Relationship between CO emissions and soil properties of differently tilled soils.

Different tillage technologies have different effects on CO emissions from soil. Unfortunately, little information exists about the impact of different types of tillage as compared with no-tillage, and the main controls. The aim of this research is to determine the relationship between physicomechanical, chemical and biological properties of soil and CO emissions from differently tilled soils under the climatic conditions of central Lithuania before and after autumn tillage. The studies were conducted in 2009-2012 and 2014 at the Experimental Station of Aleksandras Stulginskis University in Central Lithuania. Different tillage technologies were applied: deep ploughing at 23-25 cm depth (DP); shallow ploughing at 12-15 cm depth (SP); deep cultivation with a cultivator at 25-27 cm depth (DC); shallow cultivation with a disc harrow at 12-15 cm depth (SC); and no-tillage (NT). The correlation of physicomechanical, chemical and biological soil properties with CO emissions was determined. During all the experimental period total CO emissions from soil in DP, SP, DC, SC and NT technologies were respectively 6.05, 4.25, 4.97, 4.42, 3.94 μmol m s before autumn soil tillage and 29.88, 22.50, 16.73, 13.72, 10.00 μmol m s after autumn tillage. Negative correlation between soil temperature and CO emissions before the autumn tillage from soil was evidenced (r = -0.98). A strong negative correlation between soil respiration and total soil porosity was observed. Correlation between aeration soil porosity and CO emissions was strong. After autumn tillage, the strongest correlations were found between soil penetration resistance and respiration in the upper (r = -0.75) and deeper (r = -0.71) layers. In autumn, a significant strong correlation (r = 0.78) between soil respiration and aeration porosity was obtained in the upper soil layer under ploughing or cultivation. This study revealed that CO emissions were significantly higher immediately after autumn ploughing technologies compared to deep and shallow cultivation and no-tillage.