Greenhouse gas emissions from selected horticultural production systems in a cold temperate climate

摘要

Greenhouse gas (GHG) emissions from arable soils are released to the atmosphere in the form of nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). These soil emissions were measured from three horticultural production systems in Quebec and Ontario, Canada, for the following crops: (1) cranberry production in an artificial bog on sandy soil; (2) tomato production on a conventionally farmed loamy sand soil; and, (3) onion production on an organic soil. In-situ soil N2O, CO2 and CH4 fluxes were measured at each site using the non steady-state static chamber method. Tomato production on the loamy sand and onion production on the organic soils were the greatest producers of soil GHG emissions, with highest global warming potentials of 11,000 kg CO2-eq ha(-1) and 7800 kg CO2-eq ha(-1), respectively. The cranberry crop had the lowest global warming potential (2700 kg CO2-eq ha(-1)). Water management (water table depth, subsurface and surface drip irrigation) had a negligible impact on soil GHG emissions. The main factors influencing the production of N2O were spring thaw, rate and timing of inorganic fertilizers, and precipitation. Soil CO2 fluxes were primarily governed by soil temperature. Soil CH4 fluxes were low, as the soils from all crops were both oxidizing and producing CH4 simultaneously. Production of CH4 increased when the cranberry fields were flooded. Organic and mineral soils produced comparable amounts of soil greenhouse gas emissions.