Published in Scientific Papers. Series A. Agronomy, Vol. LXVII, Issue 1
Written by Nedyalka YORDANOVA, Nikolay MINEV, Svetla KOSTADINOVA

Agronomic efficiency and Partial factor productivity of N were studied in wheat and barley grown in a long-term fertilizer trial and fertilization systems: Control, N₃₀₀P₄₀₀K₆₀₀+18 t vetch-oat mixture/ha, N₆₀₀P₄₀₀K₆₀₀ (stock fertilization), N₉₀₀P₄₀₀K₆₀₀, N₆₀₀P₄₀₀K₆₀₀+30 t manure/ha, N₆₀₀P₄₀₀K₆₀₀+4 t straw/ha, N₆₀₀P₄₀₀K₆₀₀ (annual fertilization) (І-ІV crop rotations); Control, N₃₀₀P₃₀₀K₄₀₀, N₆₀₀P₃₀₀K₄₀₀, N₉₀₀P₃₀₀K₄₀₀, N₆₀₀P₃₀₀K₄₀₀+40 t manure/ha, N₆₀₀P₀K₄₀₀, N₆₀₀P₃₀₀K₀ (V-VII rotations); Control, N₂₅₀P₃₀₀K₂₀₀, N₅₀₀P₃₀₀K₂₀₀, N₇₅₀P₃₀₀K₂₀₀, N₂₅₀P₁₅₀K₀+60 t manure/ha, N₅₀₀P₀K₂₀₀, N₅₀₀P₃₀₀K₀ (VIII rotation). The studied rates were N₆₀, N₁₂₀, N₁₈₀ (wheat) and N₄₀, N₈₀, N₁₂₀ (barley). A high efficiency of N₆₀ and N₄₀ was found when N was incorporated into organo-mineral fertilization systems. Appling of 18 t vetch-oat mixture∙ha or 60 t manure∙ha increased Agronomic Efficiency of N (AE-N) and Partial Factor Productivity of N (PFP-N) to 54.5-71.3 and 81.8-112.8, respectively. The prolonged exclusion of phosphorus fertilization in the crop rotation strongly decreased AE-N and PFP-N up to 0.7-13.7.

[Read full article] [Citation]

SPUPOPUPNO1