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.

It is very important to use the exact investment model for energy enterprises. Giant investment is necessary for establishing continued energy systems using renewable energy resources. Demand of the heat energy usually is higher in a winter period compare to the summer time. Program combinations of different heating modus are researched using EnergyPRO.

The effect of different fertilizer backgrounds on the potato yield and its chemical composition of different varieties, destined for processing into chips, was investigated at the Elmininkai Research Station of the Lithuanian Institute of Agriculture in 2000. The investigation showed, that potato tuber yield depended on fertilization and genetic characteristics of the potato variety. The most productive potatoes of the following varieties were: early Voke (20,6-36,0) t ha*[-1) and medium late Saturna (27,0-35,4 t ha*[-1)).

The content of reducing sugars can be 30% higher if modified amylase is added to scald. Investigations were carried out with the rye-flour and fine flour scald. Photometrical method was used as a standard method for the determination of reducing sugars. Enzymes were inactvated using the advanced method. Results show, that the amount of reducing sugars is 1.8% lower in rye-flour and 2.1% lower in fine flour compare to the results obtained using the standard method.

Milk quality analyses were carried out at the Department of Veterinary Medicine of the LUA Research Centre "Sigra". The total amount of investigated samples was 140, of which 81.4% proved to be appropriate for extra and first class milk, but 18.6% were unqualitative. The total number of microorganisms ranged from 8000 to 20,000,000, but the number of somatic cells from 1000 to 4,068,000 in 1 ml of milk. Coagulase - positive Staphylococcus aureus were isolated in 8 cases or 5.7%. Coagulase - negative Staphylococcus were isolated in 31 cases or 22.1%. Using the BBL Crystal Indentification System for Gram-Positive microorganisms, four species of microorganisms Staphylococcus aureus, Staphylococcus intermedius, Micrococcus sedentarius and Micrococcus luteus were identified which are building various colonies on Baird-Parker Agar.

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).

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.

The article deals with the regeneration process of water resources capacity of the wells in the Baltezers region using mechanical and chemical treatment. The methods of this treatment process are described in detail.

To investigate flood and hydraulic parameters of the river, the hydraulic models of the river Daugava near Jekabpils have been built at the Rural Engineering Faculty of the Latvia University of Agriculture and at the Research Scientific Institute of Water Managmenet and Land. Several possible solutions have bee proposed as a results of these investigations, though only the most effective and economically acceptable variant should be selected.