The effect of organic mulches on the amount of organic carbon in the soil

Abstract

Natural organic mulch eventually breaks down and adds organic material back into the soil. The field experiment on organic mulches was carried out in the Pomological Garden of Aleksandras Stulginskis University (previously - Lithuanian University of Agriculture) (54°53rN, 23°50'E). The soil type - Calc(ar)i-Endohypogleyic Luvisol. Treatments of the experiment: factor A - mulch: 1) without mulch; 2) straw (chopped wheat straw); 3) peat (medium decomposed fen peat); 4) sawdust (from various tree species); 5) grass (regularly cut from grass-plots). Factor B - thickness of mulch layer: 1) 5 cm; 2) 10 cm. The influence of organic mulches was investigated in 2004-2009, the residual effect of mulches - in 2010-2011. The aim of the investigation was to evaluate the effect of different organic mulches and different thickness of mulch layer on soil organic carbon. The significant effect of peat mulch on soil organic carbon was established during the period of investigations. In 2009-2010 the significant effect of sawdust on soil organic carbon content was established. The thicker (10 cm) mulch layer significantly increased the amount of organic carbon in the soil. Very strong positive significant linear relationship (r = 0.994, P < 0.01) between organic carbon content incorporated with mulches and organic carbon content present in the soil plough layer was ascertained.