Growth, yield and nitrate accumulation in fruits of cucumber fertilized with sources of nitrogen fertilizers

Abstract

There is a lack of information about sources of nitrogen fertilizers in cucumber crop. Although essential to obtain high productivity N source, in certain species, can promote accumulation of nitrate in the edible portions, which, reduced to nitrite, is a risk factor for health. The study aimed to evaluate the effect of four sources of N on plant growth, concentration and fluorescence of chlorophyll and the production and accumulation of nitrate in cucumber fruits. The experiment was conducted in a greenhouse, in pots 10 L filled with soil. The N sources were: 1 - ammonium sulfate (100% ammonia); 2 - ammonium nitrate (50% and 50% ammonium : nitrate); 3 - sodium nitrate (100% nitric) and 4 - urea (100% amide). For all N sources, we used the dose of 160 mg N kg-1 soil. This dose of N was applied installments weekly for eight weeks, beginning one week after transplanting. There was no significant difference between N sources to all traits. All sources had the same efficiency in the production of fruit and low nitrate accumulation in fruits (0.193 mg kg-1 fresh weight). We conclude that, for cucumber culture, the producer must use the power of nitrogen fertilizer due to a lower cost per kg of N, in this case, urea.