Effects of Chelidonium majus and Ascophyllum nodosum Extracts on Growth and Photosynthesis of Soybean

Herbal extracts used in agriculture are formulated from plants (or other organisms) as alternatives to synthetic chemicals that could have adverse effects on growers, consumers, or the environment. In this study, the effects of two herbal extracts on soybean were assessed: Chelidonium majus (C7: Celext 07) and Ascophyllum nodosum (ST: Stimulagro). A standardized approach for germinating seeds and monitoring early seedling growth for 15 days (SOP-Soybean) was used to evaluate the effects of these extracts. Growth characteristics, chlorophyll content, and photosynthetic rate were measured on the fifteenth day after sowing (DAS). A combination of C. majus and A. nodosum (C7+ST), both 1 g L-1, was the most beneficial treatment and significantly increased shoot height (13.2%), dry mass (10.7%), and photosynthetic rate (20.3%). In a separate experiment, foliar application of the same compounds was performed on the tenth and twentieth DAS, with sampling on the thirtieth DAS. Foliar applications with 1 g L-1 of A. nodosum (ST) significantly enhanced the dry mass (23.5%), and the photosynthetic rate was increased even at 10 days after application (22.5%). Therefore, seedling exposure to C. majus (C7) and A. nodosum (ST) and foliar applications of A. nodosum (ST) stimulated the growth and development of soybean. These natural compounds seem to have the potential to act as growth stimulants for soybean and should be tested for their capacity to improve field growth and yield.