CALCULATION OF EFFECTIVE GAS FLUX FROM SOIL FOLLOWING BAND APPLICATION OF MANURE OR FERTILIZER

Greenhouse gases are emitted following application of manure and nitrogen-containing fertilizers to soil. Manure and fertilizers are often applied in subsurface bands in the soil, or in bands on the soil surface. This article presents a method that has been developed for calculating the effective gas flux for a multiple-band area to which manure or fertilizer has been applied in bands. The method has been developed for circular and rectangular flux chambers. In analyzing the method, a combination of CO(2) gas fluxes from a field experiment that gave a relatively low whole-plot effective flux and a combination that gave a relatively high whole-plot effective flux were used. For the lower-end flux situation, when the dimension of the flux chamber in the direction perpendicular to the band is considerably less than the band spacing, if the flux in a chamber that is centered on a band is assumed to be the whole-plot effective flux, then this assumption would overestimate the actual whole-plot effective flux by a considerable amount. The error of this type of assumption is reduced for the higher-end flux situation, regardless of flux chamber dimensions, and is reduced when the lower-end flux situation occurs and the dimension of the flux chamber in the direction perpendicular to the band is intermediate to nearly as large as the band spacing. The method in useful in calculating effective gas fluxes for whole plots to which manure or fertilizer has been band-applied.