Caractérisation physique des substrats de croissance pour une meilleure adaptation à la filière horticole en Tunisie

Peat is the most used growth substrate in modern horticultural nurseries. However, this material is very expensive and continues to pose problems in matter of supply. That's why, research projects were conducted to partially or completely substitute this material using other natural sources and agricultural waste locally available at lower cost. The overall objective is to develop a growth substrate by achieving suitable mixtures of peat with Co-compost (usually obtained from the composting of lignocelluloses biomass mixed with fermentable biomass) or compost (resulted from the composting of a single biomass, balanced in content of carbon and nitrogen), and evaluating their physical properties (total porosity, aeration porosity and retention porosity). The gradual substitution of peat with increasing percentages (25, 50 and 75 %) of Co-compost or compost significantly affects total porosity, aeration porosity and retention porosity of the resulting growth substrate. Results show that certain mixtures containing peat and Co-compost meets standards in term of porosities; however, those standards are not complied in term of the aeration porosity for the two following proportions: (50 % peat + 50 % Co-compost) and (25 % peat + 75 % Co-compost). If the incorporation of Co-compost with peat is not interesting beyond 25 %, the partial substitution of peat with 50 % screened forestry compost revealed encouraging results. [PUBLICATION ABSTRACT]