Yield and quality of sugarbeet owning to cultivar and to graduated nitrogen rates

Authors observed the influence of nitrogen fertilization on yield of sugar beet root and also its quality (digestion, extraction of refined sugar, yield of refined sugar, alpha-aminonitrogen) using two cultivars of sugar beet (Renata and Kristall). In order to provide this, a field experiments in years 1997-1998 at warm and moderate dry climatic area of south-western part of the Slovak Republic were established. Experiment had three treatments of fertilization: No - non-fertilized control, N80 - 80 kg of nitrogen, plus 65 kg (1997) or 38 kg phosphorus per hectare (1998), N120 - 120 kg of nitrogen, plus 65 kg (1997) or 38 kg phosphorus per hectare (1998). The content of accessible nutrition by method of electroultrafiltration provided that all fertilization treatment were fertilized to achieve required level. Phosphor fertilizers was applied in simple superphosphat forms, nitrogen fertilizers in nitre ammonium-calciphile form. Kalium and magnesium were not used. The specimens needed to determine the factors of technological quality was taken off along with harvesting of sugar beet. The yield of sugar beet was highest at both cultivars in N80 treatment (90.57 t/ha at Renata, 79.48 t/ha at Kristall). Renata had the highest digestion at N80 fertilization (15.46 degree S), Kristall at N120 treatment (15.80 degree S). As optimal variant from a ration of refined sugar point of view was determined treatment N120 for both examined cultivars (Renata 12.58%, Kristall 13.10%). The highest yield of polarised sugar was recorded at Renata yielding on treatment N120 (11.57 t/ha). The influence of nitrogen fertilization was expressed in content of unhealthy alpha-aminonitrogen at roots. The least values was on treatment N80 at Renata (5.33 mmol/100g), and Kristall at non-fertilized treatment. Based on the results as optimal amount of nitrogen can be recommend the rate of 80 kg N (+65 kg P) per hectare. By using this dose the highest yield of roots (85.03 t/ha) and polarised sugar (12.40 t/ha) of both cultivars in average was achieved. The level of alpha-aminonitrogen was concurrently the least (5.38 mmol/100g). Cultivar Renata occurs as better suitable in present soil-climatic conditions