The effect of urea fertilizer in comparison with the broiler litter on the growth and produced gel of Aloe vera

Aloe vera is considered as one of the most important and economical medicinal plants in various countries of the world as well as Iran. Due to extensive utilization of medicinal plants in the world and also environmental problems associated with the use of chemical inputs, organic resources have increasingly attracted many researchers as better fertilizers to address plant nutrients' requirements. Thus, the main objective of this study was to investigate the effect of broiler litter compared to chemical fertilizers on the growth and gel production of Aloe vera.

This research was carried out at the greenhouse conditions and to do that, a randomized complete block design with four replications was implemented. The experiments consisted of four levels of nitrogen (50, 100, 150 and 200 kg N ha-1) in the form of broiler litter, four levels of nitrogen (50, 100, 150 and 200 kg N ha-1) in the form of chemical fertilizer and also the control treatment (without fertilizer). The studied traits were plant height, the number of leaf per plant, leaf length, leaf width, leaf thickness, total leaf weight, chlorophyll a, chlorophyll b, carotenoids, gel percentage, gel weight and gel viscosity.

The results revealed that the plant height, the number of leaf per plant, leaf length, leaf width, leaf thickness, and leaf weight in the broiler litter treatment were significantly higher than these traits in the control treatment. In more detail, the highest plant height (42.62 cm) was obtained in 100 mg kg-1; while, the highest leaf length (29.57 cm) and the highest leaf width (5.85 cm) were achieved in 200 mg kg-1. Moreover, the highest leaf thickness (1.37 cm) was identified in 100 mg kg-1 and the maximum leaf weight (1190 g) belonged to 150 mg kg-1 in which they were all in the form of broiler litter. On average, the broiler litter was able to produce 4.8% more leaf than the chemical fertilizer. Among various treatments, the highest gel percentage and weight were obtained in 100 and 150 mg kg-1 of the broiler litter, respectively. Also, the highest chlorophyll a and chlorophyll b were observed at 200 mg kg-1 in the broiler litter and chemical fertilizer forms, respectively. On average, the broiler litter increased carotenoids up to 2.15 percent more than chemical fertilizers. Eventually, the viscosity of the broiler litter treatments was considerably lower than chemical fertilizer.

It is generally concluded that the broiler litter more remarkably enhances the leaf and gel weight and better improves the quality of Aloe vera gel in comparison with chemical fertilizer. Therefore, the application of broiler litter is highly recommended in order to achieve optimal leaf and gel production of Aloe vera in the greenhouse conditions.