COMPOST PRODUCTION AND COMPOSTED MANURE QUALITY EVALUATION

Composted manure can have an important role in production of substrate for growing seedlings, which would make the organic waste management more cost-effective, but also decrease the cost of seedlings production. Production of composted manure is of significant importance for family farms as well and even more so for farms practicing integral and organic agriculture. This research aims to establish the changes in physical and chemical characteristics of manure from cattle, horse, pig and poultry production during the composting process. The composting process was stopped after 9 months, when the compost was stable (2-4 mg CO₂-C g^-1 OM d^-1). Analysis of physical and chemical characteristics was conducted according to TMECC 03.09-A methods. Temperatures necessary for disinfection of the compost material were developed during the process. The content of ash also significantly increased (37% on average) while the portion of the organic matter decreased. Compared to the initial material, the concentration of P, K, Ca and Mg after 9 months of composting was significantly increased in all composts, namely P and K 42% on average and Ca and Mg 71 and 72% respectively. At the end of composting, all the composts had C/N ratio below 20:1, which indicates their stability. However, some researchers think that the ratio between the final and initial C/N (<0.6 to 0.75) is a better indicator of compost maturity, and according to that all the composts, with the exception of the chicken one (0.86), were mature. When using NH₄⁺-N/NO₃^--N ratio as the indicator of compost stability (<0.16), the composts derived from cattle (semi-mature and fresh) and horse manure were stable (<0.14), composted pig manure almost stable (0.64), while the composted chicken manure was still very unstable (14.75).