Effectiveness of nitrogen utilization in winter wheat spring fertilization (Triticum aestivum, L.) | Efektívnosť využitia dusíka pri jarnom hnojení pšenice letnej formy ozimnej (Triticum aestivum, L.)
2010
Vidovič, J. | Slamka, P., Slovenská poľnohospodárska univ. v Nitre (Slovak Republic). Fakulta agrobiológie a potravinových zdrojov, Katedra agrochémie a výživy rastlín | Golisová, A.
In years 1998-2000 three-year small-plot experiment with winter wheat (variety of Astella) and 6 treatments of spring nitrogen dressing was established. Winter wheat was grown after 3 various forecrops: grain pea, maize for silage and spring barley. Experiment was arranged by block method in four replications. Pre-seeding rate of nitrogen, phosphorus and potassium was determined on the basis of soil analyses. In spring winter wheat was dressing in one-shot by constant rates of nitrogen in treatments N35PK, N70PK, N105PK and NuoPK in growth stage of tillering (DC-21). In treatment Nopt (optimized dressing based on Nmin soil analyses) the total N rate was subdivided to three partial rates applied in growth stage of tillering (DC-21), shooting (DC-31) and swelling of sheath of flag leaf (DC-43), respectively. Yield of grain was influenced by experimental year. While in the 1st experimental year the highest grain yield was achieved at treatments fertilized by higher constant N rates (NuoPK or N105PK) in the 2nd experimental year the highest grain yield was gained in optimized treatment (NoptPK). Harvest index of nitrogen (HIN) was decreasing with increasing rate of nitrogen and optimized N rate increased the value of HIN to 0.726. In comparison to unfertilized control increment of nitrogen accumulated by plant (ANp) ascended with increasing spring dressing rate of nitrogen achieving value of 65.8 kg/ha (N140PK) in comparison to 50.2 kg/ha under NoptPK. Efficiency of nitrogen uptake (EPNH) from spring mineral fertilization was decreasing with increasing nitrogen rate with an exception of divided N rate NOptPK treatment which caused a rise of EPNH value even in comparison with the lowest one-shot N rate in treatment N35PK. Optimized-split (NoptPK) in comparison with one-shot spring nitrogen dressing increased physiological efficency (FENzr) by plant better nitrogen utilization for grain yield formation. This was valid for winter wheat grown after grain pea (values was 15.7) and maize for silage (27.4). When spring barley was used as a forecrop the highest value of FENZr (27.0) was recorded at one-shot N dressing N35PK at DC-21.
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