The Dynamics of Energy Efficiency of the Grain Crops in Republic Bulgaria
Research Institute for Mechanization and Electrification of the Agriculture, BG-1080 Sofia, Bulgaria
IVANOV, D., 2000. The dynamics of energy efficiency of the grain crops in Republic Bulgaria. Bulg. J. Agric. Sci., 6: 381-385
The dynamics of energy efficiency of principal grain crops in the Republic of Bulgaria for the period 1984 - 1996 has been studied. Basically, four grain crops were involved - wheat, barley, maize for grain and sunflower. The methods applied were comparative and regression analyses of the respective regression coefficients. The tendencies and reasons for the alarmingly low values of energy inputs per area unit as well as the respective energy expenditure levels have been analyzed.
It has been established that the energy efficiency coefficient of grain cereals has achieved its maximum value in the period 1989-1990. The following period of 6 years shows a constant decrease of this coefficient from approximately 1.65 to about 1.21. In maize for grain, there has been a constant decrease of this coefficient from approximately 1.81 at the beginning of the 13-year period to approximately 1.58 at its end. The average annual decrease of the energy efficiency coefficient is about 0.018. The energy efficiency coefficient of sunflower was at its maximum in the period 1989-1990. In the following period up to 1996, this coefficient showed a constant decrease from about 1 to 0.85.
Key words: grain production, coefficients of energy, fertility, mechanized operations, energy inputs, energy expenditures