5.0 - Yield Mapping

CHECKLIST FOR COLLECTING ACCURATE YIELD DATA:

• Install the latest firmware on the yield monitor and update any PC software used for data processing. 

• If the data is professionally cleaned and processed, the calibration of harvesters does not need to be accurate. It is simpler to rectify yield totals post-harvest. 

• Ensure 50% (or more) of the harvesters are monitoring yield, stagger yield monitors with non-monitoring harvesters instead of monitoring a continuous block. 

• Make sure the monitor is set up correctly; refer to the user manual or dealer for queries. 

• Verify data is being recorded to the storage device soon after harvest begins, it is too late when harvest is completed. 

• Where possible, harvest with a full comb width. 

• Consider providing contractors with a memory card and/or USB stick. 

• Record the actual tonnage from each field if calibration is to be performed post-harvest. Calibrate the data and ensure that errors are removed before the data is interpolated. 

• Make a copy and a backup of raw yield data on an external hard drive or cloud server for safekeeping. 

• Record and collect yield data every season even during poor seasons.

Monitoring yield is a simple and economical method used to measure the impact of environmental, agronomic, and management factors on yield. It is often considered a logical starting point for developing information about inherent field variability.

Most new harvesting machines come equipped with a yield monitor. Older machines can be retrofitted with a system. Using yield maps to quantify spatial and temporal variability may have an immediate impact on management decisions or the usefulness of this information may increase over time as it is interpreted with other spatial data.

Yield data can be used for:

• Estimating nutrient removal from a field.

• Generating variable rate application maps for subsequent crops.

• Analysis with soil data layers such as EM to determine changes in production potential within a field.

• Developing accurate gross margin information.

• Post-harvest analysis or insurance claims.

• Multi-season analysis and the generation of permanent management zones.

• Analysis of on-farm trials.

• Analysis of terrain data layers for economic assessment of land forming.

Accurate yield data is essential if it is to be used as the basis for making decisions. Most people recognise that the correct installation and calibration of a yield monitor is required, but it is also necessary to clean and process the data generated by a yield monitor.

The data taken directly from a harvester is often highly variable and will contain errors. It is paramount that yield data is ‘cleaned’ using the appropriate filters. Erroneous data points must be removed or corrected before the data is interpolated.

ERRORS IN YIELD DATA WHICH CAN BE RECTIFIED POST-HARVEST ARE:

• Inaccurate yield totals or data spikes.

• Depending on the amount and location of missing yield data, interpolation techniques may be used to overcome the loss of data.

• Time delays (e.g. mass flow), GPS and positioning offsets in yield data collection.

• Overlaps in data or gaps due to incorrect or differing cutting widths.

• Correcting and eliminating overlaps.

• Incorrect field labelling on the yield console or multiple files for a single field.

• Compatibility and accuracy issues when merging data from multiple and/or different branded machines.

To the right is a list of cleaning/editing and erroneous data removal tools from PCT Agcloud. For a more detailed description of each please consult PCT.

Most commercial mapping programs try to smooth out errors in yield data but accurate removal is considerably better. Growers may choose to do this themselves or may consult a professional data service that can offer experience and expertise in filtering the data to produce an accurate data set suitable for mapping and further analysis.

After passing through the filtering and editing phase of data import, an automated processed yield map is the result.

The raw vs. clean data is shown here:

The final interpolated yield map ready for use.