Fertilizer management effects on nitrate leaching and indirect nitrous oxide emissions in irrigated potato production

• Published in: Journal of environmental quality Vol. 40; no. 4; pp. 1103 - 1112
• Main Authors: Venterea, Rodney T, Hyatt, Charles R, Rosen, Carl J
• Format: Journal Article
• Language: English
• Published: United States The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc 01-07-2011; American Society of Agronomy
• Subjects: Agriculture - methods; best management practices; Climate; cropping systems; Emissions; emissions factor; environmental impact; Environmental Monitoring - methods; Experiments; Fertilizers; Fertilizers - analysis; Growing season; irrigated farming; irrigation; labor; Leaching; Minnesota; Moisture content; nitrates; Nitrates - analysis; Nitric oxide; nitrogen; Nitrous oxide; Nitrous Oxide - analysis; nutrient management; Polymers; Polymers - chemistry; Potatoes; preplanting treatment; Residual soils; soil; Soil - analysis; Soil sciences; Soil water; Solanum tuberosum - growth & development; split application; Studies; Urea; Urea - chemistry; water balance; Water Pollutants, Chemical - analysis; Water pollution
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2010.0540

Potato is a nitrogen (N) intensive crop with high potential for nitrate (NO3-) losses, particularly when irrigated. The high leaching potential also represents a potential source of indirect nitrous oxide (N2O) emissions resulting from the transformation of NO3- to N2O after it leaves the fertilized field. Best management practices (BMPs) for potato production attempt to minimize N losses by better temporal matching of soil N availability with crop N demand. The objective of this study was to quantify NO3- leaching and indirect N2O emissions in an irrigated potato cropping system managed using three different BMPs, consisting of (i) conventional split application (CSA) of soluble fertilizer and (ii, iii) single pre-plant applications of two different polymer-coated urea products (PCU-1 and PCU-2), each applied at 270 kg N ha-1. Over three consecutive growing seasons, rates of NO3- leaching were quantified using porous cup sampling and water balance modeling. Indirect N2O emissions were estimated using published emissions factors. Annual rates of fertilizer-induced NO3- leaching ranged from 0.6 to 8 % of the amount of applied N. Indirect N2O emissions were estimated to be 10 to 30% of direct N2O emissions based on previous measurements from the same experiment. The PCU treatments did not increase NO3- leaching or indirect N2O emissions compared with the CSA treatment. These results indicate that the additional labor and expense associated with multiple split applications can be avoided though the use of single pre-plant PCU applications, while maintaining yields and preserving the same level of environmental impact.