In plot trials, seeded in a pure stand without a cover crop, tetraploid red clover varieties bred at Jogeva - 'Varte' (early) and 'Ilte' (late), outyielded the diploid standard varieties in crude protein yield at optimal harvest schedule by 30.8% as an average of two production years (the yields 2255 and 1724 kg ha*[-1), respectively) and 14.9% (the yields 2073 and 1804 kg ha*[-1), respectively), by 26.3% as an average of three production years (the yields 2254 and 1785 kg ha*[-1), respectively) and 28.4% (the yields 2173 and 1693 kg ha*[-1), respectively). Considering the crude protein content of dry matter and crude protein yield, a three-cut harvesting regime should be applied in early tetraploid red clover varieties to attain the best result. Then the first cut should be taken at the budding stage, the second at early bloom of regrowth and the third cut prior to the commencement of night frosts. The late tetraploid red clover varieties should be harvested twice-the first cut at the budding stage and the second cut prior to the first night frosts. The larger crude protein yield of tetraploid varieties was caused mainly by their higher dry matter yield; it was affected to a lesser extent by the crude protein content of dry matter. Yet, the tetraploid varieties exceeded in majority of harvest times the diploid varieties in dry matter's crude protein content but the excess was mainly insignificant.

The study deals with the rural landscape management in Latvia and presents a survey of the current situation in landscape planning and nature protection. It also gives a brief theoretical description of the landscape concept and its development and management. Impact of agriculture, forestry and rural tourism on landscape is analysed through the view on the state politics in these spheres. The author evaluates current situation in environmental politics, informs about environmental law, nature protection and preservation system and spatial planning. The author also draws conslusions and offers her suggestions how to improve the landscape management system basing on comparison between the current situation in landscape management and goals set by the national environment conservation plan (1995).

More than 17,5% of Latvian agricultural land is abondoned, therefore effective use of this land is a significant issue in national economics. One of the alternatives of how to use abandoned agricultural land is its afforestation by birch. The present research is based on the Scandinavian experience. Calculations have been made on the necessary investments and management costs. The recovery and possible impact on price changes in raw birch materials are analysed as well.

Problems in hulless barley growing are caused by a low germination ability and emergence. Grain quality for feed and food are influenced by threshability and infection with fungal diseases. The aim of experiments was to investigate the possible hulless barley seed and grain quality problems under Latvia's conditions. Germination, emergence, test weight, 1000 grain weight and threshability of 77 hulless barley genotypes of diverse origin were determined and compared to hulled control varieties. Correlation between hulless barley germination, grain germ damage and grain infection with Fusarium, Helmintosporium and Penicillum was analyzed. The seed material structure (content of grains with damaged germ, broken grains and grains with undetached hulls) of 5 hulless barley genotypes was determined.

A field trial concerning optimisation of a mineral fertiliser (NPK) in the production of perennial ryegrass 'Spidola' seeds was established at the Skriveri Research Centre of the Latvia University of Agriculture in 1999. Experiments were conducted on sod-podzolic sandy loam soil (Luvic Phaeozem, WRB 1994). In 2000, the first seed production year, which was quite unsuitable in terms of climatic conditions, the nitrogen fertiliser showed significant influence on seed and straw yields. The use of phosphorous and potassium fertilisers in all combinations with nitrogen decreased the resistance of the crop to lodging.

The aim of the research was to find out different aspects of food environment at schools, linking them to the economic situation in the regions and comparing those to the tendencies in Riga. The research shows that there is a need for common politics concerning school meals as every schools follows its own practice that mainly depends on social budget of the local government institutions, qualifications of scool personnel and different eating traditions in different regions.

Weather conditions in Latvia are very favourable for the development of potato late blight caused by Phytophthora infestans (Mont) de Bary. The control of potato late blight can be performed using different approaches: standardised technology, prognoses of the first infection and prognoses of the progress of disease development. The negative prognosis model Negfry is based on the last two mentioned above. For the control of potato late blight in Latvia mainly has been used - standardised technology. The first field treatment was made during the row closing or according to prognoses. Regular treatments were made each 8-14 days. The use of NegFry model started in Latvia in 1998. Local varieties and weather data have been used for the trial. For the control of potato late blight in field trials standartised fungicide application was compared with the NegFry model and the untreated variant. The major task of the use of the model is possibility to reduce the number of fungicide treatments. The NegFry model helps to realise an integrated plant protection system, which decreases fungicide application and increases economical efficiency.

The field experiment of IOSDV (set up in Tartu in 1989) with application of mineral nitrogen fertilizer in combination with different forms of organic fertilizer (manure, straw) during 2 years has led to changes in mineral nitrogen level depending on fertilization regime used. Crop rotation was the following: potato-spring-wheat-spring-barley. The weather conditions during the period of the study were rather different and it appeared that weather conditions are more important factors in determining mineral nitrogen content and crop yields than applying fertilizers.

By using city of Jelgava and its separate districts as an example, the article investigates the practical applicability of some theoretic investigations related to the life in cities.

The change from large scale agriculture to private small scale farming has resulted in a severe lack of plant protection means. Fields of Latvia have become more weedy for last four years. This fact shows the necessity for a change in the strategy of weed control. The effect of inexpensive and wide-spread herbicides 2.4-D and MCPA is insignificant in weed control. From 1994 Latvian State Centre of Plant Protection has been studying the occurance of weed species in the Central part of Latvia (Vidzeme), to make use schedules of necessary herbicides. The research was carried out jointly with the Latvia University of Agriculture. During the research carried out from 1997 to 2000, 60 weed species were established, but in all the crop sowings 10 species were predominant. The number of Elymus repens, Myosotis arvensis and Viola arvensis has increased during last four years. In Vidzeme region, from 1997 to 2000, it was stated that soil infestation of weed seeds varies from 4.5 to 11.1 thousand seeds per square metre on the average. Perennial dicot-weeds have shown the lowest variation coefficient, compaered with other weed groups.