Soil Greenhouse Gas Emissions Affected by Irrigation, Tillage, Crop Rotation, and Nitrogen Fertilization

Management practices, such as irrigation, tillage, cropping system, and N fertilization, may influence soil greenhouse gas (GHG) emissions. We quantified the effects of irrigation, tillage, crop rotation, and N fertilization on soil CO(2), N(2)O, and CH(4) emissions from March to November, 2008 to 2011 in a Lihen sandy loam in western North Dakota. Treatments were two irrigation practices (irrigated and nonirrigated) and five cropping systems (conventional-tilled malt barley [Hordeum vulgaris L.] with N fertilizer [CT-N], conventional-tilled malt barley with no N fertilizer [CT-C], no-tilled malt barley–pea [Pisum sativum L.] with N fertilizer [NTPN], no-tilled malt barley with N fertilizer [NT-N], and no-tilled malt barley with no N fertilizer [NT-C]). Th e GHG fluxes varied with date of sampling and peaked immediately after precipitation, irrigation, and/or N fertilization events during increased soil temperature. Both CO(2) and N(2)O fluxes were greater in CT-N under the irrigated condition, but CH(4) uptake was greater in NT-PN under the nonirrigated condition than in other treatments. Although tillage and N fertilization increased CO(2) and N(2)O fluxes by 8 to 30%, N fertilization and monocropping reduced CH(4) uptake by 39 to 40%. The NT-PN, regardless of irrigation, might mitigate GHG emissions by reducing CO(2) and N(2)O emissions and increasing CH(4)uptake relative to other treatments. To account for global warming potential for such a practice, information on productions associated with CO(2) emissions along with N(2)O and CH(4) fluxes is needed.