YONKO STAMENOV; NELI VALEVA
University of Forestry, Faculty of Agronomy, BG-1756 Sofi a, Bulgaria
Stamenov, Y. and N. Valeva, 2017. Phosphorus and potassium removal assessment in omitted plot trials with wheat and barley. Bulg. J. Agric. Sci., 23 (4): 604–608
“Best agricultural practices for sustainable crop nutrition in Bulgaria” was the topic of an extensive research project supported by International Plant Nutrition Institute (IPNI) during the period 2009-2012. Omission plot trials (control, N, P, K, NP, NK, PK, NPK) were arranged in fi eld, vegetable, fruit crops and wine grapes. Wheat (variety Aglika) and barley (variety Aheloy) were tested in crop rotation on four locations. The paper presents the P and K removal data under two representative for the tested crops conditions of South Bulgaria – Pomorie (Burgas region) and Sadievo (Stara Zagora region). P-removal was more infl uenced by the factor fertilization and for both wheat and barley was lower under conditions of balanced nutrition (NPK) – 6.0 – 7.0 kg.t-1 depending on the site. These lower rates were due to the higher yields obtained under balanced fertilization. K-removal was less infl uenced by the factor fertilization. Its value was lower for Sadievo – 15.0 kg.t-1 for both crops and higher for Pomorie – 17.5 kg.t-1 for wheat and 22.3 kg.t-1 for barley. The differences occurred in the K-removal values were due to the different level of the exchangeable potassium in the soil. In general both P and K-removal were more infl uenced by the site specifi city and the climate conditions of the year than the nutrition regime.