Can Biofilm Biofertilizer Cut Down Chemical Fertilizers in Leafy VegetablCultivation? A Case Study with Centella asiatica (Gotukola)

Abstract

Purpose: In Sri Lanka, an excessive usage of chemical fertilizers (CF) has been observed in agriculture which affects negatively for health and wellbeing of consumers as well as environment. Biofilm biofertilizer (BFBF) is a novel technology which is being practiced in many crops to enhance the productivity while improving soil quality. However, the BFBF has not been applied for leafy vegetables thus far. This study was conducted to introduce BFBF to C. asiatica (Gotukola) cultivation as a case study, in order to reduce the usage of CF. Research Method: Firstly, a field experiment was carried out to evaluate the minimum CF rate that would not hamper the yield of C. asiatica cultivation. Then, different combinations of reduced rates of the minimum CF level and BFBF (Biofilm-veg™) were applied with a control of no amendments, and yield was recorded to explore the possibility of CF reduction with the BFBF application. One-way ANOVA, Tukey’s HSD test, and cost-benefit analysis were used to compare the treatments. Findings: The study revealed that even with only 60% of the farmers’ CF rate, there was no observable yield compromise. Thus, the optimum CF requirement for the crop was identified as 60% of the farmers’ current CF rate. By coupling of BFBF the amount of CF could be brought further down to 48% of farmers’ current CF rate. Furthermore, the application of 48%CF+BFBF produced a plant growth comparable to that with 100% CF. Research Limitations: There were some practical limitations such as long dry spells and also findinsuitable fields for the experiment, due to farmers’ hesitation on possible yield reduction. Originality/ Value: Application of BFBF is an effective method to cut down CF by half in C. asiatica cultivation, thus minimizing the adverse effects of CF. Several studies have been conducted thus far to analyze the possibility of biofertilization in cutting down CF in agriculture, but they have only been limited to inoculation of isolated soil microbial mixtures. Present study is the first attempt to evaluate the capability of developed microbial biofilm-based BFBF application in reducing CF use in leafy vegetable cultivation.