Аңдатпа
In an experiment with the use of a stable isotope of nitrogen 15 N, the impact of fertilizers on grain yield of spring wheat and spring triticale on the dark chestnut soil in the dry steppe zone of Northern Kazakhstan was estimated. The maximum yield of spring wheat grain was obtained when introducing N 60 before sowing and that of spring triticale (2.2 times higher) when introducing N 60 in equal parts before sowing and during tillering. The effect of nitrogen fertilizer on yield of both the crops is more efficient compared to phosphate fertilizers. Both the crops used 30% of the introduced doses of fertilizer nitrogen for yield formation; 32% was fixed in the soil under spring wheat, 34% under spring triticale, and gaseous losses of nitrogen fertilizer were 38% and 36%, respectively. The maximum use of nitrogen fertilizer on yield formation (41–42%) is typical of both the crops when introducing N 30 before sowing both against the background with and without phosphorus. As a result of better nitrogen use by plants, its gaseous losses fell to 15–26%. It is noted that, both in case of P 0 and P 60 , levels of fertilizer nitrogen use decreased almost twofold, from 41–42 to 23–28%, when the nitrogen fertilizer dose was doubled. Fractional introduction of N 60 by equal parts before sowing and during tillering hardly affected the amount of nitrogen fertilizer used by plants of both the crops for yield formation. The use of N 30 during tillering compared to a similar dose before sowing reduced the factor of fertilizer use by plants.