Hüsnü Ünlü

The influence of foliar and soil fertilization of humic acid on yield and quality of pepper

Abstract Humic acid (HA) is the result of organic matter decomposition and is beneficial to plant growth and development. The objective of the study was to find the influence of foliar and soil HA application on fruit quality and yield of organically grown pepper. Pepper plants were treated with soil and foliar HA applications at various concentrations (0 ml/l, 10 ml/l, 20 ml/l, 30 ml/l, and 40 ml/l). Starting four weeks after planting, HA was applied via spraying and/or drenching to the plant root area three times during the growth period at 15-day intervals. HA treatments had no significant effect on fruit firmness, fruit length, or diameter. Total and reducing sugar contents significantly increased in response to both foliar and soil HA treatments. Moreover, HA application significantly influenced total chlorophyll content and this effect was mainly on chlorophyll b content. Foliar 20 ml/l and soil 20 ml/l HA application resulted in the highest total chlorophyll content. Foliar and soil HA applications also led to significantly higher mean fruit weight, and early and total yield than for control. The study demonstrates that both soil and foliar HA treatment might successfully be used to obtain higher fruit yield and can significantly enhance fruit quality in organically grown pepper.