Smart farming development for growing Asiatic pennywort in an organic system to reduce contaminants and increase the yield of important substances

Abstract

The research titled “Smart farming development for growing Asiatic pennywort in an organic system to reduce contaminants and increase the yield of important substances” aimed to study a smart farm system that can control environmental conditions inside a greenhouse to be suitable for the synthesis of bioactive compounds in each cultivar of Asiatic pennywort under an organic farming system free from contamination. The research was carried out in two main activities as follows: 1) The design and development of a smart farm control system in the greenhouse using an embedded computer programmed with Arduino to control the equipment. Asiatic pennywort was cultivated in a double-roof greenhouse measuring 4 × 12 meters. The experimental results showed that the smart farm control system, which regulated relative humidity in the air, greenhouse temperature through a misting system, and soil moisture through a mini-sprinkler irrigation system, was able to maintain the environmental conditions inside the greenhouse at appropriate levels. This resulted in good growth of Asiatic pennywort in all seasons. 2) The study of the effects of different Asiatic pennywort cultivars grown under an organic farming system in a smart greenhouse free from contaminants. The experiment was designed as a Split Plot in a Completely Randomized Design (CRD) with three replications. The main factor was Asiatic pennywort cultivars, namely Nakhon Pathom, Ubon Ratchathani, and Rayong. The sub-factor was fertilizer management consisting of
(1) fertilizer application following farmers’ recommendations, and (2) application of biochar compost at a rate of 1,000 kilograms per rai. Cultivation was conducted in each season, and data were recorded on the morphology of each cultivar, heavy metal content in leaves, quantity of bioactive compounds, and asiaticoside content. The results showed that the Ubon Ratchathani cultivar produced the highest yield, while the Rayong cultivar produced the lowest yield per area. When analyzing the heavy metal content in the leaves of all cultivars grown with both chemical and organic fertilizers, it was found that the levels were lower than the general standard values specified in the Thai Herbal Pharmacopoeia (Volume 1, 1998–2000). The Rayong cultivar grown in all seasons contained the highest amounts of bioactive compounds. During the summer, it showed the highest total phenolic content, total flavonoid content, and antioxidant activity by the DPPH method—10.59 mg GAE/g DW, 105.38 mg GAE/g DW, and 4.48, respectively. The asiaticoside content was found to be the highest in the Rayong cultivar grown during the rainy season at 34.48 percent. Cultivation using biochar compost made from durian husks at a rate of 1,000 kilograms per rai resulted in the greatest production of bioactive compounds.