Dynamics of Nitrogen Compounds in the Soil

The aim of the study was in Poland to check to what extend N leaching from the soil can be restrained by catch crop growing, whether N which has not been utilized by the first cereal crop grown after red clover, can be carried-over to next cereal crop by growing a catch crop and In Lithuania the research of nitrogen migration in model systems of untouched soil after application of organic fertilizers. To estimate, that catch crop growing reduced N - N0(3) concentration in the upper soil layer (reduction by 20-21%) but not in a medium soil layer (increase by 12%). The most significant reduction of N - N0(3) concentration was found in the third soil layer (by 63 - 68%). The changes of N - N0(3) concentration in a given soil layer were not depended on soil structure and humus content. Due to catch crop growing potential N - N0(3) losses were reduced on humus richer soil by 36 kg and on humus poorer soil by 30 kg. After application of organic fertilizers migration of nitrogen compounds in soil takes place slowly, at the speed of 0.2 cm per day. Correlation between concentrations of nitrogen compounds is strongest in the first layer of soil. Contrary correlation between concentrations of ammonium ions and nitrites was found in the second and third layers.