Agroecosystems’ contribution to seasonal carbon exchange in temperate climate of Central Lithuania

Abstract

Soil CO2 emissions comprise the biggest part of the global C-cycle increasing the anthropogenic CO2 emissions into the atmosphere. Therefore the correct choice of agro technologies and crops contributing to the mitigation of the climate change is becoming an important challenge for the agro sector. The comparison of both farm-ing type, i.e. organic (OF) and conventional (CF), and environmental impact on carbon exchange in ley (G) and winter wheat (W) agroecosystems were carried out at the Training farm of the Aleksandras Stulginskis University in 2014 – 2015. This research revealed that both organic and conventional agriculture has the potential to emit respiratory carbon dioxide (CO2), making croplands important in terrestrial car-bon (C) cycles, where they dominate in the anthropogenized landscape. It was found that respirational emissions altered depending on the vegetation period, particular month, and changing environmental conditions in both farming types. Regardless of the crop species a strong positive correlation between respiration CO2 emissions and soil temperature (r =0.8, p=0.25), strong negative with soil moisture content (r=-0.7, p=0.04) and medium with soil electrical conductivity (r =0.3, p=0.47) was found. Organic farming technologies decreased mean soil respiration by 9% (p=0.31) and 16% (p=0.55) in ley and wheat agroecosystems, respectively, comparing to the conventional farming. Strong positive correlation between soil respiration and temperature (r=0.8, p=0.25), moisture content (r=-0.7, p=0.04), electrical conductivity (r =0.3, p= 0.47) confirmed the impact of soil physical parameters on CO2 emissions from soil to atmosphere. As soil respirational emissions differed between the as-sessed agroecosystems, thus it can be controlled by means of optimizing sustainable agrotechnologies or choice of crop species in rotation systems.