THE EFFECT OF TURNING FREQUENCY ON SOME COMPOST QUALITY

Abstract

Composting of organic materials (chicken manure mixed with sawdust) was performed using turned windrow method. The aim was to investigate the effect of turning frequency on some physicochemical properties of the final product of organic materials. Three turning frequency treatments were: no turning (TF0 or static compost), turning every 3 days (TF3) and every 7 days (TF7). The initial physicochemical properties of organic materials were determined. The moisture content of the treatments was adjusted to about 55% at the beginning of composting and no moisture adjustment was done thereafter. The results showed that turning frequency significantly affected moisture content (P<0.05), total organic carbon, total nitrogen and carbon to nitrogen ratio of composting piles. Losses were observed in moisture content (54.42-70.24% of the initial moisture content), total organic carbon (18.37-36.60% of the initial total carbon) and total nitrogen (1.01 and 14.61% of the initial total nitrogen for TF0 and TF3, respectively, but it increased 8.40% at the TF7 treatment). The loss of total organic carbon was attributed to organic matter degradation, while those of total nitrogen were largely attributed to ammonia (NH3) volatilization. Moisture loss with turning frequency increased. All the treatments reached maturation at about 70 days when the pile temperatures decreased to near ambient temperature. Losses in total organic carbon and total nitrogen were significantly higher in the turned windrows (treatments TF7 and TF3) than in the static pile (treatment TF0).