Deployment of Sawdust as Substrate Medium in Hydroponically Grown Lettuce |
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| Authors: | Marirena Christoulaki Sofia Gouma Thrassyvoulos Manios |
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| Institution: | 1. Department of Plant Science, School of Agricultural Technology, Technological Educational Institute of Crete, Heraklion, Greece;2. Department of Organic Greenhouse Crops and Floriculture, School of Agricultural Technology, Technological Educational Institute of Crete, Heraklion, Greece |
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| Abstract: | In this study, lettuce plants were grown in sawdust (Saw) and/or perlite (Per) mixtures (sawdust; Saw:Per 75:25%; Saw:Per 50:50%; Saw:Per 25:75%; Perlite) and in Nutrient Film Technique (NFT), in an unheated greenhouse. Plants grown in NFT were taller with greater leaf area resulting in greater fresh weight. Sawdust addition reduced leaf length, leaf area and as a consequence the fresh weight but not the leaf number. However, leaf dry weight increased as sawdust content increased into the substrate. Leaf chlorophyll reduced but leaf fluoresces increased in perlite and NFT. High sawdust content (75% or 100%) reduced photosynthetic rates and stomatal conductance. Nutrient uptake potassium (K), sodium (Na), phosphorus (P)] was the greatest in NFT treatment, while perlite and Saw:Per 25:75% increased elemental uptake (up to 74%) comparing with the remaining treatments. Leaf elemental analysis fluctuated among treatments. Thus, low content (i.e. 25%) of sawdust in perlite could improve inorganic substrate media properties. |
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| Keywords: | Lactuca sativa sawdust NFT organic materials perlite plant growth soilless culture lettuce yield |
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