason:

And we know that this wouldn't be the reality, and isn't the reality with our growers. We saw that the growing season would become shorter and there was a decrease in water use efficiency. So our point scale results, we see yield declines across all crops. This most significant decline we see is for the Sun Muscat the dried fruit and we had the lowest yield declined for Crimson seedless. Anna, would you like to make some comments on these results?

Anna Roberts:

Thanks, Natalie. So yeah, I mean these results, the combination of the predictions from industry. So I think what we can say is that certainly we were very comfortable with the calibration in most of the crops, less so in table grapes than the others, but the calibration was good. So we were able to match average industry yields and average industry water use then the yield declines solely based on both the penalties that industry suggested were applicable, like the 25 per cent yield reduction, the citrus or whatever, and the climate. So, I mean, I think given the newness of the modelling, we were really impressed that we were able to match the character building irrigation requirements really well, and the yield declines, also, and as Natalie said, these don't take account of the extremes, but the yield declines look certainly plausible if you assume, no changing management or variety.

Natalie Mason:

Yes. And another useful way to look at this is the probability of exceedance for the median yields. So how likely is it in the future that we will see a current median yield maintained, and we can see that for some crops that is quite low. So for Washington Navel, Pinot Gris, and Sun Muscat, and I'll let Anna talk a bit more on this one as well.

Anna Roberts:

So the baseline is 50 per cent of the time, but you would expect to see a particular yield. So if we're saying that 50 per cent of the time, we're going to see a particular yield, it means that say for Washington Navel by 2030, we'll only see the probability of exceedance of a median yield of 35 per cent and so on. So it's saying that, being able to maintain yields, is going to be more and more difficult if we don't have adaptation, different varieties, et cetera.

Natalie Mason:

And we can see this a lot clearer when we start looking at the frequency of yield penalties. So we can see that by 2070, although, that 30 year timeframe that's represented by the year 2070 for Shiraz, Sun Muscat and Crimson seedless, we would expect to see yield penalties. And these are all heat-related penalties occurring in every year in that 30 year time series and information that I haven't presented here, but that we do have is that within these years, we're expecting more of these penalties to occur as well. So the impact of each of these events is higher in the future.

Natalie Mason:

So we also saw a collapse in our growing season days. We see, say for example, in Washington Navel, but through to 2070, we'll have a 1.2 days per year decline in our growing season. And we're quite confident in these results because this matches quite well with historic data we have from New South Wales that suggests that flowering is compressing by 19 hours every year, since 1990. And as a result of our reduced yield and shorter growing seasons, we're also seeing a reduction in water use efficiency, over time across all commodities. So throw to Anna here to talk a bit about our spatial results.

Anna Roberts:

So as Natalie has said, we first of all, got confident with the model in terms of a point scale. So we modeled for example, almonds at Robinvale and Grapes elsewhere, Merbein or Mildura. So we got confident with the modelling results for the point scale modelling results first. And then once we were confident that the calibration was right or as good as we could get, we then applied the results over the landscape. So the results that you see, that are completely driven by the climate data. So for example, if we just look at the first one to 2030 we've got blues across the region. So we're saying a small yield change across the region, more in 2050 and more in 2070.

Anna Roberts:

So one of the things that you can see for the 2050 and the 2070 results is that the yield changes look bigger, or the yield declines look worse in the Northern part of the region, then the Southern part of the region. So the big question is, is that a real result? And the answer is, it's really the extent to which we believe the climate data, that those results are being driven by. So there are uncertainties with climate, so you wouldn't use this in the first instance to say, 'Well, I wouldn't grow stuff in the South versus the North.' You've got to be confident in the climate data. And there is still significant uncertainty with the climate data, same kind of issue, and what we can see with the growing season days.

Anna Roberts:

We can see that overall, there's certainly a shift in growing season days, which means the season is getting shorter. And as Natalie said, we're quite confident about that because the industry is already seeing that the extent to which you believe whether there are differences between north and south is again purely driven by the climate. So I think, we've made some big advances with the modelling. It's much better horticultural modelling than has been done before. And the modelling itself does pass the test, I think.

Natalie Mason:

Yeah. And I think it's also worth noting if you have seen the results from northeast CMA project, that there was a lot greater variability, but that's also due to the differences in topography. And we don't really have that landscape variability here in the Mallee. So onto our adaptation strategies.

