Abstract:
An experiment was conducted to assess the performance of automatic pH and Eco monitoring and control system for hydroponically grown lettuce (Lactuca sativa), with the objective of creating a precisely controlled nutrient environment with minimum labour cost for achieving high yield. The experiment had two treatments with four replicates arranged in a complete randomized design. Desired nutrition and pH levels in the automatic system were maintained precisely at set levels throughout the experiment, while the adjustment of Ec and pH of the control experiment was done manually. Daily air and solution temperature, relative humidity and light intensity in the protected house were measured. Comparison of dry andf resh weight of the yield and subsequent root weights between two treatments were measured 24 days after transplanting. Plant growth in both treatments was virtually identical and resulted in an average shootf resh mass o f165.97g in the automatic system and 156.94 g in manual control system. However, the difference was not significant at alpha level 0.05. The automatic system had the ability to correct pH and Eco levels instantly just after deviation from the set levels. The results revealed that performance of the automatic system satisfies the requirements to grow lettuce in NFT system and could be recommended as a suitable system for Ec and pH adjustment in hydroponically grown crops
