Abstract:
Hydroponics system is an easy and environmentally good approach where plants are
grown without the support of soil media. The system is mainly affected by water quality
parameters, especially, dissolved oxygen (DO), pH and temperature. Echinodorus
beleheri was selected for this study because of its fast growth rate and availability. The
objective of this study was to determine the effect of DO concentration on Echinodorus
beleheri in hydroponics. The different DO concentrations were maintained by giving
aeration by pumping at four different time durations such as 10, 20, 30 and 40 min and
DO concentration was measured daily using DO electrode. Simultaneously, a control
experiment was carried out without aeration. Each treatment was used in four
replicates (four tunnels). The rate of growth of Echinodorus beleheri was measured by
counting the number of runners, baby plants and leaves weekly and length and width of
leaf and plant height by non-destructive method at weekly interval. The experiment was carried out in Completely Randomized Design (CRD) and the data were analyzed using
SAS package. The highest DO concentrations were observed in the growth medium
aerated at 30 and 40 min intervals and there was no significant difference (p>0.05)
among these two values. The growth medium aerated at 10 min interval showed lowest
DO concentration. The highest yield as measured by runners, number of baby plants and leaves was observed in the growth medium aerated at 40 min interval. Recommended
DO level of growth medium should be higher than 8 mg/L. Recommended DO level was
obtained in treated tunnels. DO levels were increased and DO reduction was prevented
by the all aeration treatments. Frequent aeration had positive impact on plant
productivity. Plant growth and productivity increased after the continuous pumping
treatment.
