Seasonal and soil-type dependent emissions of nitrous oxide from irrigated desert soils amended with digested poultry manures.

Expansion of dryland agriculture requires intensive supplement of organic fertilizers to improve the fertility of nutrient-poor desert soils. The environmental impact of organic supplements in hot desert climates is not well understood. We report on seasonal emissions of nitrous oxide (N2O) from sand and loess soils, amended with limed and non-limed anaerobic digestate of poultry manure in the Israeli Negev desert. All amended soils had substantially higher N2O emissions, particularly during winter applications, compared to unammended soils. Winter emissions from amended loess (10-175mgN2Om-2day-1) were markedly higher than winter emissions from amended sand (2-7mgN2Om-2day-1). Enumeration of marker genes for nitrification and denitrification suggested that both have contributed to N2O emissions according to prevailing environmental conditions. Lime treatment of digested manure inhibited N2O emissions regardless of season or soil type, thus reducing the environmental impact of amending desert soils with manure digestate.