The relationship between crop residues chemical composition, decomposition in the soil and environmental conditions

Abstract

The experiments of decomposition of crop residues were carried out in the Experimental Station of the Lithuanian University of Agriculture in model field experiment during the period of 2003–2005. The soil of experimental site is Endocalcari-Epihypogleyic Cambisol (sicco) (CMg-p-w-can). Investigated decomposed in the soil for the different duration (from 3 to 26,5 months) above and below ground residues of these crops: winter oilseed rape, spring oilseed rape, winter wheat, and red clover. The aim of the investigation has been to establish oilseed rape residues decomposition intensity in the soil and dependence on residue chemical composition also environmental conditions in comparison with wheat and clover residues. Experiment data show that decomposition in the soil of stubble and roots of winter and spring oilseed rape is slower, because of the higher content of lignin as compared with their threshing remains or stubble and roots of winter wheat and red clover. It was estimated positive correlation (r = from 0,497* to 0,944**) between decomposition intensity of winter and spring oilseed rape and average temperatures of weather and soil, also sum (≥5°C) of these temperatures. Decomposition intensity of oilseed rape roots positively correlated (r = from 0,571** to 0,848**) with these indices also precipitation. Decomposition intensity of oilseed rape threshing remains and clover stubble negatively correlated (r = from -0,693** to -0,753**) with the content of lignin. Correlation between these indices in decomposing roots of wheat and cover was r =-0,486* and r =-0,563*, accordingly.