Changes in the physical distribution (particle size and the state stability against decomposition) of the organic carbon pool in tilled layers of Hungarian field soil under different tillage treatments were studied. Three years after starting the experiment, soil samples were fractionated (they were taken in March 2005) by their particle size a
...nd density. The treatments caused well measurable, significant effects on two fractions of intra-microaggregate organic matter (53-250μm particle-sized, well and less decomposition-resistant pools) and onto their relative rate in the organic carbon pool of the whole soil. Different tillage treatments caused different distributions in the organic matter fractions. In regularly intensely cultivated soils evolve different physical structure, particle size-distribution, which reduce the soil fertility and its resistance against outer impacts.