*Stay Tuned for Many More Extensive and Successful Results from the 2013 Season Coming Soon!
Quantifying the yield benefits from Variable Rate Irrigation is almost as important as the implementation itself. CropMetrics was the first to develop a ’30-30′ VRI field trial to do just that. To insure near identical field and climate conditions, the trials are conducted in single fields using the same center pivots and same irrigation schedules (timing and base water amounts) with data collected using the same yield monitors. Besides the fields soil type and topography variability, the only other variable that differed was the site-specific rate of applied irrigation application depth. VRI Speed Control prescriptions were generated to adjust the base irrigation application depths to precisely match the soil water holding capacities and topographies of the corresponding “pie-shaped” irrigation sectors. This would then alternate every 30 degrees with the growers “legacy” flat rate irrigation application depths that are consistent with standard irrigation practices used today.
The first two examples below show multiple corn hybrids planted side-by-side then replicated within a single field. CropMetrics is partnered with leading seed companies to not only test the yield benefits of VRI, but to also better understand each individual hybrid relationship to differing water application rates.
The next report highlights yield results by a straight comparison of 2009 corn yield data from flat rate irrigation to 2011 corn yield data from VRI Speed Control. The east half of the field was analyzed using Advanced Data Analysis. The report shows a yield improvement in 2011 as high as 46.5 bushels per acre in certain areas of the field.
Using landscape change and slope layers to identify the change in topography from west to east, irrigation was spatially managed to address over watering and runoff on the lower east half of the field. Not only were the 2011 yield results significantly higher with VRI Speed Control but the runoff of water and nitrogen fertilizer was significantly reduced.
The next series of reports highlight yield results from VRI trials representing single varieties and how they perform within specific light or heavy soil types. When utilizing VRI, irrigation application rates will adjust the greatest in the areas of the field with the most variance on high and low ends (both soil type and topography differences).
Understanding these changes, we are able to analyze specific water rates in relation to these individual field variables. These yield results will not only tell us how much VRI benefit we received in each soil type or landscape position, but it will also assist in identifying the optimal application rate on each individual acre so we can fine tune our VRI prescriptions the following year. Utilizing the CropMetrics Advanced Data Analysis tools, growers continue to improve their management techniques year-after-year. The first two reports utilized VRI Zone Control with Valley VRI while the third image utilized VRI Speed Control.
The growers legacy flat rate irrigation application depths were set to apply 1″ of water on corn alternating with the fully optimized VRI prescriptions every 30 degrees. Once again, the goal of these VRI Yield Trials, with all other variables being the same, was to demonstrate the overall effectiveness of using data, software, agronomy and control to manage irrigation for optimum water use efficiency and maximum yield.
See the video of two Nebraska growers utilizing the CropMetrics precision VRI program with local Precision Data Specialist support and hear about the benefits and value they are receiving by implementing this precision technology on their own farms.