G. PANAYOTOVA1 and Sv. KOSTADINOVA2
1 Trakia University, Faculty of Agriculture, Student Campus, BG - 6000 Stara Zagora, Bulgaria
2 Agricultural University, Faculty of Agronomy, BG - 4000 Plovdiv, Bulgaria
PANAYOTOVA, G. and Sv. KOSTADINOVA, 2015. Nitrogen fertilization of durum wheat varieties. Bulg. J. Agric. Sci., 21: 599–604
The response of durum wheat to nitrogen (0; 80; 120 and 160 kg N.ha-1) was studied in a long-term fertilizing experiment in crops rotation cotton – durum wheat for the period 1998 – 2010 in Institute of field crops – Chirpan, Bulgaria. The experimental design consisted of split-plots design with four replications. Assessment of durum wheat response to nitrogen was studied by means of main nitrogen use efficiency indicators Partial factor productivity (PFP) and Agronomic efficiency (AE). It was found that durum wheat varieties positively responded to nitrogen fertilization. Average of thirteen years, relative grain yield increased with 25-29% at a rate of N80; by 40-43% at a moderate rate of N120, and by 45-46% at the rate N160. The yield variation was highest at no fertilized control for both varieties. Throughout the thirteen years period PFP for nitrogen changed in the range from 15.6 to 77.1 kg.kg-1 and depended on the yield level, respectively on the climate conditions. Variety Progress showed higher PFP at N80 compared to variety Vazhod and the difference was 11.2 kg.kg-1. AE for nitrogen varied from 0 to 26.7 kg.kg-1. In average, AE slightly changed in dependence of nitrogen rate and variety and was in the range 9.6-12 kg.kg-1.