Growth and development of Alfalfa depending on the type of nitrogen nutrition

Abstract

Mineral and symbiotrophic types of nitrogen nutrition of plants were compared in experiments with the blue-hybrid alfalfa. Variants with seed inoculation by high-mountain strains of nodule bacteria (In-1800 and N30+In) had the maximum height of plants during all experimental years (40-70 cm), which is explained by the better nitrogen provision of plants. At the same time, the effect of the mineral forms of nitrogen appeared only in the year of sowing at the beginning of the growing season to the first mowing, in the future the differences between these options were neutralized. The foliage intensity of plants was in the range of 41.4-54.8%, increasing due to the improved availability of biologically bound nitrogen in plants. Mineral forms of nitrogen reduced plants’ foliage coverage in all experimental years, however, this decrease was noted only in the initial periods of vegetation. The maximum indicators of foliage coverage were noted in the In-1800 variant. By the end of the third year of crops use, the plant stand density was 980-1100 thousand units/ha, and the total thinning of alfalfa crops reached 45-51%. At the same time, the symbiotrophic type of nitrogen nutrition made it possible to significantly increase the competitiveness of plants, which ultimately affected the persistence of the crop density.