The Effect of Amendment of Vegetable Waste Compost Used as Substrate in Soilless Culture on Yield and Quality of Melon Crops

One of the main environmental impacts of forced systems in horticulture — such as plastic covered and soilless culture — is the generation of organic plant residues and substrate waste. Many people are keen on research and development of ecologically friendly substrates. Thus, leaching experiments have been carried out with distilled water to determine whether compost — from horticultural greenhouse crop waste — can be used as growing media in vegetable crop production. The compost was examined and compared to other substrate alternatives like coconut coir waste. Two experiments were conducted in order to compare the two composts with coconut coir waste in terms of yield and fruit quality of melon crops (Cucumis melo). Electrical conductivity decreased sharply with leaching and eventually reached acceptable levels despite the high initial value of this parameter in the composts. This drop in electrical conductivity was parallel to that experienced in the contents of soluble mineral elements, with mainly high levels in SO4²⁻, K⁺, Cl⁻, Mg²⁺, Ca²⁺ and Na⁺- concentrations. Most of the soluble mineral elements in compost were removed applying six times the amount of water. The comparison between two environmentally sound substrates, show that compost seems to be an acceptable ecological growing medium and similar to commercial coconut coir in soilless culture, it does not affect yield and quality of melon crops.