EFFECT OF COMPOSTED MANURE ON SOIL FERTILITY AND MAIZE (ZEA-MAYS) PRODUCTION - PRELIMINARY-RESULTS

The effects of composted manure utilised as an alternative fertiliser in maize forage production on soil microbial-biomass was studied. Five different field treatments (with and without atrazine) were compared: control (without fertiliser), fresh manure, composted manure, inorgan ic-N fertiliser (nitram), compost+nitram. Fresh and dry matter of fora ge biomass was determined at the end of growing season, and soil micro bial Cbiomass and microbial N-biomass were determined during crop cycl e. A decrease on forage yield was observed in fresh manure treatment w ithout atrazine, probably caused by strong competition for nutrient up take among crop, weeds and micro-organisms. The addition of inorganic fertiliser did not bring any significant increase in soil N-biomass du e to the high basal organic matter content of soil.