title: Nitrogen, tillage, and crop rotation effects on carbon dioxide and methane fluxes from irrigated cropping systems.
abstract: Long-term effects of tillage intensity, N fertilization, and crop rotation on carbon dioxide (CO(2)) and methane (CH(4)) flux from semiarid irrigated soils are poorly understood. We evaluated effects of: (i) tillage intensity [no-till (NT) and conventional moldboard plow tillage (CT)] in a continuous corn rotation; (ii) N fertilization levels [0-246 kg N ha(-1) for corn (Zea mays L.); 0 and 56 kg N ha(-1) for dry bean (Phaseolus vulgaris L.); 0 and 112 kg N ha(-1) for barley (Hordeum distichon L.)]; and (iii) crop rotation under NT soil management [corn-barley (NT-CB); continuous corn (NT-CC); corn-dry bean (NT-CDb)] on CO(2) and CH(4) flux from a clay loam soil. Carbon dioxide and CH(4) fluxes were monitored one to three times per week using vented nonsteady state closed chambers. No-till reduced (14%) growing season (154 d) cumulative CO(2) emissions relative to CT (NT: 2.08 Mg CO(2)-C ha(-1); CT: 2.41 Mg CO(2)-C ha(-1)), while N fertilization had no effect. Significantly lower (18%) growing season CO(2) fluxes were found in NT-CDb than NT-CC and NT-CB (11.4, 13.2 and 13.9 kg CO(2)-C ha(-1)d(-1) respectively). Growing season CH(4) emissions were higher in NT (20.2 g CH(4) ha(-1)) than in CT (1.2 g CH(4) ha(-1)). Nitrogen fertilization and cropping rotation did not affect CH(4) flux. Implementation of NT for 7 yr with no N fertilization was not adequate for restoring the CH(4) oxidation capacity of this clay loam soil relative to CT plowed and fertilized soil.
authors.affiliation: Dep of Agronomy, Forest and Land Management, Univ. of Turin, via L. da Vinci 44, 10095 Grugliasco (TO), Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Alluvione
authors.forename: Ardell D
authors.initials: AD
authors.lastname: Halvorson
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Del Grosso
mesh_terms: D000383:Agriculture; D002245:Carbon Dioxide / Q000032:analysis* / Q000737:chemistry; D005308:Fertilizers; D008697:Methane / Q000032:analysis* / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D005308:Fertilizers; D002245:Carbon Dioxide; D009584:Nitrogen; D008697:Methane