Anna Roberts:

Can I just say, Natalie, as well, there wasn't the differences that there was in the northeast but it's also important because the landscape is much more uniform, but the more interesting thing is that in the northeast, we're only able to use a crop factor model. So we couldn't pick up things like changes in water, use efficiency or anything like that. So the overall, whilst the variability is not as great in the Mallee, the modelling approach we used for horticulture was much better in the Mallee than we were able to use in the northeast.

Natalie Mason:

So thanks Anna. That was a really great part of this project was being able to make our models more sophisticated and match our production systems quite well here. So adaptation strategies, we looked at separate into two parts. So firstly looking at alternative varieties and crop types, so to start with, it would be looking at where can we get heat tolerant varieties from? And that would be looking at the geographical spread of varieties internationally, and looking for those ones like the Italian or Spanish wine grape varieties that are less susceptible to those extreme heat events. And that might be a function of how the canopy grows and where the fruits is within the canopy. We also looked at alternative crop types like Carob, pomegranate date, Chinese date, hemp, medicinal cannabis, and they are already grown in the region, but these relatively small markets, and there's no evidence to suggest that the commodities that we've looked at would be replaced by something else in the future.

Natalie Mason:

We also looked at management strategies that could be used to minimize the effects of climate impacts. And these can include changes to site orientation, how we manage irrigation using mechanical devices like netting or cooling sprays, which can make changes to the conditions within an orchard. So the key messages that we have without adaptation, we will see significant yield declines, mostly due to heat impact, but we know that our growers are already adapting to climate change and altering their management strategies, but also expecting to see a lot shorter growing seasons. Some of the challenges and gaps that we found through this process was that we couldn't account for fruit quality impacts from climate events and more specifically some of the crop production systems like table grapes, quite complex and difficult to model.

Natalie Mason:

And particularly when we want to look at fruit quality implications, we would need to look more specifically at doing one of those more detailed phenological models to start accounting for those fruit quality implications, which may not necessarily be a yield decline, but a very significant for those industries, which rely on having the high quality fruit. We also know that the climate data doesn't account well for extremes. And that's what this graph on the right is showing the orange line is silo data, which shows you quite large variation in maximum and minimum temperature. And the blue line there is the CSIRO model data for that same time frame.

Natalie Mason:

And we also have plenty of opportunities to refine our heat unit approach with more collaboration with industry. So these results, to be used to initiate our discussions with industry groups, looking at the future impacts of climate change, we want to use these models and develop better ones that can account for fruit quality and management practices that might minimize the impacts of climate change. Say putting cooling sprays on when we reach a certain temperature, we could also look to develop horticultural models for other prominent crops like olives, which weren't included in this study. And we could look to develop some tools which would enable industry to understand future climate and interact with those key climate thresholds that they can identify and see what's coming in the future and start to look at more targeted management strategies. And that's all from me. Thanks Heather

Heather Field:

Go ahead Graeme?

Graeme Anderson:

Very good. Thank you, Heather. And thanks. Fantastic, Natalie and Anna after that overview, there's just some question that's popped up for Natalie, the question is, the model crops were under irrigation or rain fed systems. So it's pretty clear the focus here was on irrigated crops?

Natalie Mason:

Yes, that's right.

Graeme Anderson:

Great. Thank you. Okay, now and the Q and A box at the bottom, people are welcome to ask questions. So please do that, but we're also going to just have a bit of a panel discussion and I'd like to welcome a couple of other members of the panel. So we have Craig Beverly, Craig you're there from AgVic. Would you like to introduce yourself?

Craig Beverly:

Thanks Graeme. Yes, Craig Beverly, I work at Agriculture Victoria centered at Rutherglen and my role is system modelling and I help provide some modelling support for this project.

Graeme Anderson:

Certainly did. And it featured in previous webinars. So thanks Craig. And we've also looked at, welcome Jeremy Giddings, Jeremy you're there.

Jeremy Giddings:

Yes. Thanks. Yeah, Jeremy Giddings on the irrigation manager at Irymple. And I work with Natalie within the project.

Graeme Anderson:

Fantastic. Thank you. So as an overview, I like to congratulate you for the way you've worked together here for the panel members, we're pretty efficient not talking a lot of funding here. This is largely being brought together by people just working together and you've really explored this topic really well. I just wanted to a couple of questions I'd like to hear from each of you and at one point as this project developed and working with Mallee irrigators, what do you think some of the key take home messages that have come out of the work? And we might start with you Don.

