title: Management of irrigation frequency and nitrogen fertilization to mitigate GHG and NO emissions from drip-fertigated crops.
abstract: Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors (water-filled pore space, NH4(+) and NO3(-)) regulating the emissions of greenhouse gases (i.e. N2O, CO2 and CH4) and NO from agroecosystems can easily be manipulated by drip fertigation without yield penalties. In this study, we tested management options to reduce these emissions in a field experiment with a melon (Cucumis melo L.) crop. Treatments included drip irrigation frequency (weekly/daily) and type of N fertilizer (urea/calcium nitrate) applied by fertigation. Crop yield, environmental parameters, soil mineral N concentrations and fluxes of N2O, NO, CH4 and CO2 were measured during 85 days. Fertigation with urea instead of calcium nitrate increased N2O and NO emissions by a factor of 2.4 and 2.9, respectively (P<0.005). Daily irrigation reduced NO emissions by 42% (P<0.005) but increased CO2 emissions by 21% (P<0.05) compared with weekly irrigation. We found no relation between irrigation frequency and N2O emissions. Based on yield-scaled Global Warming Potential as well as NO cumulative emissions, we conclude that weekly fertigation with a NO3(-)-based fertilizer is the best option to combine agronomic productivity with environmental sustainability. Our study shows that adequate management of drip fertigation, while contributing to the attainment of water and food security, may provide an opportunity for climate change mitigation.
authors.affiliation: ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain. Electronic address: diego.abalos@upm.es.
authors.forename: Diego
authors.initials: D
authors.lastname: Abalos
authors.affiliation: ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Sanchez-Martin
authors.affiliation: ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Garcia-Torres
authors.affiliation: Department of Soil Quality, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands.
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: van Groenigen
authors.affiliation: ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Vallejo
mesh_terms: D057914:Agricultural Irrigation / Q000379:methods*; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control* / Q000706:statistics & numerical data; D002245:Carbon Dioxide / Q000032:analysis; D057231:Climate Change; D005308:Fertilizers / Q000032:analysis / Q000706:statistics & numerical data; D017752:Greenhouse Effect; D009609:Nitrous Oxide / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D005308:Fertilizers; D002245:Carbon Dioxide; D009609:Nitrous Oxide
keywords: Drip irrigation; Fertigation; Greenhouse gases; Irrigation frequency; Nitric oxide; Urea