Ефективност на минералното торене на царевица за зърно, отглеждана на Излужена Смолница в Югоизточна България в години с благоприятни и рискови метеорологични условия

摘要

This investigation was aimed at determining the effect of mineral fertilization on corn for grain, cultivated without irrigation and in years with favorable and risky climate conditions. A 50-year longterm stationary fertilizer trial in Pellic Vertisol (FAO) was analyzed. The effect of the fertilization on the realization of the biological potential of two biotypes com hybrids was determined in years with sufficient rainfall and water deficit (drought). The economical levels have been calculated, in which the hybrids realize stable long term gains. N-P-K fertilization norms were determined along with soil content with mineral nitrogen, mobile potassium and phosphorus, which reduce the risk of com cultivation on Pellic Vertisol in Southeastern Bulgaria without irrigation.