Linking Organic Carbon, Water Content, and Nitrous Oxide Emission in a Reclaimed Coal Mine Soil

Mine-land reclamation for biomass production is often achieved by means of large applications of N and organic C with amendments that could create soil conditions favorable for N2O production and emissions. To investigate this possibility, we conducted a laboratory experiment using mine soil collected from an active surface coal mine site near Philipsburg, Pennsylvania. During a 37-d incubation period, we measured N2O and CO2 fluxes from non-amended soil and from soil amended with ammonium nitrate (L+F), composted poultry manure (Comp), poultry manure alone (Man) and mixed with 3 rates of paper mill sludge (PMS) to obtain carbon to nitrogen ratios of 14, 20 and 27 (Man+PMS14, 20 and 27), each at 60% and 80% water filled pore space (WFPS). Results showed that manure alone leads to a greater emission of N2O under laboratory conditions than with L+F. However, composting manure effectively reduced the emissions compared to that of L+F despite a large addition of organic C and N. Composted manure-treated soil emitted less than all other manure-based treatments at both 60% and 80% WFPS. The emissions were greater from soil amended with the Man+PMS treatments compared to non-amended and L+F-amended soil, and it increased during periods of intense microbial activity created by the application of manure and PMS. Higher water content increased emissions particularly during periods of intense microbial activity coupled with inorganic N availability. Cumulative N2O emissions from manure-treated soils represented less than 01% loss of total applied N. Copyright (c) 2014 John Wiley & Sons, Ltd.