V. MANOLOVA1, S. KOSTADINOVA2 and I. MANOLOV2
1 Fruit Growing Research Institute, BG - 4004 Plovdiv, Bulgaria
2 Agricultural University, BG - 4000 Plovdiv, Bulgaria
MANOLOVA , V., S. KOSTADINOVA and I. MANOLOV, 2014. Economic efficiency of fertilization and its residual-effect during conversion period to organic field crop production. Bulg. J. Agric. Sci., 21: 1022-1026
The transformation of a conventional production system to an organic one passes through the obligatory period of conversion, when the farmers are obliged to apply all restrictions for organic production. Most of the farmers bear losses because of the lower productivity of crops during the period of conversion and the additional expenses necessary to be made (certification of production). At the same time their products are realized at the price of conventional crops. The study was based on a long term field fertilizer experiment conducted by the Department of Agrochemistry and Soil Science at the Agricultural University – Plovdiv. Since 2006, fertilization of crops in the rotation was excluded. The aims of the study were to determine the economic effectiveness of fertilization in conditions of conventional production and the residual-effect of fertilization during the period of conversion to organic production. The following indicators were used: additional yield (kg.ha-1), cost of fertilization (BGN.ha-1), additional income from fertilization (BGN.ha-1), additional profit from fertilization (BGN.ha-1), costeffectiveness of fertilization (%), and residual effect of fertilization - additional profit (BGN.ha-1). The results of the study proved that systematic fertilization before the period of conversion, selection of a suitable rotation and elimination of the expenses for fertilization generate incomes comparable to incomes accumulated from conventional production - from 1507.75 to 4596.97 BGN.ha-1.