Valorization of Oasis Wastes by Composting Procedure under Hot Arid Conditions of Algerian Saharan Regions

Abstract

The present work aims to follow the evolution of physicochemical and microbiological parameters of compost prepared from a mixture of Poultry Droppings and wastes of some plants under hyper-arid conditions. Composing test was conducted in a completely randomized design experiment in the region of Ouargla located in the south of Algeria (northern Sahara Desert). Three mixtures were prepared, in pits of 1m³ volume for each mixture. Each pit is composed by mixture of poultry droppings and plant residues in amount of 40 and 60% (percentages are proportions by weight), respectively: C1: Poultry Droppings+Phragmites residues (P.D+P.R), C2: Poultry Droppings + Olive Wastes (P.D+O.W), C3: Poultry Droppings+Date palm residues (P.D+D.P). Before and after composting process, temperature, physicochemical parameters (pH, electrical conductivity, organic matter, organic carbon and total nitrogen), and microbial parameters (Enterobacteriaceae, Staphylococci, Salmonella, and Yeasts) were analysis. The results obtained after 90 days of composting process showed a difference in behavior between the three mixtures. In fact, the highest temperature was recorded by the C2 at the thermophilic phase with a temperature of 60°C. A notable decrease in the rate of organic matter, organic carbon and C/N ratio was recorded at the end of the test, especially for the C2.Meanwhile, the electrical conductivity recorded an increase for all the treatments, in particularly for the C1. Microbial analyses show a remarkable decrease in pathogenic germs at the end of the experiment for all mixtures. The three components produced did not show any inhibitory effect on the germination of lettuce seeds. The germination index (GI) exceeds 85% for all treatments. In light of these results it can be concluded that the composts obtained have the characteristics of a stable hygienic product and suitable for use in sustainable agriculture in hot arid conditions.