Crop load estimates are done after fruit has set. This allows for decisions on the level of management required to ensure appropriate fruit size at harvest, as the number of fruit on the tree relates to the size of fruit.
Benefits of crop estimates
Crop load will impact on decisions about orchard management and value chain activities. It is recommended that both early and late estimates are done each season.
The early estimate will help to determine whether practices such as hand thinning are necessary, while the later one provides an estimated yield for the season.
Yield information is important for discussing supply capacity with buyers as well as organising orchard management and packing shed logistics at the beginning of the season.
This includes planning the budget, pickers, packing shed and basically all the logistics around managing the crop.
Since fruit size is the single most important factor in determining market returns, estimating your crop load means you can decide on management practices that will give the best fruit size.
A crop load estimate is also important for estimating supply from WA trees and therefore securing a place in fresh produce stores around the state.
When to forecast
The early estimate should be done at the end of natural fruit drop in November/December when fruitlets are about 10 to 15mm in diameter (depends on variety). The exact time should be determined by monitoring the finish of fruit drop. This will provide time to carry out hand thinning if required.
The later estimate can be done from January to March when time permits, but should be sufficiently prior to harvest to help planning.
Many growers have been doing some sort of forecast for many years with the technique used depending on time and experience. Some methods used include:
- Experienced eye. Experienced growers get an idea of crop load from the time they’ve spent in the blocks and considering last season’s yield can estimate the new season’s load. This may or may not be written down.
- One tree estimate. Growers do a fruit count on one representative tree from a block and then multiply the count by the total number of trees in the block. The estimate may or may not be written down.
- Counting frames. This involves using a counting frame to determine the volume of fruit in a given area. This data can then be transferred to a spreadsheet, which along with other information such as tree density and size, will estimate fruit yield.
Whichever method you choose, all are based on:
Crop load estimate = fruit density count x number of trees
The more counts you do, the more accurate the result. Some consideration of the history of the block and season can also be included.