Comparing of GHG emissions in galega and grassland ecosystems

Abstract

Most agricultural land lies under pasture (globally - 3488 Mha, or 69% of the land area; in Lithuania - 1.2 Mha, or 50 % of the land area). Conservation and accounting for GHG emission of grassland ecosystems is important to evaluate fluxes at the regional and ecosystem levels (Smith et al., 2007). These emissions were investigated in semi-natural grassland and in 20 year old galega {Galega officinalis) stands at the Lithuanian University of Agriculture in 2009 within the framework of the European Projects COST ES0804. The objective of the investigation was to determine the impact of fertilizer application on GHG emission of abandoned semi-natural swards compared to GHG emission from non fertilized galega stands. GHG emission measurements were made in the June-September period, when meteorological conditions were optimal for intensive plant and soil biota physiological processes, in the absence of frosts. Observed GHG emissions decreased from June till September (HTC ranged from 2.0 to 0.9) and were nearly the same in semi-natural and galega grasslands. Non-fertilized galega stands confer benefits for soil and landscape conservation without raising GHG emissions. Appropriate fertilizer rates should not exceed N60P40K50 to maintain soil fertility. In order to prevent abandoned semi-natural grassland from forestation the use of sheep and goats should be considered.