Don Arnold:

I guess it was interesting to note, give us that the crops one of the focus of this particular project was also to look at, "Are we growing the right crops for what our climate might be in 2050 odd years time?" And it was interesting to note that yeah, the crops that we're growing at the moment are probably the best suited that we've got at the month. It wasn't suggesting that we moved to other crop varieties. So I found that particularly interesting. So the focus, I think going forward will be more on the adaptation side than it will be on changing crop varieties. So that was probably one of the key take home messages and how we can work with irrigators, to still mind time, water efficiency. Even though, there's probably going to be greater demand on water to be able to adapt to changing climate.

Graeme Anderson:

Thanks, Don. That's terrific. Anna, any key take homes for you.

Anna Roberts:

Well, I think the fact that I was really impressed that the model worked so well, it was really impressive that the industry participated so well and got their head around modelling. It was pretty new process for them, to have to specify industry information in a way that was sufficiently specific for a model to be able to cope with. So, that was really good. I think one of the things that interested me, previously coming from the northeast Victoria, it was interesting a lot of the attitude was that well, okay, we'll do the modelling under assumed water on limited conditions.

Anna Roberts:

And I think a really interesting next stage might be other opportunities to really tailor water at a catchment scale. And also what are the yield impacts, if you assumed more water limited conditions. So we know that we've got the capacity... The modelling has the capacity to do that, and that could be done in future too.

Graeme Anderson:

Yeah. Thanks. Thanks Anna. And I know too, I think that the degree days and growing season length has been really critical here. I know sometimes we hear about Northern hemisphere and their challenge in agriculture there is, squeezing in a growing season between two big winters but here in Australia at challenges growing in between two big summers. And so largely the climate change signal is for that summer getting bigger. So, I think explored some great stuff here. So onto Natalie, any key take homes.

Natalie Mason:

I think a key take home point is, yeah, that we're going to be seeing quite significant declines in yield and productivity. If we don't start thinking strategically about where adaptation should be focused now and looking at those alternative varieties now that will better cope with those heat extremes. And that might mean planting a few rows of a different variety and seeing how they perform in current climate. Yes. So starting to really think about what specific thresholds are going to be becoming an issue for our growers in the future and yeah. Honing in on that information.

Graeme Anderson:

Yeah. Thank you, Natalie. That's really important. And I guess that is the thing that the modelling gives us insights into potential impact, but the room is all farmers and all of us working in agriculture are hardwired to try and make sure that we don't end up with those reductions by doing something differently and learning new things over the coming years. So, great stuff. So Jeremy, you there, any key take homes for you?

Jeremy Giddings:

I think a lot of has been covered, but for me, the shortening of the season, I mean, we're seeing it already and it's been observed and for it to really match up with what has been observed gives you a lot of confidence in the process. And it really spells out that there's going to be an impact in less adaptation occurs and that's already happening. I mean, cooling, sprays, netting, all those sorts of things to reduce the temperatures pruning methods to have the fruit more shielded shaded by the canopy, varietals, and the industry is already looking at that and citrus are looking at a variety from Pakistan that can handle the heat and this sort of stuff. So I think it really gives some solid background that we can help those industries along and add weight to what we think is happening.

Graeme Anderson:

Yeah. Fantastic. Thank you, Jeremy. That's exactly right. And plenty of good leads there. Okay. And Craig, any take homes for you?

Craig Beverly:

Sorry. I'm trying to get a video up, but it's not working. Yeah, so for me personally, I was really thrilled I think, and with the level of producer engagement and the willingness to participate in this process and to consider, the merging of life experience in a model context and projecting that into the future, there was a really wonderful engagement and insight brought to both parties. But I think the take home message also is that subsequent modelling has shown that there are options, viable options in the future in terms of, as Jeremy and others have said the adaptation strategies or different management strategies, as well as perhaps some varietal or changes as well. But, there's still a bright future. Thanks Graeme.

Graeme Anderson:

Thank you, Craig. Thank you. So one thing that, the next question, I'm going to go back through the panel again, but about if there was any surprises, perhaps any things that surprised you or the way the collaboration or the project brought up, any things perhaps that you hadn't initially expected when you started the study. So be interested to hear what surprises or unexpected things that popped up for you Don?

Don Arnold:

Yes. The yield decline was probably greater than I anticipated, but I guess that's probably also we now appreciate what is going to be the effect of climate change to a greater degree than what we did perhaps a few years back. So that was one, and as I said earlier, I was expecting that we might have to change some of our crop types in the region. And it's looking like we won't have to do that, but we might have to change the varieties we grow, but not so much the crop types. So Graeme, that was where I landed at least anyway.

