Potato Tuber Yield and Plant Morphological Descriptors as Affected by Nitrogen Application

Nitrogen (N) applied as a unique and relatively high rate can increase soil salinity and lead to potato yield loss. Thus, the aim of this work was to determine the effect of N fertilizer application mode on potato tuber yield and on morphological descriptors of shoot and subterranean organs throughout the potato plant cycle of the cultivars Agata and Asterix. Three treatments were evaluated: T0 (without N), T1 (50% of the N rate at planting time + 50% of N at 22 days after the plant emergency), and T2 (single N rate at planting). The N rate was 220 kg/ha, as urea. Two experiments were simultaneously installed in the field, each corresponding to each cultivar. Applying urea at an inadequate time leads to a 4.3% decrease in crop profitability. For Agata, it is more appropriate splitting urea application and for Asterix it is better not to split the N application. Compared to the unfertilized control, for both cultivars, a suitable mode of N application provided an increase in stem and leaf dry weight and a decrease in stoloniferous root dry weight. Regardless of cultivars, the highest value of dry weight was observed in the tuber, followed by leaf, stem, roots, and stolon.