2016 年 7 巻 1 号 p. 44-49
Nitrogen (N) fertilizers play an important role to increase grain yield and grain quality in crop production systems. In Western Siberia, predominantly used N-fertilizers for cereal production are urea and ammonium-nitrate (‘Selitra’). Due to semi-arid climate, only one fertilizer application is common, simultaneously with sowing and directly into the seed furrow. A new kind of slow-release fertilizer is a modified urea with silicate coating and urease inhibitor and was developed at the State Agrarian University of the Northern Transurals (Russian Federation). In a field trial, the comparative performance of the novel fertilizer type was tested with spring wheat near the city of Ishim in Tyumen region (Western Siberia) on 3.4 ha under on-farm conditions. 4 levels of the slow-release urea (25/50/75/100%) were compared to 100% of conventional urea, 100% of Selitra and an unfertilized control in randomized complete block design with 4 replications. Results showed significant differences in soil nitrate availability but no differences in ammonium release. Differences between N-levels dispersed during heading, afterwards only plots with Selitra fertilization showed significant higher nitrate values. Leaf chlorophyll content as indicator for plant Nitrogen supply showed significant differences from beginning stem elongation on. The harvested grain yield showed no significant differences between the compared fertilizer types at the 100% N-level. Even if the grain yield with reduced dose of slow-release fertilizer was on the same level, it was not significantly higher than the unfertilized control. From the results of this field trial there seems to be no beneficial advantage of the tested slow-release fertilizer so far.