Graeme Anderson:

Yeah. Thanks, Don. Yeah, no, I agree. I think pretty surprising, certainly you no longer at the 2070, some of the impacts substantial and I guess it's a powerful reminder of the importance that really the whole challenge of reducing emissions in the next couple of decades is really critical. Because that has a big bearing on certainly the sort of temperatures we might be wrestling with later in the century. So the better we deal with that emissions challenged, the less we've got to deal with later on.

Don Arnold:

Yeah, we're used to pretty hot temperatures here in the Mallee, but we're probably going to see more of it, not less. So, yeah, it was interesting to see that decline.

Graeme Anderson:

Thanks, Don. We got Anna.

Anna Roberts:

Yeah. Sorry. So just to pick up on the comment about the surprise about the lack of different crop types, I mean, it's not to say that there aren't other crop types, obviously, but we were really asked to look at alternative crop types that have potential over large areas. So it's not to say there won't be other crop types, but we looked at thing we did literature scan, which thought about things like, the relative advantage of growing things in the Mallee compared with overseas. So, like other production, we also thought about the complementarity of growing, with what producers are used to, and also the unavoidable fact that in the Australian context, any crop, even if it's got a great... It's got a high potential for profit and needs to be low labor.

Anna Roberts:

So we put some filters on crop types. Some realistic filters about global demand, ease of growing, labor markets, et cetera. So when you put those filters over, there's nothing that really jumps out at a scale on industry. The question about surprise, I think given the work we've done, in the northeast and the work I've been involved with previously with Craig in past life, we know that... While, it's very likely that the climate change impacts on the water supply in the whole of the Murray-Darling basin, pretty extreme.

Anna Roberts:

So modelling suggested that in northeast Victoria we'll have a 20 to 30 per cent less water supply downstream. So that emphasis, in terms of potential reduced water availability in terms of it not being seen as such an issue in the Mallee, I was quite surprised about, I guess that's because horticulture producers who are used to operating in very competitive environments, know that they're prepared to pay high prices for water, but that surprised me.

Graeme Anderson:

Yep. Okay. Thanks Anna. Natalie, did any surprises or unexpected findings?

Natalie Mason:

Well, I think one of the surprising things that came up from an industry perspective particularly when we were talking about vines was some of the results that we got for Shiraz and Pinot Gris were not what the industry anticipated. Pinot Gris is generally accepted as a more sensitive variety than Shiraz, but our results tended to show that there were more penalties for Shiraz and a higher yield impact. So it was surprising to see how the changes with phenological stages because of the reduction in the growing season, interacted with those climate thresholds, which caused the yield reductions. I also think it was quite surprising how well our models were able to match what the industry said and what they told us and including those penalties and how they looked in that historic situation. I think that was a really, really great outcome to see how close we could get that to the industry experience.

Graeme Anderson:

Yeah. That's music to my ears, Natalie. That's fantastic. And that strong verification and there's a lot of work involved to make sure that what's coming out of models is making sense, but well done there, you did that. Jeremy, any surprises from you from...

Jeremy Giddings:

I guess the yield reductions, and we've always saying it's without adaptation and those crops wouldn't persist if there wasn't adaptation because they'd become unproductive financial, but yeah, the scale is alarming without adaptation. And I guess the spatial variation as well, we followed on from the northeast project where that spatial variation was large and that was mentioned earlier, but didn't expect too much. And if you look at the scale of spatial maps is not a lot of variation, but the fact that there is some, was a little surprising and others have mentioned purely a case of the climate data that's being received. So I guess that'll be something we looked at a little bit more closely in another stage.

Graeme Anderson:

Yeah. Great. Thank you, Jeremy, and Craig.

Craig Beverly:

I think a surprise I had was the interaction between the shorter growing season and the implications for water use efficiency. I actually expected a more pronounced impact, than what we're able to model. And I think that perhaps requires further evaluation, but it was a surprise.

Graeme Anderson:

Okay. So just clarify that one, Craig..

