Soil Fertility in Organic Farming in the First Years After Transition

Abstract

In this paper soil fertility indices were compared on four organic farms with neighbouring fields under conventional farming. The organic farms were in the first years after organic transition. Results indicate that there were significant differences between farming systems in nitrate nitrogen (NO3-N), available phosphorus (AL-P2O5) and potassium (AL-K2O). However, there were no significant differences in organic matter (OM) and total N contents between organic and conventional systems, although higher, but not significantly higher, soil fertility indices were found in conventional farming. There were no significant differences between organic and conventional systems in C/N ratio, although wider C/N ratio was found on organic fields with low fertility status. Significantly lower level of NO3-N was measured in soil under organic farming. Lower, but not significantly lower, pH values was found on conventional fields compaired to organic. The organic fileds with low fertility status had significantly lower contents of available phosphorus and potassium (AL-P2O5 and AL-K2O). The soil texture also influenced soil characteristics