Growth and yield of green-leaf Romain lettuce (Lactuca sativa L.) produced in vertical aeroponic system with root zone cooling
Abstract
The growth and yield of green-leaf Romaine lettuce grown under a tropical greenhouse using the vertical aeroponic system with rootzone cooling were evaluated in this study. The experiment was set up using a Combined Analysis in Strip-Plot design in a 6m x 12m greenhouse wherein the two rootzone cooling methods, a ground heat exchanger (GHE) and improvised chiller, were the treatments while harvest periods of 20, 25, and 30 days after transplanting (DAT) were the horizontal factors, and the levels of the tower (top, middle and bottom) were the vertical factors. The IRRI-Statistical Tool for Agricultural Research (STAR) was used for data analysis. Results revealed that longer and broader leaves and higher yield were observed using the improvised chiller and were harvested from the top of the tower at 30DAT. In terms of growth, the best combination of factors was from those harvested from the top of the tower that used an improvised chiller and harvested at 30 DAT. The yield at 30 DAT using an improvised chiller was significantly higher at 78.6 grams compared to using GHE with only 60.5 grams. The economics of using GHE and improvised chiller in green-leaf Romaine lettuce production harvested at 30 DAT in a small area of 18 m2 was found comparably feasible and viable. The former, however, showed better economic indicators with a potential annual net income of Php 64,156.40, ROI of 42% with a payback period of 2.41 years.
