Impacts of Humic Acid on Growth, Yield, and Quality of Tomato: A Review

Tomato (Solanum lycopersicum) is one of the most adaptable, popular, and widely consumed vegetable crops in the world. However, current production levels of tomatoes fall short of consumer needs. Enhancing soil fertility presents a viable solution to address the issue of low productivity in tomato cultivation. Humic acids (HA) are organic molecules that significantly improve soil characteristics, plant growth, yield, and quality. There was limited information available in previous studies regarding the issue; therefore, the review was conducted to investigate the issue in greater detail. The review aims to consolidate existing knowledge on the topic and encourage further investigation to refine agricultural practices and enhance crop production. In the narrative literature, keywords related to the topic investigated in popular databases over the last three decades were screened for relevant papers, and the information was presented in different sections of the manuscript. The application of humic acid has positively influenced several parameters, including growth, development, yield, and quality of tomatoes. Humic acid increased the stem diameter, number of leaves per plant, and plant height. Additionally, humic acid topically improved fruit weight, fruit diameter, fruit number per plant, and yield. Furthermore, skin color, lycopene content, fruit juice acidity, ascorbic acid, and total soluble solids were all markedly improved by applying humic acid. The information synthesized here may benefit policymakers, agricultural advisors, and experts in the field, supporting the development of effective strategies for sustainable tomato production using humic acid.