Sugar beet root yield in relation to selected growing and climatic conditions

This paper presents three-year field trial results orientated on the influence of selected factors (nutrition, sowing distance, variety, soil type, climatic conditions) on sugar beet root yield. Polyfactorial field trials were realised in Milhostov on a FluviûEutric Gleysol (very heavy clay soil) and in Vysoka nad Uhom on an Eutric fluvisol (middle heavy soil). Both localities are situated in the central part of the EastûSlovakian Lowland, which can be characterised as very warm and dry to very dry climatic region. There were used conventional soil techniques with applications of manure (beside variant V5 in field trial A) and ground limestone (6 t/ha). The forecrop was winter wheat. A variation of relation of sugar beet root yield and different agroclimatic factors was provided of two parallel field trials. There were observed five different nutrition variants (V1 û V5) and three variants of sowing distances in the rows (16û18û20 cm) in the field trial A and this influence on the sugar beet root yield. The Adonis variety was used. Nutrition variants: V1 û nutrition correction during vegetative period on the basis of easy hydrolysing nitrogen in soil, V2 û nutrition correction during vegetative period on the basis of inorganic plant analysis, V3 û content of available nitrogen in soil completed on the dose of planned sugar beet root yield (40 t/ha), V4 û doses of nutrients stated on the basis of the EUF (electro-ultrafiltration) method, V5 û control non-fertilized variant. Nitrogen doses were calculated on the basis of available nitrogen balance in the soil (to a depth of 600 mm). The doses of phosphorus and potassium were calculated for the planned sugar beet root yield (40 t/ha). In field trial B there was followed the root yield of nine sugar beet varieties at a constant nutrition level (corresponding with the V4 variant in the trial A) and the equal sowing distance in the rows 18 cm apart. Five varieties were resistant towards the rhizomania (varieties: Adela, Monriz, Flair, Ibiza, Formula) and other were proved to be sensitive (varieties: Intera, Olympus, Adonis, Kredo). Over the threeûyear field trial average sugar beet root yield was found to be 64.26 t/ha in trial A and 68.70 t/ha in trial B. Statistical analysis confirmed the evident influence of nutrition on the variability of sugar û beetroot yield in trial A. Nutrition was the source of 85.07% yield variability. Soil type had a stronger influence on the yield than sowing distance in the rows. The meteorological conditions as an individual factor had statistically lower influence on the yield in comparison with their interaction with soil type. The participation of other interactions was relatively low despite statistical significance. In trial B there was ascertained an evident influence of soil type on the sugar beet root yield for the followed varieties. The individual variety was registered as the fourth factor in order of factors. In this case the influence of meteorological conditions was more important. On the other hand, meteorological conditions as individual factor had stronger influence than their interaction with soil type.