Lettuce (Lactuca Sativa) Growth Performance in Saltwater, Soil and Aquaponic System

Soil erosion is a major problem in most agricultural field where it threatened the whole ecosystem. Conventional planting included heavy applies of pesticides and fertilizer had given negative impact to the environment. Aquaponics of combining aquaculture and hydroponics in one integrated system is a useful revolutionary food production system. Salinity can inhibit the plant growth but saltwater aquaponics is studied as an extension from aquaponics recently. Lettuce is selected as the study plant species. A study had carried out by comparing the lettuce seeds germination and plants growth in soils and aquaponics, and lettuces growth with and without salt treatment in freshwater and saltwater aquaponics. The result showed no significance difference on seeds germination and plant growth between sandy soil and coconut coir soil (P > 0.05). Lettuces in aquaponics had the highest total water content, mean plant height increment, and most leaves. Germination of lettuce seeds that treated with different salt concentration was inhibited and the one treated with 0.2M salt solution had no germination. Growth of lettuces from saltwater were inhibited whether it was preliminary treated with salt or not whereas those from freshwater grew very well. In conclusion, aquaponics was more effective in growing lettuces than soils. Freshwater is more suitable to use for growing lettuces than saltwater. Saltwater inhibited lettuce growth whether with or without salt treatment. Waste product from aquaculture had successfully utilised as a nutrient source for growing crops.