Integration of nanobubble-driven drip fertigation and soil conditioner in enhancing some of soil chemical–biological responses, chili growth, yield and quality

Nanobubble-driven drip fertigation and soil conditioners are increasingly applied to enhance red chili productivity, a key Indonesian cash crop with high economic value but limited export competitiveness. This integration improves water and nutrient delivery, increases dissolved oxygen, and enhances soil properties, thereby supporting better growth, yield, and quality. This study aims to examine the synergy of nanobubble-driven drip fertigation and soil conditioners in enhancing soil chemical–biological properties, as well as the growth, yield, and quality of red chili. The experiment used a strip-plot design with two factors, namely nutrient source (NPK, drip fertigation, and drip fertigation + nanobubble) and type of soil conditioner (manure, bioameliorant, and ameliorant), each with three replications. Observed parameters included pH, organic carbon, total nitrogen, available phosphorus, phosphate -solubilizing bacteria (PSB) and nitrogen-fixing bacteria (NFB), growth, yield, and fruit quality. The results showed a significant interaction between nutrients and soil conditioner on PSB populations, P availability, fruit number, fruit weight per plant, and fruit quality. The drip fertigation + nanobubble treatment increased fruit weight by 299.18 g/plant (39.77%) and fruit number by 59.25 g/plant (34.1%) compared to the NPK and manure treatment. The PSB population, plant height, and stem diameter positively contributed to fruit weight, while stem diameter, plant height, and chlorophyll content were positively related to fruit number. Furthermore, increasing soil pH correlated with an increase in the proportion of fruit quality categories A and B. Overall, the pH and organic carbon variables directly influenced the increase in good fruit quality (A+B) by 39.5%.