Craig Beverly:

Well, as I said, the traditional way, it might've been to use something quite simplistic in terms of a yield and water use such as a crop model. And that would show quite a pronounced impacts under the future, in terms of water use requirement or crop water demand, take the approach that was taken that actually takes account of the shortening of the growing season of in the water use impacts and not as significant in terms of crop water demand, because there's less growing season where there's a requirement to irrigate. So I was expecting a larger impact in terms of crop water use, into the future. But you can easily rationalize that with the construct of the model and in fact, where we came to in terms of our growing season and those interactions.

Graeme Anderson:

Yeah. Very good. All right. Yeah, no, that's right. There's been some good little learnings along the journey here. So, I guess there's probably some people thinking, I know there's a lot that are trying to work out how might they do sort of this in, in their part of the world or their industry, and just wondering what advice to others would you give for anyone who's trying to deliver a regional or an industry climate change adaptation project, or open up discussions around climate change. So, given you've been through it, then we became to hear any advice that you share with others about trying to repeat this sort of a process. So back to you, Don.

Don Arnold:

I'm probably not the best one to answer that. I'd suggest that, that might be better coming from the group that actually put the work together. My role was more a sponsor of the project than an active engager in delivering. So I might throw over to others to give a more enlightened response to them.

Graeme Anderson:

Yeah. Thanks Don. No worries. Okay. Anna, any advice?

Anna Roberts:

Yeah. I think the most important piece of advice is be very clear about what question you are asking. That sounds a bit trite, but for example, the project was inspired by the northeast CMA work, now if the question that was being asked in the northeast CMA work was, how do people get access to climate information? And so we actually developed a spatial tool to allow people to have a look at what impact climate was going to have, in terms of reduced rainfall or increased temperatures, et cetera. So we had originally thought that, that might be the question that was asked here, but the question that was asked here was quite different, and it was about, what are the impacts of climate change on crop production modelling? So that was the key question, which led to apply to different projects. Then if we had asked the question that the northeast CMA had.

Anna Roberts:

So I think once you clear about what the scope of the project is, then make sure you get the best team in terms of... Particularly if it is a question about agricultural production modelling, and you are dealing with an audience that doesn't have a lot of experience in modelling, then it's really important for everyone involved to understand what the differences between the models were, like, if we had used a crop factor model, we wouldn't have got anywhere near the good results that we got from this project.

Graeme Anderson:

Yeah, that's right. And it's a good point. It might get quite different from the northeast overall, we're looking at a whole bunch of industries, whereas here the focus is a lot tighter, so that gives you an ability to burrow in. And you're getting closer to talking about modelling that actually matches, growers actual lived experience. So, yeah, that's a great point. So thanks Anna. So Natalie, any advice to others trying to tackle this task of having adaptation discussions in Agriculture?

Natalie Mason:

Yeah. I think our key is starting with our growers, starting with the industry representatives, because this whole attempt is futile. If it's not useful to them and doesn't support what they need and what they know. So part of it is building confidence in our modelling ability, but then how can we use this information to actually benefit them? So identifying those climate thresholds and what that's going to look like in the future, and yeah, we can't do that without their engagement and the knowledge that they have, which is far better than anything we have.

Graeme Anderson:

Fantastic. Thank you, Natalie. Okay. Jeremy, any words of wisdom advice for others?

Jeremy Giddings:

Wisdom, I think have a go at it. I think every region should be having a look at this thing because the method and the process is reasonably established and there's good people out there that can do it. If you incorporate that with your local knowledge it's worth having a go at it and see where it heads list initially and go from there.

Graeme Anderson:

Yeah. That's great advice learned by doing and I think you've done a great job up there in the Mallee of throwing people together which bring different parts of the puzzle to at least have a bit of a crack and learn in the process. Craig, any advice?

Craig Beverly:

Most of it's been covered. I agree, if the mindset is to start a discussion for review and engagement, but you should be undertaking this type of working, even with the current limitations and assumptions underpinning both the client data. But where you do undertake the process, I think it was really critical that you engage and partner with both producers for discipline experts. In this case, the irrigation experts, all of that collaboration was just so rewarding and helped inform the outcome, plus the interpretation of the outcomes. And it was a real value add to the project.

Graeme Anderson:

Fantastic. Fantastic. Thanks for Craig. Now, there are a few questions rolling in. So we might just take... I've got one final question for your panel members, but we've got some questions here. I might just read them out and whoever thinks is best to answer. Give them a go. So from a Matthew Harrison, this is nice study and environment where crop models are generally developed for an optimal moderate temperature range. Could you speculate on the extent to which the yield penalties may change if extremes ie increased climate variability were better addressed in the modelling? Who'd like to tackle that one? I think Natalie, you sort of brought it up too.

