Video Transcript: National wheat Free Air Carbon dioxide Enrichment (FACE) array

Dr Glenn Fitzgerald

Small rings, south of Horsham, are helping scientists better understand the potential impacts of higher carbon dioxide levels under the climate change.  Called the Free Air Carbon Dioxide Enrichment or FACE project, uses state of the art technology to simulate the impacts of changing climate and observe how this affects crops, soil and insects.

Dr Glenn Fitzgerald:  FACE stands for Free Air Carbon Dioxide Enrichment.  It’s a method we have for studying the effect of elevated carbon dioxide on crops.  What we do is establish a series of rings in which carbon dioxide is actually injected over the crop that’s grown inside of the rings.  The reason for doing this is that we anticipate that carbon dioxide levels will increase from the current levels of 382 parts per million up to 550 parts per million in the year 2050.  So we’re looking ahead about 40 years or so in terms of the response of the crop to CO2.  We have planted now…we’ve finished our third year in wheat production, so we've gone wheat, wheat, wheat, if you will, and looking at the different response of wheat crop to elevated CO2. 

Within each of these rings – the 16 metre diameter rings, in which we have lots of subplots in there, we also have a number of different factors that affect the growth of agronomic crops.  One of them is irrigation, of course, so we actually…you can imagine the ring sort of being split in half in terms of how we apply water.  One receives just rain-fed; open to what comes from the sky, and the other is rain-fed plus supplemental.  So we add a bit more, so we have two different levels of irrigation and we can understand then these two different environments, if you will, within the context of the elevated CO2.  We also have different varieties of wheat, because it’s quite well known that different varieties of plants, especially agronomic plants, respond differently to different sorts of environments.  So within that we have different varieties and on top of that, then we also have nitrogen inputs that vary. So we have a number of different factors within carbon dioxide that allow us to study these different effects on the crop. 

Another very important factor in when you’re talking about climate change, besides the water, the CO2, is temperature.  Now, temperature is actually rather difficult to get at in terms of setting up an experiment in the field.  How do you control temperature?  How do you change that?  What we've done is we've picked a method where we actually plant the crop at two different times, which is called time of sowing.  And what that does is it forces that later planting to mature at a hotter, drier time of the year. So that allows us to understand the effect of temperature at a very critical development time and again, that’s another factor.  So, we set up these experiments to look at all these different environments in which plants will be growing in the next 40 years or so under elevated CO2.  And the whole concept of climate change is the idea of all these interactions; it’s not just one thing. It’s not just CO2, it’s not just temperature and it’s not just water or rainfall – it’s all these factors. 

This particularly experiment is the only one in cropping systems currently operational in the Southern Hemisphere, so we think it’s…we’re pretty proud of that; it’s a big deal.  And it’s one of about 30 experiments and FACE experiments that have gone on over the past 20 years.  Results from the first three years of the experiment include increases in biomass, which in agriculture, translates into increases in yield and we’re seeing about a 20% increase in yield because of the elevated CO2.  Now, the caveat there is that you can see increases in yield, but you also have to have sufficient water and nitrogen still to grow the crop and considering changes in climate, if this area of Australia, for example, has decreases in rainfall then we may not see the responses to be quite that dramatic in the future, but that’s why we’ve created these different environments within the FACE ring, with lower and higher amounts of irrigation, to understand those differences.  The reasons that we see increases in biomass and yield is because carbon dioxide acts as a fertiliser to plants.  The carbon dioxide comes into the plant, it’s converted to carbon, which is what the plant uses to build its structure and its leaves and then it creates more biomass, more yield.

Now, other results that are important to the agricultural industry is that we see a decrease in the plant nitrogen content.  Now, nitrogen is a fertiliser, it’s what causes the green part of the plants to be green and that’s important…what happens is that translates into less nitrogen in the grain, which is less protein.  So that interacts directly with quality issues and the wheat industry would be quite interested in understanding that.  So, the nitrogen content, the protein content goes down and we’re seeing that very consistently.  However, what’s interesting is that the total nitrogen extracted from the soil increases and that’s because there’s more biomass.  So it’s just pulling a lot more nitrogen and that has potential impacts to future farming in terms of fertiliser requirements.  We don’t have strict answers to this point, but we’re finding these differences and these changes, which ultimately will translate into information for the farming industry. 

If we have real world data, we can actually use this data to what’s called validate crop simulation models.  Now, what that means is that we use computer models to actually look at the future and you’ve seen this, you look on TV and on the internet and you see these models that tell you what impact the future climate will have in 20 and 40 years.  The same thing can be done with crops.  So we try to use this data to make sure the crop models are right.  They can predict whatever they want into the future, but they only know if it’s correct by looking at real data.  So this provides a real solid data set for them to model the effect of future climate on the crop.  And that then allows the farming industry and policymakers to make decisions about adaptation and how we’re going to adapt to changing climate.  And CO2, from a plant perspective, is the fundamental driver for all of that.