Abstract:
This study was conducted as six months of research experiment to evaluate the
effectiveness of biogas slurry foliar application combined with inorganic fertilizers and
suggest suitable rate of biogas slurry dilution in pot culture for optimum growth and
yield of red onion crop (Allium cepa L). Biogas slurry, a nutrient-rich by-product from
anaerobic digestion, is an eco-friendly and cost-effective organic fertilizer with
potential to improve crop growth when used as a foliar spray. The experiment was laid
out using complete randomized method (CRD) with four different treatments and five
replicates. The treatments are Tr with recommended fertllizer (control treatment), Tz -
1 :1, T:- 1 :2 andT+ - 1 :3 (slurry: water on the volume basis).Except the control treatment
113 of recommended fertilizers were applied to the other treatments. Biogas slurry
diluted solution was applied as foliar treatments at two weeks intervals with the amount
of 75ml per pot (0.03m2) from the 2nd week of planting at two weeks of interval for
three times. The growth parameters such as plant height and number of leaves were
measured at one week interval from the 2"d week of planting, yield parameters such as
number of bulbs, diameter of the bulbs, fresh and dry weight of the plants and yield per
area (kglm2) were measured at the time of harvestin g. Data were analyzed by Analysis
o1'Variance. Pair comparisons among treatments means were tested at 5o/o significance
ievel by Tukey's studentized range test by using minitab software.
The results indicated that foliar application of biogas slurry combined with inorganic
fertilizers had a positive effect on red onion growth and yield performance. Especially
in the T+ concentration than the other treatments, this treatment significantly enhanced
plant height up to 52.14+2.79, leaf number up to 8.60+0.24, and bulb's diameter up to
2.70+A.05.The findings suggest that biogas slurry can serve as an effective organic
foliar fertilizer combined with inorganic fertilizer, contributing to improved growth and
potentially higher yield in red onion cultivation.
