The influence of fertilization and environment on some nutritionally important quality criteria in vegetables - a review of research in the Nordic countries

To understand the phenomena caused by nutrient applications on the quality of vegetables, some research has been done in Finland and in Scandinavia during the last decades. Purpose of this review is to evaluate this data against the information available on genetic and environmental factors. Genotype and light intensity highly affect the vitamin C content of plants. Optimal nitrogen level has a small effect, but excess of nitrogen decreases vitamin C content. Genotype, developmental stage of the plant, adequate photosynthesis, vigorous growth and relatively high temperature increase the carotene content of carrots. The effects of fertilization on the carotene content of plants have been contradictory and warrants more research. No research results could be found of the effects of fertilization or growing practices on the vitamin B content even though vegetables are an important source of vitamin B in diets. Increasing nitrogen fertilization, genotype, low light intensity, low temperature and drought increase the nitrate content of vegetables, but the levels are low in vegetables grown in the Nordic countries, except in lettuce grown under glass with the aid of lights during the dark season. The effect of fertilization on the sugar content is small, and the effect on dietary fibre warrants further study