Energetic evaluation of alfalfa growing in various systems of soil preparation and differentiated nutrition

Energy analysis of alfalfa production produced by three different soil preparation systems (BEO - non-tilled system, RED - reduced system and KON - conventional system) was done under three different nutrition intensity (V1 - intensive variant, fertilization for planed yield 15 t/had.m., V2 - reduced variant, for planed yield 12t/ha d.m., V3 - non-fertilized control) for the period of the years 1996-1998. Variants of soil cultivation: Elementary and seed-bed soil preparation was made by agricultural machinery and tools, which application is current in practice, single method of soil cultivation were different. BEO - non-tillage system. In autumn total herbicide Roundup Bioaktiv (prod. fi Monsanto) in the rate 3 l/ha was applied on the emerged summer-weeds after taking of post-harvest forecrop residua. In spring non-tillage seeding machine Great Plains sowed alfalfa depth 20-25 mm and soil was rolled by meadow rolls. RED-reduced system. In spring, after taking of post-harvest forecrop residues, the soil was prepared by solo operation - with tillage rotary machine Mars (prod. firm Hlohovec) Slovak Republic, to depth 60-80 mm. Alfalfa was sowed by seeding machine Accord (prod. firm Hlohovec) and soil was rolled by meadow rolls. KON - conventional system. In autumn after taking of post-harvest forecrop residues, ploughing was made to depth 220-240 mm and soil cover was prepared by heavy field harrow. In spring the soil was prepared by middle-heavy field harrow, alfalfa was sowed by seeding machine Accord (prod. firm, Hlohovec) to depth 20-25 mm and finally soil was rolled by meadow rolls. The alfalfa polyfactorial trial was conducted on a experimental research base in the central part of East Slovakian Lowland with continental character of climate. The analysis was performed by the balance method based on comparison of total energy input with energy value which was obtained by the yields. The lowest level of energy inputs (14.310 GJ/ha) was found on non-tilled and non-fertilized alfalfa stand, and on that same variant was found also the lowest output value (509.796 GJ/ha). The values of the reached energy outputs increased at both soil cultivation (650.152 - 617.812 - 598.584 GJ/ha according to KON - RED - BEO systems) and nutrition intensities (692.252 - 643.096 - 132.200 GJ/ha in variants order V1 - V2 - V3). The output values followed the (23.319 - 22.524 - 20.960 GJ/ha according to preparation systems and 26.076 - 25.169 - 15.558 GJ/ha according to nutrition variants V1 - V2 - V3). Further energy characteristics (energy profit, energy efficiency and energy input utilisation rationality) are situated in tables and figures. The major part of energy inputs variable values concerning the energy structure is the fossil energy - fertilizers and pesticides. The operations connected with reseeding (ploughing, soil preparation, seeding, direct drilling, cultivation, harvesting) has just a lower partake in energy structure. In regard to concrete soil and climatic conditions were recommended to utilise both followed factors (soil preparation and fertilization) different intensity level and their optimal combination using