Natalie Mason:

Yeah. I think Craig might be best solution to talk about the model.

Craig Beverly:

Yes, It is part of what needs further review. So to properly account for the impact of those extreme temperatures or other stress factors on plant performance. We really do have to move into more phenological models, but we do have available, but we don't have the data at yet to populate. And that would very much address the issues about fruit size and fruit quality. But there's no doubt that in order to properly account for those penalties where we to continue with these types of studies, we need to improve a model construct that we've adopted in this particular project.

Graeme Anderson:

And that is a big challenge. Because we do know that the climate change modelling data doesn't include... There's a lot more surprises in the actual weather events and seasons. We'll get them what's in the current modelling, but that's all part of it. Now, Matthew Harrison's got a question here. So Matthew. He does some great work too, have you thought about comparing the variability in results across GCM so global circulation models, often the range between them can be larger than the variation between emissions scenarios within one GCM. So is there a simple answer to that, Craig, without heading into the modelling world?

Craig Beverly:

Look, it's a very good point once again. Yes. Yes. We could we'll have applied the same model to do the six available GCMs, a broader envelope of response from which we might have a bit more confidence about the median result. So yes, it's a good advice to explore other outcomes. Thank you.

Graeme Anderson:

Yeah, that's right. And I think too, that's all part of the available resources and time and how deep you're able to dig. So thanks for that one. So Glenn Fitzgerald, in annual crops, water use efficiency tends to increase due to elevated CO2 and soil coverage from early season ground cover due to canopy vigor. Can you explain why you see water use efficiency reductions in these perennial systems? So, thanks for that question. Glenn has done a lot of great work up there with the Ag phase at Horsham. So who'd like to tackle that one? I'll just read it again. In annual crops, water use efficiency tends to increase due to elevated CO2 and soil coverage from early season ground cover due to canopy vigor? Can you explain why you see, water use efficiency reductions in these perennial systems? Who'd like to tackle that one?

Anna Roberts:

Craig to tackle that one, but after he's had to go... If you don't get a satisfactory answer, I'll have a go.

Craig Beverly:

Oh, no, thanks Glenn. No, you're quite right. So generally also increases radiation efficiencies as well as transportation efficiency and some stematal type conditions, that the issue we had here is we didn't know the degree to which set response function applies to an irrigated horticultural system. We know the Ag phase in terms of annual crop systems. And we also know from a passenger point of view, but we have confidence in terms of the irrigated horticultural system and how that response function looks, what it looks like.

Graeme Anderson:

Okay, well, there's potential whole area of work there, by the sounds Craig. So thank you for that. Michael Tribbey, Michael is asking the likelihood of winter chilling requirements being met? Did that come up in discussions in the project? Anything about the winter chilling issue?

Anna Roberts:

Yes, it did. And I think we were surprised... So we did look at that. And the crops that we looked at the winter chilling hadn't reached the threshold that we thought it might've is my recollection.

Graeme Anderson:

Very good. But anyway, Michael, just follow up if you want to dig deeper with that one. And Kay Lou, has asked question two, could you please explain how did you downscale future climate data set? Craig that might be just back to you.

Craig Beverly:

Yes, thank you. We actually didn't downscale it, it was a CSIRO approach that did the downscaling. We were used in the latest Victorian climate projections, which are at a 5K by 5K. They seemed to be recognised as the best available downscale data for Victorian applications.

Graeme Anderson:

Great, thank you very much. So thanks everyone for those questions and answers. So just on a final on the run home here, I guess just like to ask each about what activities do you think would be valuable to follow on from what you've done and discovered from this project and analysis? So what do you think activities would be valuable to follow on with over the coming few years which would be useful things to help us be better off. So start with you Don, if you've got any thoughts.

Don Arnold:

So I think it will be important to go back to the irrigators that were involved in this, and I'm checking with them again, as to what we might focus on going forward. The things that have come up that people have explained were a bit surprising, the water use efficiency issue, whether that's just a factor of the models or whether that's going to be a reality, I think will be focus water deliverability down the river and water use in the region is a primary focus and a particular focus in the land water management plan. And so anything that might influence that will continue to be something I think that we will put some attention towards.

Don Arnold:

And I guess the others have mentioned that too. There was a select number of crops that were looked at with this project and whether we look more broadly on that, could also be a focus going forward. The other things that immediately come to mind, the others might have some further views on that.

