Effect of biostimulant application and long-term storage on the nutritional value of carrot

Abstract

ABSTRACT The nutritional value of carrot is determined by the content of total sugars and monosaccharides, carotenoids and vitamins, including vitamin C, in its roots. In 2009-2011, field experiments were carried out concerning the effect of biostimulating preparations applied during the carrot vegetation period on selected nutrients of its roots (total sugars, monosaccharides, carotenoids and vitamin C). Two biostimulants were foliarly applied in doses of 2 or 3 L ha-1 on various dates. Kelpak SL and Asahi SL: one, two or three applications; where, second and third applied at 2-week interval, additionally Kelpak SL: one application at 4-leaf phase, followed by additional application after 4 weeks. The field study was conducted in a randomized block design with four replications. The treatments of plant protection from diseases and pests complied with carrot requirements. The subject of the research was carrot of the Karotan cultivar. The content of selected components in carrot roots was determined directly after harvest and after six months of storage in the storage chamber with controlled temperature and relative air humidity. The foliar application of Kelpak SL in a single dose (2 L ha-1) at 4-leaf development phase resulted in the significant increase of total sugars, reducing sugars, total carotenoids and vitamin C. A six-month storage period resulted in a decrease of total sugars by 5% and ascorbic acid by 16.8% compared to nutritional values measured right after harvest.