Plant response to biowaste soluble hydrolysates in hibiscus grown under limiting nutrient availability

ABSTRACTBiostimulants are substances promoting plant growth, quality and stress resistance. The present work aimed to investigate whether soluble hydrolysates from biowaste performed as biostimulants. Hibiscus (Hibiscus moscheutos L. subsp. palustris) plants were subjected to four treatments: standard fertilization, low fertilization (LF), and LF with added soluble digestate or soluble compost. Plant performance indicators were biomass accumulation, biometric parameters, leaf gaseous exchanges and elemental composition, and nitrogen (N)-use efficiency. LF negatively affected most of the investigated parameters. However, plants treated with biowaste-derived products performed better than untreated low-fertilized plants (+21 to 145% for biomass accumulation and biometric parameters, and carbon assimilation rate) and for many parameters reached values comparable to those showed by standard-fertilized plants or even higher, as in the case of Potassium (K), Silicon (Si), and Molybdenum (Mo) leaf content, and N...