Biochemical changes and characteristics of organic matter transformation during composting process of vineyard prunings

The characteristics of changes of biochemistry and organic matter transformation of vineyard prunings composted in open wooden rotting boxes (V=0.25 m3) for 122 days at the treatments of N fertilizer added and no N fertilizer added were monitored by combinative means of chemical, Inductively Coupled Plasma Atomic Emission Spectrometer (ICPAES) and FTIR spectroscopy analyses. The results showed that the maximum temperature values reached of N fertilizer added and no fertilizer added were 76℃ at the third day of composting and 65℃ at the fourth day, respectively. The length of thermophilic ranges(≥50℃) of N fertilizer added and no fertilizer added remained for 21 and 7 days, respectively. The decomposition of organic materials was obviously divided into two phases, viz., earlier incipient rapid decomposition and mid-later slow decomposition. The rate of decomposition of N fertilizer added was rapider than no N fertilizer added. The decreases of the total C, total absolute N and the C:N ratio, and the increase of the N content were observed during composting. The relative decreases in OH, CH3 and CH2 groups, the increase in CO groups, the appearance of COO groups as the forms of carboxylic salts and PO groups as the forms of phosphatic salts, which indicate that the decreases of aliphatic compounds, the increases of aromatic compounds, and the OM mineralization during composting of vineyard prunings, and the finished and stabilized vineyard prunings compost rich in nutrients required by the crops was faster obtained in N fertilizer added than in no N fertilizer added. Vineyard prunings compost can be used as a quality environment friendly organic fertilizer or a conditioner of soil in agriculture.