Earthworm Urine Used as Foliar Spray on Amaranthus hybridus (Green amaranth) Boosts Growth and Stimulates Stomata Opening

Abstract

The advent of spray drones for agrochemical applications calls for continuous exploration of potentially affordable and sustainable liquid biofertilizers. Thus, we evaluated the effects of earthworm urine foliar spray on the growth performance (height, number of leaves, leaf area, stem girth) and stomata opening of Amaranthus hybridus (Green amaranth). Earthworm urine was obtained by placing 500 g of Libyodrilus violaceus in one litre of earthworm saline, for one hour. Amaranthus hybridus seeds were planted into 90 pots, divided into three treatment groups of 30 pots each. Upon germination, the first group was sprayed with earthworm urine, the second and third groups with saline water and ordinary water, respectively. Earthworm urine significantly (p < 0.05) increased all the measured growth parameters, and stimulated the opening of stomata, relative to saline water and ordinary water. This result is a strong indication that earthworm urine contains hormones that boost plant growth, and is potentially suitable for use as a liquid biofertilizer, for increased production of Amaranthus hybridus and related vegetables.