Effects of climatic factors and soil management on the methane flux in soils from annual and perennial energy crops

Abstract

Methane flux rates were measured on a loamy sand soil within perennial and annual energy crops in northeast Germany. The study was performed in closed chambers between 2003 and 2005 with four measurements per week. A mixed linear model including the fixed effects of year, rotation period, crop and fertilisation was applied to determine the influence of climatic factors and soil management on the CH4 flux. Soil water content and air temperature were added as co-variables. With the exception of air temperature, all fixed effects and the co-variable soil water content influenced the CH4 flux. The soil of annual crops consumed 6.1 μg CH4 m−2 h−1, significantly more than the soil of perennial crops with 4.3 μg CH4 m−2 h−1. It is suggested that soil water content plays the key role in CH4 flux between pedosphere and atmosphere. In the range of water contents between 5% and 15%, our model describes that a soil water content increase of 1% induces a net emission of 0.375 μg CH4 m−2 h−1. As the soil of the experimental field was well-drained and aerobic, it represented a net sink for CH4 throughout the study period.