Characterization of soil treated and optimization studies on AB mix nutrients usage towards capsicum frutescens

This thesis investigates the characterization of soil treated with AB mix nutrients and the optimization of its usage towards Capsicum frutescens (C. frutescens) cultivation. Driven by the need to address the environmental issues arising from excessive fertilizer usage that exceeds recommended guidelines, this study aims to determine optimal nutrient application rates that are environmentally sustainable while maintaining agricultural productivity. Employing characterization techniques such as Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES), EnergyDispersive X-Ray Fluorescence (EDXRF) and Vector Network Analysis (VNA), the research identifies elemental composition and evaluates soil dielectric properties. EDXRF analysis revealed significant detection of elements spectrum in the soil at different energy ranges; the several elements detected were aluminium (Al), sulphur (S) and chlorine (Cl), where the element intensities observed vary with the electrical conductivity (EC) levels of AB mix nutrient. This analysis provided detailed elemental composition of the soil, revealing notable increases in elements such as aluminium (Al), which was detected at 2227.105 cps/mA at the lowest EC value, 1.4 mS/cm to 3031.773 cps/mA at 3.5 mS/cm. The highest dielectric constant, ε’ of the soil sample was observed at 1.4 mS/cm with 6 mL of AB mix nutrients, with the value of 2.2 mS/cm, whilst the lowest dielectric constant, ε’ was recorded by the controlled sample with ~1.1208. As for the VNA measurements, results showed that higher applications of nutrients generally resulted in lower S-parameter values (S11 and S21), reflecting changes in the soil’s electromagnetic properties due to varying nutrient concentrations. As the X-band frequency increased, the real and imaginary parts of S-parameters demonstrated distinct trends. The real S11 (reflection coefficient) and S21 (transmission coefficient) typically decreased with the increasing frequency, f indicating reduction in signal reflection and transmission efficiency as the nutrient concentration increased. Conversely, the imaginary parts of S-parameters showed variations that suggest complex interactions between the electromagnetic waves and the soil’s physical properties, reflecting changes in the soil’s dielectric constant, ε’. For further understanding on AB mix nutrients concentration effect towards the C. frutescens growth, Response Surface Methodology software (RSM) was employed. Result showed that the optimal conditions of the AB mix nutrients for C. frutescens were recorded at the concentration of 2.54 mS/cm of AB mix nutrients and the wick length of 18.15 cm. Under these conditions, the maximum plant’s height simulated using Analysis of Variance (ANOVA) and RSM was 38.73 cm, which was comparable with the experimental result that recorded 40.2 cm as the maximum height. In short, this research provides an understanding of AB mix nutrient properties, the interaction of nutrients on soil with the microwave frequency, f and the optimum condition of C. frutescens growth using fertigation Nutri-pot system. These findings highlight the importance of good fertilizer practices that adapt to specific soil characteristics, promoting sustainable agriculture by optimizing fertilizer use, thereby reducing environmental impact and supporting effective crop growth.