Graeme Anderson:

Yeah. Thank you very much, Don. Thanks for that. So Anna, over to you, what potential useful activities could follow on in the coming years?

Anna Roberts:

I think there's a whole range of things, but I think certainly we have to look as, it's the first time such a model has been developed and there are some really simple useful things that could be done. I know when we were discussing this with people like Michael Tribbey through the project, they're things like we assumed that the growing degree days were of equal importance through each crop stage. Now that may well not be the case. So even though, so it's a very good first champ. There are probably some quite simple things you could do to refine the model with greater industry engagement and also engagement of people who understand plant physiology to get even better results. I think that'd be really simple thing to do.

Graeme Anderson:

Yeah, great. Thank you. Thanks so much, Anna. Natalie, over to you.

Natalie Mason:

Yeah, I would agree with Anna. I think that's some really great opportunities for us to refine the models and yeah, and also start to look more at how we could account for quality implications in some way. I think it will also be important for us to look at those key climate events and they were ones that we identified in the project, which are important in terms of precipitation at certain times at yield, which have impacts on harvest and how frequently they would be occurring. And when we'd start to have those interactions, if our growing season is shortening, yeah. And extracting that information as well, which wasn't necessarily included as a yield impact and giving that information back to industry. So it can start really thinking about what our targeted actions are going to be.

Graeme Anderson:

Yeah, that's great. That's a good example of how just offer some insights of other areas that we could look at. So, well done, and Jeremy, you've got plenty of ideas, probably on the activities would be useful because you're doing good stuff up there already.

Jeremy Giddings:

I think a lot of them have been covered, a couple of other major crops, but the effect on quality. And we've learned since that there is reasonable data around effective climate on certain quality parameters. And that's what growers particularly table grape growers have been paid on citrus for export. So we need to incorporate that requirements. We need to pin that down. And it might mean we need to go back to a more simpler crop factor model to look at future ETO figures and how that affects future water requirements. But it was a good project in so many ways for what it did identify and what it showed that we're missing and depending on the time and the energy and the and the funding, so many issues we could improve on.

Graeme Anderson:

Yeah, that's right. I think there's heaps of room. I agree. I think you've been done an amazing job with a small opportunity here to try and make some sense of the issue and done a lot of great work from it. And it's interesting too, because the part of the thing often with climate stuff, part of engagement is challenging. Because people think the data can be a bit negative, but the issue is, we're saying, we're all hardwired to work out. How do we solve these issues and what are the gaps have gotten? What can we do so that we avert some of those production losses by doing things differently? So, well done. I know you're in the thick of all of that. And Craig, what activity do you think the value to follow on from the project?

Craig Beverly:

I think it's been covered, but certainly working with producers and industries to advance the phenological model so that we could better define the quality and fruit size issues may require more targeted field trials or something to that effect to populate the model and validate the model before applying it in these future scenarios.

Graeme Anderson:

Thank you. Thank you. Well, thank you so much. We're a fraction over time, so I'll wind it up, but I would like to congratulate you for the insights that you've developed in a pretty short time on this project. So thank you to all the panelists. Now there's been a question just about, is there a public report available? So if anyone is after that, there will be a report. This is not one that's finalised yet, but if you leave your details with Heather, that can be made available when the report is finalized. So you're looking at fresh observations and learnings here. So thanks to all the panelists members and Heather I'll hand back to you.

Heather Field:

Great, thanks Graeme. And thank you to our presenters today and our panelists. And it definitely was a fabulous discussion that we've had today. So really enjoyable. And we had 120 people registered for today's webinar. And we had up to 70 people online, joining live today, which is terrific. So I just want to remind everyone that there is a survey when you close out of today's webinar. So we really do appreciate if you can complete that so we can keep improving our webinar series. And on your screen, you'll see there that our next webinar will be on Tuesday, the 17th of November. And we'll be hearing from Dr. Rebecca Harris, from the University of Tasmania and Rebecca will be giving an overview of the climate information that can inform adaptation planning for climate change using the wine sector as an example.

Heather Field:

And she will be presenting the recently released Australia's wine future climate Atlas, which showcases the most up-to-date climate information at the finest resolution available in Australia. So we look forward to that. So anyone who has registered for this webinar will receive an email detailing that webinar closer to the date. So we will close out there and I thank presenters again for their time. Thank you Graeme for facilitating our discussion, and I hope you all have a good afternoon.

Page last updated: 04 May 2021