Carbon stock changes in drained arable organic soils in Latvia: results of a pilot study
Latvian State Forest Research Institute ‘Silava’, 111 Rigas str., LV-2169 Salaspils, Latvia
*Correspondence: arta.bardule@silava.lv
Abstract:
Drained arable organic soils in the most of European countries represent a minor part of the total area of farmlands, but these soils contribute significantly to national greenhouse gas budgets. The aim of the pilot study is to demonstrate methodology for determination of the changes of soil organic carbon stock after drainage of arable land on organic soil by evaluation of subsidence of the land surface from detailed historical pre-drainage topographic maps created during designing of drainage systems and LiDAR. Results of a pilot study show that ground surface level in arable land on organic soil has decreased by 0.8 cm annually after drainage, but soil organic carbon stock has decreased by 4.2 ± 3.3 tonnes C ha-1 yr-1. The results of a study show that pre-drainage topographic maps are suitable for estimation of organic layer subsidence after drainage. The estimated mean CO2 emissions are about 47% less than the default emission factor for drained arable organic soils in boreal and temperate climate zone provided by Intergovernmental Panel on Climate Change Guidelines for National Greenhouse Gas Inventories. The results substantiate the necessity to develop national methodology to estimate emissions from drained organic soils in cropland and grassland.
Key words:
carbon stock, drained agricultural land, LiDAR, organic soil, subsidence