Purpose/ The aim of this study was to investigate the influence of two decomposition processes namely, composting and vermicomposting on the chemical composition of the finished products of a mixture of cotton residues:soil and cotton residues: farmyard: soil .Design/ Composting experiments were done over six months to prepare four different mixtures as follows: cotton residues + soil (C), cotton residues +soil+ earthworms (C+E), cotton residues + soil+ farmyard manure (C+F) and cotton residues + soil+ farmyard manure +earthworms (C+F+E). Electrical conductivity, pH, , nitrate-N, ammonium-N, ash, total phosphorus, total nitrogen, total organic carbon, carbon: nitrogen ratio, total potassium and trace elements (Mn, Fe, Cu and Zn) were determined on monthly based samples . Findings/ Significant differences (p<0.05) in organic carbon, nitrate-N, nitrogen, phosphorus, and potassium content were recorded in vermicompost compared to compost. In general, results indicated that vermicompost had a significant effect compared to compost and a positive effect on the chemical properties of the finished products.Originality/ value-This research work was carried out by four researcher from two institution concerning with agriculture production and environment. The paper emphasizes on production of organic fertilizer from agricultural waste to increase productivity and to reduce environmental pollution

The effort were made to study the effect of organic fertilization (compost and vermicompost) produced from cotton residues and farmyard manure as well as to compare between the effects of organic fertilizer in comparison with inorganic fertilizers on Teff grass (Eragrostis tef Zucc.Trotter) as a test crop. Design: Two pot experiments were conducted using Teff grass for two seasons, during 2008-2009; the effect of the four organic fertilizers was compared to that chemical fertilizer and control. The treatments were: cotton residues (CR), cotton residues + earthworms (CR+E), cotton residues +farmyard manure (CR+FYM), cotton residues + farmyard manure + earthworms (CR+FYM+E), urea and Control (C) each treatments in two levels equivalent 1N (1N = 43 kg N/ha) and 2N (2N= 86 kg N /ha). In conclusion , results indicated that the highest values of plant height (84.02, 45.94) , leaves Number (6.44,8.44) and fresh weight (2.13, 1.75) were determined in CR+FYM+E equivalent 2N treatment during the two season. Findings: Vermicompost had a significant effect compared to others treatments and a positive effect of the organic fertilizer application was clearly observed in the second season.