Physiological Response of Pea (Pisum sativum L.) Plants to Foliar Application of Biostimulants

The use of biostimulants in crop production can be an economically viable option for farmers and enable them to meet the increasing quality standards of agricultural products and consumer expectations for sustainability and environmental protection. The aim of this study was to determine the effect of foliar application of biostimulants on the course of physiological processes in pea (Pisum sativum L.) plants. Field studies with conventional fertilizers/biostimulants of plant origin (N1) and an ecological biostimulant of animal origin (N2) in the cultivation of eight pea varieties were carried out in the years 2015–2017 in south-eastern Poland. With favorable weather conditions during the flowering and pod setting period, as a result of N1 and N2 fertilization, in the BBCH 65 and BBCH 79 phases, there was a significant increase in the relative Chl content, Chl fluorescence parameters (Fv/Fm, Fv/F0, PI) and gas exchange (Pn, E, gs), measured in pea bracts. The relative content of Chl and the course of physiological processes in the plant were more favorably affected by N1 fertilization. Our data also confirm the beneficial effect of N2 application, but weaker than N1, which was determined by the strong negative reaction of plants to N2 fertilization in 2016, with rainfall shortages in the flowering and pod development phases. The experiment showed that in favorable weather conditions the applied foliar preparations have a positive effect on the physiological processes occurring in the plant, but in drought conditions they do not significantly mitigate its negative effects.