Evaluation of maturity and fertilizer capacity of compost derived from swine solid fraction

The solid fraction of swine slurry resulting from mechanical separation has been co-composted with two organic materials: wheat straw and wood chips. Chemical parameters (C/N ratio, Humification Ratio, NH4-N content and NH4-N/NO3-N ratio) and biological assays (germination and plant growth tests on Lepidium sativum L., Raphanus sativus L. and Sinapis alba L.) have been used to evaluate the compost maturity. Compost fertilizing capacity has been evaluated with a long duration growth test carried out in pots with the most common crop of northern Italy, Zea mays L.. The analysis of chemical parameters and bioassays showed that both composts (with wheat straw and woodchips) are stabile and mature. The long duration growth test highlighted that both composts could take the place of the mineral fertilizers generally used as basal dressing in maize growing with environmental and economical advantages.