Yield and chemical content of carrot storage roots depending on foliar fertilization with magnesium and duration of storage

Yield amount, maturity stage, morphological as well as biological properties of carrot roots are cultivar-dependent. In 2007-2009, field experiments involving foliar fertilization of carrot with magnesium sulphate (acrid salts) on yield and selected yield constituents (dry matter, monosaccharides and total sugars) of carrot storage roots were conducted. Magnesium was applied in doses of 0, 45 and 90 kg MgO ha –1 in the form of 3% sprays during the intensive growth of carrot. The tested carrot belonged to five cultivars: medium-late Berjo and late Flacoro, Karotan, Koral and Perfekcja, all characterized by good shelf life. The yields of carrot storage roots depended on a cultivar and foliar fertilization with magnesium. The cultivar Flacoro gave the highest yield of 60.82 t ha –1 and cv. Karotan – lowest (51.40 t ha –1 ). The application of foliar magnesium fertilization during cultivation in the doses of 45 and 90 kg MgO ha –1 caused a significant increase of root yield of about 4.2 and 8.7%, respectively. The content of dry matter, reducing sugars and total sugars was determined in carrot roots immediately after harvest and after six months of storage. Regardless of the experimental factors, storage roots of cv. Karotan contained the highest amount of dry matter (138.7 g kg –1 ), reducing sugars (25.2 g kg –1 ) and of total sugars (76.8 g kg –1 ) based on fresh matter. Increasing fertilization with magnesium led to a significant increase in the content of all the analyzed constituents in carrot storage roots. The most successful was the dose of 45 kg MgO ha –1 , which caused the highest significant increment in dry matter, reducing and total sugars.