The effect of different fertilisers and storage temperature on the content of reducing sugar in potatoes of different varieties, destined for processing into chips, was investigated at the Elmininkai Research Station of the Lithuanian Institute of Agriculture during the period 2000-2001. Five potato varieties belonging to different maturity groups were investigated: early 'Goda' and 'Voke', medium early 'Lady Rosetta', medium late 'Saturna' and 'Hermes'. Potatoes of all the investigated varieties were grown in the plots with different fertilisation: 1 - manure - 40 t ha*[-1), 2 - chopped straw+one-component mineral fertilisers at the rate of N45P45K90, 3 - one-component mineral fertilisers at the rate of N90P90K180, 4 - complex mineral fertilisers with microelements at the rate of N90P90K180. It was established that reducing sugar content in potato tubers depended on the genetic properties of the variety, storage temperature and fertilisation.

Balance of nitrogen, phosphor and potassium content in four rotations of sugar beets (in respective periods of 1965-1973; 1974-1982; 1083-1991 and 1992-2000) was established at the Rumokai Research Station of the Agricultural Institute of Lithuania. Extended crop rotation of nine fields included two fields of winter wheat or rye (22.2%), two fields of sugar beets (22.2%), two fields of barley (22.2%), one field of perennial grass, i.e. red clover and meadow timothy of the first year use (11.1%), one field of perennial grass - red clover and meadow timothy - of the second year use (11.1%) and one field contained vegetated fallow with the drilled mixture of vetch and oat for green fodder (11.1%). Organic-mineral fertilisation system was employed in the process of crop rotation.

During the period of 2000 and 2001, field trials were established with the aim to evaluate the productivity and forage quality of lucerne. The most productive lucerne varieties were 'Birute', 'Radius' and 'Belorusskaya' yielding 13.5-14.6 t ha*[-1) DM, during the years of sward use. The most content of crude protein 170-175 g kg*[-1) have been obtains from 'Karly', 'Radius' and 'ABT-205'. The highest digestibility was observed in the developing line No 60. Acclimatization of rhizobia within lucerne roots has been determined applying streptomycin resistant forms. In field conditions acclimatization within lucerne was more successful by strains 05 (40-100%).