Cotton Seed Distributors article

A video version is available at www.csd.net.au/  

Dr Mike Bange outlines recent changes to the Crop Development Tool on the Cotton CRC website. The updated tool gives growers and consultants crop performance comparisons with an model crop.

Crop Development Tool

Today I am talking to Dr Mike Bange from the Australian Cotton Research Institute. One of the many tools that are on the website that is being developed at ACRI is the crop development tool.

So Mike, could you firstly explain a little bit about what the crop development tool is?

The Crop Development Tool was a decision tool that we developed in response to a need to develop something to help with the growth of the Bollgard II crops. There was concerns about the high fruit retention and the growth of BGII crops. With its different growth habit and we basically looked to try and develop a tool in response to giving growers and consultants something to see whether their crops are performing or not and assist with making decisions.

So Mike how does the tool work?

Well Rob it is a simple tool in the sense that basically it compares measurements that are taken in the field on things like fruit counts, node counts and those sorts of things and compares with a potential growth. The potential growth that you are comparing with is based on crop development that is driven by the day degree calculator that exists on the website.

You have made some changes to the tool this season compared to previous years. Can you explain a little bit about those changes and what they will do?

It was in response to a need to have a bit of a broader package of looking at the crop growth and that with the existing tool, you were looking at fruiting nodes and you were looking at fruit counts and the other part of that was to look at the vegetative growth of the crop. So what we have got in there now is a tool that helps calculate VGR (Vegetative Growth Rate) which is the change in crop height relative to the nodes that you are producing to assist with any PIX management decisions that you might need to make. It is also just to see that you are getting that balance between your fruit load by the measurements of fruit numbers and balancing that with the actual growth of the crop, because it is very important, especially in the case of the Bollgard crop that you have got a plant big enough to support the fruit load that you are actually trying to generate.

We might go through some examples on the computer and also how we go about collecting the data. So we will move to the computer now and run through some of those examples.

No worries.

So Mike how do people get to the site where they can look at the crop development tool?

Rob, basically all of the decision tools that we have developed now are on the CRC website under the CottonLOGIC part of the website, so if you click on the CottonLOGIC part of the web site you can get to what we call CottonLOGIC tools on the web and under that you will find the crop development tool. Following that you neet to register or log in to use the crop development tool because you are actually entering data and often going back and reusing that data to generate pictures of what is going on over time.

So basically growers or consultants just enter their email address and a password and that creates the area?

Very similar to any other login process. Then you have to create a new crop, in this case I have created a crop already. You need to name your crop. You have to select a location if you want to use the silo data quick calculator you have to go and find your location and enter and you also have to enter the sowing date. Following that it is quite simple to enter any observations that you might make in the field. There are a number of options, you enter your squares per metre, bolls per metre, squaring nodes per plant, nodes above white flower and for the new part of the website for the VGR you need to enter you node count and your plant height.

I guess most people are familiar with the squares per metre and bolls per metre, although we might talk about the definitions but squaring node, what’s actually a squaring node and where do you start counting?

A squaring node is basically a node, not a vegetative branch but a main stem fruiting branch that actually has a square or scar. A squaring node is from the first fruiting branch that you produce beyond that so you count beyond it.

So at what size? I think you have actually got a definition on the computer somewhere in terms of showing people what to count?

That is right. You can go to about CDT and it will give you some definitions of what is a node. Basically here we have here, what is a squaring node.

So you get a nice picture there?

Yes if I just expand that and you can see here that a squaring node is basically where the leaf is unfurled at the square and here is an example, not the clearest pictures but the leaf hasn’t unfurled so we actually don’t define that as a squaring node.

It wouldn’t be counted yet - it would be in a few days?

Yes and that is essentially the same definition for a square in that sense so any fruiting branch that has a square with an unfurled subtending leaf is a square.

Good, maybe we can go back to the example then…. OK. So what sort of time period do people need to take these measurements to get a snapshot of what the crop is doing?

In the case of squaring nodes and squares, obviously that’s earlier in the crop so once squares start being produced that’s when you are predicting your squaring nodes and as from flowering that is when you obviously start collecting bolls. Nodes above white flower obviously is when after flowering and the node counts and plant height for VGR is from about early flowering through middle of flowering where like I said this is really about trying to match your plant size with your fruit load that you are actually measuring.

Can we have a look at an example? Maybe that example or just an example of what you have collected and what the graph actually means?

OK we have entered some data that has been collected from the field, you just hit the analyse button. There are no real calculations or anything going on we are simply just taking the data that exists there. Its given you a select a weather station in sowing time is actually calculating the day degrees and here is an example of the output that the crop development tool is producing. So like the old tool you get the fruit development, here we can see squares being produced.

And those base lines?

That is the potential growth. That is what you are comparing it with. So here we are seeing relatively that we are producing squares that are potential rate, it is probably tracking that line for probably more variability, tracking that line and we are pretty well on target in terms of producing the amount of squares.

So nothing to be concerned about there?

No nothing to be concerned about there. You would be pretty happy with that. If we look at the next graph as you see we are not actually producing any bolls yet we are just in the square period. At this stage we have got a VGR of 6.2 and this is what we call an upper boundary and a lower boundary. A bit of an indication of maybe where you are. If you are in a warmer climate you might want to monitor and keep an eye on VGR a little more closely than say in a cooler climate in terms of lower boundary but we are sort of under that line so there are not too many alarm bells ringing there in terms of VGR.

So that is telling you that Vegetative Growth is pretty well matched to reproductive growth in that case?

No there is nothing to worry about there. In terms of squaring nodes, in terms of VGR you want to really sort of sit in this boundary and squaring nodes you are tracking that pretty well so there is no major stress pulling that up so you are tracking that pretty well.

Say in the case of squaring nodes, if you were below the lines what would that mean and what potentially would you consider to count it at.

One of the new features to make the interpretation of these things a little easier we have actually now got some simple interpretations of what is going on. You click on the bottom of the thing here, it brings up a PDF document which you can print out and here is an example of where if you are tracking below, that’s the numbers we go down here and look in the squaring node development graph scenarios. If tracking below the line the causes for that are late squaring something that has delayed first squaring or you have got some cronic plant stress due to insufficient water or nutrition or tipping our and it puts some considerations that you might have to think about. In this case you might have to look at things that avoid premature cuttout, you might need to monitor your watering and nutrition a little bit closely. So there is something there now to help growers and consultants try to interpret what is going on in terms of the crop development tool. The other feature that I probably need to point out is with the VGR, if you click on your current VGR point it takes you away to a graph where you can actually see where you are sitting in terms of your VGR, look at potential yield response if you were to apply PIX at that point in time and it also relates to what sort of level of PIX you might want to apply. Certainly there is some important considerations that you need to follow up on if your considering growing PIX. The easiest thing to consider is basically is if you think that the PIX line is starting to suggest that you might need to apply PIX you need to go back and look at things like how your number for squares at tracking or number your fruit tracking or you might need to look at fruit retention. Obviously if you have got high fruit retention lots of squares you probably may not necessarily need to apply PIX. So it is really about looking at the combination of measurements you take rather than looking too much at one individually and that is the strength of this tool.

Thanks very much for that Mike.