THE IMPACT OF CROP ON GHG EMISSIONS FROM CLAY SOILS:CASE STUDY OF LATVIA

Agriculture is a source of three primary GHG: CO₂, CH₄ and N₂ O. In order to reduce agricultural GHG emissions, agricultural practices have to promote sustainable land management by helping to prevent soil erosion and creating the potential to increase soil carbon stock. Sustainable soil management includes reducing tillage and introducing legumes in crop rotation. The aim of the study is to identify the impacts of the soil tillage and the cultivated crops on formation of GHG emissions. The study site has 24 experimental fields where two types of soil tillage have been used and four crops where grown (wheat Triticum aestivum, rape Brassica napus, beans Vicia faba and barley Hordeum vulgare). Soil humidity, soil temperature and measurements of GHG emissions have been carried out during the plant vegetation period from 2018 to 2020. GHG emissions where measured using Picarro G2508. A total of 460 measurements of GHG emissions were made in 2018, 2019 and 2020. The minimum value of N₂ O emission is-19.5 g ha^-1 day^-1, but the maximum is 273.4 g ha^-1 day^-1 . CH₄ emission has a minimum value of-84.8 g ha^-1 day^-1, and a maximum of 514.1 g ha^-1 day^-1. The minimum value of CO₂ emission is-13.0 kg ha^-1 day^-1, but maximum of 1026.7 kg ha^-1 day^-1. The results of CO₂, CH₄ and N₂ O emissions show a significant discrepancies between the arithmetic mean and the median values which indicates the observed extreme values. Kruskal-Wallis test showed statistically significant differences in GHG emissions by crop groups.