New guidelines and worksheets for calibrating farm effluent irrigators have been posted on the Page Bloomer site.
Additions to the IRRIG8Quick series, two options are offered for effluent systems. Both are for travelling irrigators; one for irrigators with less
than, and one for those with more
than, 15% overlap between adjacent run-to-run passes. (It is likely that most people will find the under 15% overlap is ok. And there may not be very much difference between them for most systems.)
We are aware that farmers are using a range of effluent application irrigation systems, but by far the most common are small travelling irrigators with rotating booms. You can download the guidelines and worksheets here>
What is involved?
The guidelines show how to lay out catch cans (buckets) to catch applied effluent, and how to perform calculations to determine the amount (rainfall depth equivalent) of effluent applied and its uniformity (evenness). There are interpretations to guide assessment of your results. The worksheets are designed to make recording and analysing your measurements easy.
What is different to normal irrigation calibrations?
A series of methods for calibrating other irrigation types is available on the irrigation calibration page
. They are designed to help you calibrate normal, clean water irrigation systems.
Normal irrigation is used to avoid drought stress, and there is a focus on potential under-application. It is used when the available soil moisture is getting used up. The standard uniformity measure looks at the lowest collected volumes and compares them to the overall average applied.
Effluent is nutrient and biology rich with a need to focus on potential over-application. And it might be applied when the soil is already pretty wet. So the uniformity measure compares the highest collected volumes with the average.
The normal irrigation guidelines do not have nutrient application built into the templates. But with a little thought and a look at the effluent guidelines, you can work out what to do!
Results from surveys
Page Bloomer Associates completed a national survey of farm dairy effluent applicators (SFF 07-016 Canterbury Dairy Effluent Efficiency Application) and results are now available on the site under "Projects". Click here for more>
We also ran a workshop for dairy farmers in the Toenepi Catchment study area where we trialed the IRRIG8Quick methods. Thanks to those farmers, we have a better set of guidelines and worksheets for you to use! The results can be viewed here>