Effect of long term organic and conventional fertilization method on chosen soil chemical properties

The aim of the study was to compare a long term effect of oppositional fertilization methods,organic vs. conventional,on chosen soil chemical properties. Soil samples were collected from organic farms with at least 10-years history of organic management and from neighboring conventional farms. In total soil samples from 66 farms distributed all over Poland were collected. The following properties were analyzed: organic carbon (Corg),total nitrogen (Ntot),pH,exchangeable forms of P,K and Mg. In general organic management resulted in slightly higher soil pH. Bigger differences were found in case of C and N content. Thanks to organic fertilization method in loamy and clay soils C content was higher by 13.5% and N content was higher by 20.3%. The same tendency,although not so marked,was found on sandy soils. Conventional fertilization resulted in higher content of exchangeable P,especially on sandy soils. Almost the same content of exchangeable K was found on both farm types. Higher amounts of exchangeable Mg was found on organic farms on each soil type: sandy,loamy and clay. In the same time bigger disproportions of Mg content were found on organic farms (30-112 mg Mg kg -1) than on conventional farms (30-87 mg Mg kg-1).