USE OF CONTROLLED RELEASE FERTILIZERS AND NITRIFICATION INHIBITORS TO INCREASE NITROGEN USE EFFICIENCY AND TO CONSERVE AIR ANDWATER QUALITY

Abstract

Field trials on controlled release fertilizers (CRF) and a nitrification inhibitor (NI) were conducted in order to show their potential to increase N use efficiency (NUE) and to conserve air and water quality. For this purpose, flood irrigated barley grown on a clay soil (Colorado, USA), center-pivot irrigated potato grown in a sandy field (Colorado, USA), and corn grown on a loamy soil at a large scale lysimeter (Fukushima, Japan) were selected. NI (dicyandiamide) and CRF (polyolefin coated urea) were capable of reducing N₂O emissions from urea applied to the barley field by 81 % and 35 %, respectively. Total N fertilizer losses averaged 15 and 10 % in the NI and urea treatments, respectively. On the other hand, those from the CRF treatment averaged only 1.9 %, indicating that CRF showed the highest potential to increase N use efficiency. The trials in the potato field demonstrated that CRF could markedly increase NUE and tuber yields. A single basal application of CRF at planting (N rate, 112 kg ha⁻¹) produced tuber yields comparable with those of traditional fertilizer applications (112 kg N ha⁻¹)by basal dressing, 90 kg N ha⁻¹ by topdressing and 67 kg N ha⁻¹ by 8 fertilizations). The urea and CRF plots in the corn fields showed similar N₂O emission patterns, having two high emission periods following the basal and topdressed N applications in the urea plots and the enhanced N release from a short linear formulation and a long sigmoidal formulation in the CRF plots, respectively. However, the total N₂O emission value of the CRF plots was almost one third of that of the urea plots. The plant recovery of CRF N was almost two times of that of urea N. Finally, the authors discussed that contributions of CRF and NI to conserve air and water quality are basically due to maximizing NUE and reducing the N fertilization rate.

Keywords:

• Barley
• Controlled release fertilizer
• Corn
• DCD
• Nitrogen use efficiency
• Nitrous oxide
• Polyolefin coated urea
• Potato
• Water quality

ACKNOWLEDGMENTS

The authors thank Ms Mary Smith, Ms. Susan Crookall, Mr. Larry Tisue, Ms Ashley Fenno, Ms. Anita Kear, Mr. DaveWright, Ms. Mebrat Gesese, and Mr. Michael Golinski for their capable assistance during collection and analysis of soil and plant samples; Mr Donald “Smokey Barker” from USDA-NRCS for coordination of activities with NRCS; Mr. James Mietz from USDA-NRCS-RC&D for coordination of activities with the Center Soil Conservation Districts. We are grateful for the use of the Colorado State University Horticultural farm and the help of Dana Christensen. We thank the support grant by the Chisso America Inc. and for supplying MEISTER. We also thank the Center Soil Conservation Districts in the San Luis Valley for their support with EPA-319 matching funds. We also thank Alvin and Amy Kunugi, San Luis Valley farmers and Larry Kawanabe USDA-NRCS, San Luis, CO, for their cooperation in the site two study.

Notes

^†Manufacturers names are necessary to report factually on available data, however the USDA neither guarantees nor warrants the standard of the product; and the use of a given name by the USDA does not imply approval of that product to the exclusion of others that may be suitable.