EFFECT OF LAND CONSERVATION ON CONTENT OF ORGANIC CARBON AND TOTAL NITROGEN IN SOIL

Soil is an extremely valuable component of ecosystems. Even during a break in intensive soil cultivation planned for a few years, the set-aside land should be given the best possible protection. The biomass left on fallow fields is a priceless source of humic compounds, which entails positive influence on resources of nutrients, their mobilisation and availability to future crops. The field experiment comprised five treatments: 1 bare fallow, 2 a plot swarded with goat's rue (Galega orientalis Lam.), 3 natural fallow, 4 a plot swarded with a mix of goat's rue (Galega orientalis Lam.) and aweless brome (Bromus inermis), 5 a plot swarded with aweless brome (Bromus inermis). During the experiment, agronomic treatments were limited to mechanical weeding of the bare fallow. Plant material was sampled from the swarded plots for chemical analyses. Each year, after the growing season finished, soil samples were taken. The soil was sampled at the depth of 0-25 cm. The tests showed that the way set-aside and fallow land is maintained significantly modified both the total nitrogen and organic carbon concentrations in soil. Goat's rue and its mixture with aweless brome most evidently favoured increased concentrations of organic carbon and total nitrogen. Bare fallow prove to be the least favourable solution. The tests have also demonstrated that the amount of organic carbon compounds accumulated in soil depended on the biomass of plants on a given set-aside field and the nitrogen accumulated in that biomass.