Suitable parameters for soil organic matter changes evaluation in agro-ecosystems

Abstract

In period 1999-2003, we studied suitability of new parameters for determination of soil organic matter (SOM) changes in ecological (ES) and integrated (IS) fanning systems established in 1990 in the experimental station Slovak University of Agriculture in Nitra. The lability of carbon (L ) was higher in spring (0.183) than in autumn (0.1.58) in both, systems. The lability of nitrogen (LN) was higher in IS (0.080) than in ES (0.074). Carbon management index (CMI) values were increasing more intensively in IS (from 108.7 to 118) than in ES (from 109.3 to 113.3). Higher percentage portions of potentially mineralizable nitrogen (NL) from, total (NT.) were in IS than in ES. It means that higher SOM sources are in ES than IS, but according to parameters LC, CMI, LN, more intensive changes in SOM sources can be supposed in IS than in ES. We recorded influence of average annual temperature on parameters of labile carbon (r = -0.79, P < 0.01), non-labile nitrogen (r = 0.76, P < 0.01), as well as the year precipitation sum on CMI (r = -0.58, P < 0.01), labile nitrogen (r = 0.72, P < 0.01) and LN (r = 0.61, P < 0.01). From the point of sustainable development the parameters labile carbon, LC and non-labile nitrogen (NNL) were the most suitable for the assessment of SOM changes in farming systems.