Acta Univ. Agric. Silvic. Mendelianae Brun. 2013, 61, 1613-1619
Published online 2013-11-24

The effect of urea with urease inhibitors and urea on yield and nitrate content in potato tubers

Karel Drápal, Miroslav Jůzl, Petr Elzner, Vít Mareček

Department of Crop Science, Breeding and Plant Medicine, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic

The three-year field trial was established on two localities – Žabčice and Valečov in 2010–2012. Seven variants of nitrogen fertilization in four replications have been involved in this experiment – 100% of urea (U), 80% of urea, 60% of urea, 100% of UreaStabil (US), 80% of UreaStabil and 60% of UreaStabil, whilst 100% corresponded to 90 kg N.ha−1 after subtracting the content of Nmin in the soil, and the control variant without fertilization by mineral nitrogen. The two varieties with different lengths of vegetation periods have been chosen for the experiment – the early variety Karin and the mid-early variety Red Anna. In all cases, samples for the yield and qualitative analyses have been taken according to the phenological phase – the beginning of physiological maturity. The obtained results show that the highest average yield has been achieved in the variant of 100% of urea – 40.95 t. ha−1, the yield of this variant was statistically significantly higher than the yield of the other variants of fertilization (P < 0.05). Variants treated by urea without the urease inhibitor reached an average yield of 37.62 t.ha−1. However, this yield was not statistically significantly higher when comparing to the urea with the urease inhibitor (P > 0.05). In regard to localities, a relatively high average yield (44.58 t.ha−1) has been achieved on a characteristically potato-growing locality Valečov. This yield was statistically significantly higher than the one attained on the Žabčice locality (P < 0.05). In respect to varieties, the mid-early variety Red Anna attained a higher average yield (39.65 t. ha−1). Likewise, this yield was statistically significantly higher than the one of the early variety Karin (P < 0.05). The best year was 2012, in which the average yield of 38.73 t.ha−1 was achieved. This yield was statistically significantly higher than the yield of the year 2010 (P < 0.05). As far as nitrates are concerned, the lowest average nitrate content has been found in the control variant – 184.1−1 of moisture content. Nevertheless, the differences of the nitrate content among all the varieties were statistically inconclusive (P > 0.05). When using the fertilizer consisting of urea without the urease inhibitor, a lower average content of nitrates was found – 207.8−1 of moisture content, but there was no statistically significant difference in comparison to the urea with the urease inhibitor variants (P > 0.05). In respect to localities, lower average nitrate content was established on the Žabčice locality – 177 mg.kg1 of moisture content. A statistical significance in comparison to the Valečov locality was found (P < 0.05). The mid-early variety Red Anna had a lower average nitrate content – 167.7−1 of moisture content. When compared to the early variety Karin, a statistical significance was found P<0.05. Two years showed the lowest average content of nitrates – 2011 (181.6−1 of moisture content) and 2010 (188−1 of moisture content). No statistical significance (P > 0.05) was found between 2010 and 2011, but in contrast to the year 2012, a statistical significance in regard to the nitrate content was established (P < 0.05).


22 live references