Emissions of CO_2 and N_2O from volcanic soil under different crop management using closed non-fixed chambers

摘要

Agriculture soils may be a potential source of greenhouse gases, however it is not directly estimated yet in countries like Chile, which has special soil and climate conditions for a competitive agricultural activity and particular nutrient cycling patterns and processes in volcanic soils. The present work shows the first data of CO2 and N_2O fluxes estimated from direct gas samples of passive chambers on volcanic soils in a crop system of Southern Chile. Gas samples were obtained from a oat-wheat rotation in a volcanic soil surface in Chile (36° S, 72° W) under two treatments of N fertilization (150 kg N/ha NH_4~+-and NO_3~--N, respectively) and two lime dose treatments (0,5 and 1 Ton lime/ha, respectively), from closed non-fixed chambers and fluxes of CO_2 and N_2O were estimated from a gas chromatograph concentration in fiinction of time during gas accumulation in the chambers headspace in a period of 1 year. Soil variables, including temperature, water content and mineral N content were registered in order to check correlations with gas fluxes. Results show low emissions of GHG from volcanic soils of Chile and no important influences of some agriculture management and environmental variables.