Assessing the cost of crop variability

Status: Completed

A one year MAF Sustainable Farming Fund project supported by the Horticulture NZ Vegetable Research and Innovation Board. The project developed quick methods to determine the cost of crop loss. We noted total loss areas caused by surface ponding from irrigation or poor drainage. How much was it costing? Was it worth putting some effort into mitigation?

We built a protoype calculator and tested it out on a couple of onion paddocks. We found it easy to determine areas when there were clear boundaries such as defined ponding areas. It was a bit trickier when the zones had “blurred” edges; patches of erratic plant numbers where wind had damaged developing seedlings. We made estimates we could live with.

Yield measurement was also straight forward where yield suppression was similar throughout, but a little less clear in patchy places. An amended milestone target has enabled us to create a stand alone application to use as the variability calculator. Enter “YieldEst”.


YieldEst is much simpler to use than the initial spreadsheet. And it is far smarter, more flexible and not prone to spreadsheet frailties.

YieldEst calculates the cost of yield variation, based on measurements made in the field. The three pieces of information needed are the product value, the area affected, and the yields achieved. A small Guidelines booklet gives advice on determining areas and yields and YieldEst does the rest.

The Guidelines booklet can be down loaded, and is also integrated into the YieldEst Help file.

Download the YVC Setup file here> (9.0 MB file size)

Download A5 size printable Guidelines here> (2.5 MB file size)


What crops are covered?

While we designed the calculator with field crops in mind, it is entirely valid for any crop from pasture to sweetcorn, from peas to apples. It just compares the yields achieved with potential yields, and within the area allows sub-zones of lower performance to be assessed.

Crop values are determined from data you enter about crop yield and price. You can enter multiple grades if desired.



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