THE RELATIONSHIPS BETWEEN MINERAL NITROGEN-CONTENT IN THE SOIL, YIELD AND SUGAR CONTENT IN SUGAR-BEET

In field trials when diffirent nutrition was applied, N(an) content in the soil was determined in different periods of ontogenetic development of sugar beet along with the relationships to the sugar beet root yield of sugar beet and its sugar content. The results experimentally obtained indicated that changed method of nutrition influenced also N(an) contents and their forms in the soil. The most marked differences were recorded, however, under the concrete soil conditions of different experimental plots not only in the total N(an) content but also in its different forms. N(an) content in the soil was observed to be dependent on weather conditions in the growing season. The relationships between inorganic, eventually between nitrate nitrogen in soil and the yield, or between sugar beet content, were different. Nitrate nitrogen content in the soil not even in a single date exhibited the significant dependence on the yield. On the contrary, highly significant negative dependence (r = -0.77 to -0.59) this exerted in the relationship to the sugar content of sugar beet. Inorganic nitrogen in the soil was in the significant to highly significant positive correlation to the yield at the first to third sampling and in highly significant negative correlation to the sugar content of sugar beet at the third to fourth sampling. Regression equations were calculated for the given relationship. Knowledge obtained may be for the given relationships. Knowledge obtained may be applied to predict yields and properties of sugar beet or in purposeful regulation of nutrition of this crop within its monitoring.