Date-Palm Compost as Soilless Substrate Improves Plant Growth, Photosynthesis, Yield and Phytochemical Quality of Greenhouse Melon (<i>Cucumis melo</i> L.)

Abstract

The selection of adequate substrate for soilless culture is based on technical and economic considerations. Therefore, the search for alternatives by the valorization of natural by-products is gaining importance. The main objective of this study was to compare the effects of local farm resources, date-palm waste, as culture substrate, to coconut fiber (CF) (commonly used in soilless culture) on melon (Cucumis melo L.) plant growth, water relations, photosynthesis, chlorophyll fluorescence as well as phytochemical analysis under hydroponics culture system. Two growing substrates were tested: the compost of date palm waste added to animal manure (7:3 w w−1) (DPAM) and the date palm trunk compost (DPT). Coconut fiber and soil were used as positive and negative controls, respectively, in randomized blocks. Results showed that the vegetative growth was improved under DPT and CF substrates while CF substrate enhanced fruit yield and phytochemical properties: Total soluble solids TSS (% Brix), total dissolved solutes (TDS); Titratable acidity (as citric acid); Sugar content and juice pH of melon fruit. Date-palm waste-based substrates enhanced the vegetative growth and the fruit yield of melon as compared to soil-based culture. It seems that date palm waste-based substrates, especially trunk compost, could be promising and cheaper alternatives compared to coconut fiber substrates commonly used in Tunisia in soilless cultures.

Keywords

• date-palm compost
• soilless cultures
• melon fruit
• photosynthesis
• chlorophyll fluorescence
• phytochemical analysis