Stonefruit nectarine drought recovery response to deficit irrigation

Video Transcript

I am standing in an experimental orchard, a stone fruit orchard today, and we've been conducting a study on drought recovery responses to deficit irrigation. And what we're looking at is those responses of the historical deficits, whether that is there any recovery or not in the full irrigated year, this current season.

Yeah, and it's important because the information on drought recovery and productivity and fruit quality and yield is limiting on stone fruit. So, what we've been doing is fully, as I said, fully irrigating these trees this year and doing scans with a cartographer, a mobile sensing platform. And that platform's allowing us to scan the trees, look at tree size, canopies, and also focus on the individual fruit, look at fruit growth, fruit size, fruit colour and yield. So we've done scans right through stage two and stage three of the fruit growing season. These fruit will be harvested in another couple of weeks, at the end of February. It's a September Bright nectarine cultivar, and harvest time is around the end of February, start of March.

We're collecting the data across the season and using mobile platform technology and artificial intelligence and the latest sensing technologies to scan these trees, look at the responses from the historical deficit irrigation treatments.

So, I'm standing beside the Green Atlas photographer. This is our mobile platform to sense tree and fruit metrics. It's on an ATV. This one's actually an electric vehicle. But the sensors are all based at the back here. We have strobe lights, RGB high resolution cameras, LiDAR, the infrared temperature sensors, and obviously the GPS. So, all these sensors are working at high speed, multiple times per second as you scan up and down the orchard row to collect that crop and tree information.

Some of the measurements we're taking with the cartographer are looking at the fruit and looking at the canopy. So, for example, fruit size is important, fruit colour, the number of fruit on each tree, the total canopy, leaf area, and tree size. So, these metrics are being used to indicate the productivity and the response to deficit irrigation.

On top of that, we're sensing tree stress through thermal indices, so we are measuring canopy temperature with an infrared technology, sensors, and we can calculate crop water stress index, which is an index of water stress and canopy temperature, obviously. So, we're using all these metrics, production metrics, tree size metrics, fruit quality metrics and crop stress metrics to give us a performance of each individual treatment and tree, compare the historical deficit irrigation to the current season, full irrigation, in looking at that drought recovery response.

So far, the orchard scans with the cartographer has shown that in terms of water stress, the crop water stress index and the canopy temperature information, is there's no difference between treatments, historical deficit, irrigation treatment. So that means our crop water requirements being met this year, and the trees are matching crop water requirement with irrigation supply. However, we are showing reduced fruit size and potentially lower yields, which we haven't finished harvesting yet, so until we come to maturity will confirm that with the cartographer. So, the historic deficit irrigated trees at, it’s at high levels of deficit, like 20% crop water requirement, historically haven't recovered and their fruit size is lower, which is a good finding. The RDI strategy historically where we've irrigated at 40% during the stage two of fruit growth historically has shown no effects of fruit size this season. So that means that strategy works and there's no long-term carryover effects. So, we're getting some drought recovery responses and the final scan at harvest time in a couple of weeks will confirm yield and fruits, final fruit size and also final fruit colour differences if they're there.