2019 Crop Production Clinic and Nebraska Crop Management Conference Proceedings
Profit and Nitrogen Use Efficiency Gain Using Sensor-Guided Fertigation
- Fertigation timing determined by crop sensors improves profit and nitrogen use efficiency (NUE) over current best management practices.
- Farm scale implementation of sensor-based fertigation has been shown to improve profit and NUE compared to grower management.
- Large scale variability at farm scale
- Implemented three years of sensor- and model-informed fertigation treatments at SCAL (Clay Center) and WCREC (North Platte).
- Check (5 lbs of N/acre as starter only).
- High N Reference (non-N limiting treatment).
- UNL algorithm (current N rate BMP, one time in-season sidedress informed by yield goal and N credits).
- Holland-Schepers (H-S) (sensor-BMP similar to Project SENSE, one time in-season sidedress directed by sensors) (Holland and Schepers, 2010).
- Reactive-fixed fertigation (fertigation directed by sensors: react to deficiency, N rate fertigated is fixed).
- Reactive-model fertigation (fertigation directed by sensors: react to deficiency, N rate fertigated is determined by crop computer model).
- Slow release reactive-model fertigation (initial N applied as polymer-coated urea [slow release], fertigation directed by sensors: react to deficiency, N rate fertigated is determined by crop computer model).
- Model-fertigation (not sensor informed, proactive N management is informed by crop model).
- All but Check received an initial base rate of N to maintain N sufficiency until sensors become reliably effective at V8.
- N was applied as UAN with exception of the slow release treatment that received slow release nitrogen as the initial base rate.
- Sensor based methods use sufficiency index (SI) to indicate level of N stress.
- Conclusion of three-year (five site years) study confirms that sensor fertigation treatments are consistently the most profitable and efficient methods of applying N compared to current best management practices (BMPs) (Figures 1 and 2).
- Sensor-based N management methods are more efficient that current BMPs.
- Sensor-based sidedress application varied in success between sites and years.
- In 2016 at SCAL site, the reactive-slow release-fertigation treatment did not have a corrected model for slow fertilizer N release. This resulted in excessive N application that resulted in a less profitable application. In 2017, a corrected slow release model was added, and the results indicate that in 2017 and 2018, this method was both profitable and efficient compared to current BMPs.