MODIFICATIONS OF CHEMICAL PROPERTIES OF MANURE IN THE PROCESS OF COMPOSTING

Apart from the production of sufficient food quantities modern agricultural production should produce high- quality food, but also preserve the environment, primarily by preserving the soil as a natural, renewable, but also exhaustible resource. Preservation of soil directly emphasizes the concern about elementary properties of soil affecting its fertility. One of the measures is usage of organic manure. Manure is used most often in practice, and the processes of decomposition depending on the way of maintenance and manure removal of the cattle, and the conditions in which such stack is amassed and kept are not often desirably directed. During implementation of such manure, the expected positive effects appear to be the negative ones. Five different manure types have been composted in the experiment (cattle manure, horse, pig and poultry) and the changes in the chemical properties have been monitored. During the process of composting significant changes have occured: pH level of initial compost materials has grown in all the composts (from 8 to over 9), except for the pig, which had the pH level below 7; EC had an average increase of 69%, and at the end of the research a very high EC was found out in the poultry (12.15 d•Sm-1 which is three times above the borderline values for substrates of container production) and horse (8.75 d•Sm-1 which is almost twice the value). The entire process of composting is characterized by the decrease of the portion of organic carbon (on the average for 19.62%), while the dynamics of the portion of the total N is vice versa (average increase by 38%). C•N ratio in the composts decreased, as expected, below 20:1 and the highest decrease is with the cattle manure with the highest initial C•N ratio. The increase of NO3- and decrease of NH4+ were established.