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Contents
hydrological aspects of Flooding of the nemunas river deltaRomanas ASCILA, Antanas DUMBRAUSKAS, Petras PUNYSSummaryDelta of the river Nemunas is mainly suffering from floods in Lithuania. Despite a relatively low urbanization of this area there exist enough infrastructures good enough for the development of agriculture, therefore flood damage affects people as well as farms. The right bank of the river is not protected from floods, except the largest settlements. Even small spring floods inundate this area each year (return period 1.05-1.2 year). The network of gauging stations is dense enough to describe the hydrologic regime of the Nemunas delta. Continuous observations of stage and discharge have one of the longest series in Europe (since 1812). Despite many research works carried out previously in the region of the Nemunas delta there still remains an important object for studies of flood phenomena. Fast development of new technologies enables to look at the problem deeper and get more precise results. The main task of this paper is the estimation of the main hydrological characteristics of spring floods in inundated areas. As a result of a long time data analysis it was found out that severity of floods has a tendency to be decreased. There is a slight negative trend of peak discharge during all the period of observations and their evident decrease since 1960 that continues until now. Having compared several probability distributions, the Pearson Type III has been selected to give the best results to the extreme values of stages and discharges. Discharge-duration-probability curves evidently and clearly describe the main flood characteristics. The flood mapping procedures have been performed coupling GIS technologies and a one-dimensional hydraulic model. Digital maps of flooded areas for different return periods are recommended for floodplain planning and management as well as for the development of flood insurance system. Keywords: peak stage and discharge, time series distribution, probability, flood mapping.
Article given 01 2002, given to print 04 2002.
NITROGEN CONCENTRATION IN OPEN WATERCOURSES AS A RESULT OF LEACHING FROM AGRICULTURAL FIELDSGinutis KUTRA, Ramute AKSOMAITIENE, Ausra RACKAUSKAITESummaryDifferences in soil-climatic conditions, land use and farming activity complicates the application and validation of universal models to predict the pollution of water bodies with nitrogen. A relationship between nitrogen content in rivers and its determining factors should be established independently for every region with homogeneous agro-climatic conditions. From 1996 to 2001 we were making the measurements of nitrogen concentration in subsurface drainage water, open G-1 ditch and the Graisupis river, that are typical for most intensive agricultural region in Lithuania. Average concentrations of mineral nitrogen in subsurface drainage water from different crop fields were calculated and student’s t-test was performed in order to find out if average values have the reliable difference. Regression-correlation analysis was carried out trying to reveal the relationship among nitrogen concentration in open watercourses, subsurface drainage water, crop type and fertilization. The highest average concentration was found in drainage water from fields under row crops – 15 and 11.6 mg l-1 in G-1 and Graisupis watersheds. A little bit lower concentration was observed in the drainage water from fields under spring and winter cereal crops: accordingly 11.4-11.6 in G-1 watershed and 10.7-10.8 mg l-1 in the Graisupis watershed. Probability of error in rejecting the hypothesis that nitrogen concentration from fields under grass is equal to nitrogen concentration from other crop fields is very small (0.02-0.08%). High probability of error (77 and 90%) suggests that there is no significant difference between average concentrations in the drainage water from spring and winter cereals and in that from row crops and legumes. Disperse analysis using monthly nitrogen concentrations showed that the concentration in G-1 ditch can be calculated by the linear regression equation y=1.13x-2.47, where x is average monthly nitrogen concentrations in drainage water and R2 is 0.77. Monthly nitrogen concentration measured independently in G-1 ditch is in some correlation with the concentration in the Graisupis river (regression equation – y = 0.75x+0.54, R2=0.59). Relationship among nitrogen concentration in subsurface drainage water (y), fertilization (x1) and the area of perennial grass in a watershed (x2) can be expressed by the following equation: y = 0.029x1 - 0.051x2 +10.129. Using the established relationships, nitrogen concentration in open watercourses in the Central part of Lithuania can be predicted when the fertilization and area of grass in a watershed are known. Keywords: nitrogen concentration, correlation, subsurface drainage, open watercourse.
Article received 01 2002, given to print 04 2002.
WETLANDS PRESERVATION AND PROTECTION IN LITHUANIA Diana LATSANOVSKY, Juozapas VYCIUS Summary Lithuania has relatively large wetland resources. According to Ramsar Convention definition, wetlands include the following ecosystems: quagmires, bogs, marshes, fens, swamps, sloughs, shallow lakes, rivers and creeks, brooks, areas of seashore, man-made reservoirs and ponds, etc. In this way about 7-10 % of country’s territory can be qualified as wetlands. These ecosystems are particularly important as habitats for some species of flora and fauna. Besides, in the future wetlands may serve as attractive tourist objects for local and foreign visitors, because many years ago these ecosystems were destroyed and converted into agricultural or industrial areas in most Western European and other developed countries. Our studies carried out in 1998-2000 showed that inhabitants do not understand clearly the importance of wetlands attributing them only to the eighth place from nine our proposed to qualify ecosystems. Most inhabitants ranked ecosystems according to their importance in the following order: forest, river, lake, arable land, reservoir/pond, meadow, pasture, wetland, flooded meadow. That is why factors influencing the possibilities of wetland preservation and protection were studied further in the presented paper. There were examined people’s attitudes towards the importance of wetland preservation and protection, possible wetland protection mechanism, people’s knowledge of existing legislation on wetland status, main obstacles for wetland preservation, inhabitants willingness to pay for wetland protection. Finally, the conclusion results of our study were presented in the paper together with the data obtained by other scientists working on the wetland preservation problem in other countries. Although there are some differences between the results of our study and the research data of other scientists, in all surveyed countries including Lithuania the role of wetlands is considered as most important when maintaining biological diversity, and future generations are considered to be the biggest stimulus to preserve wetlands and to pay for their preservation. This shows some people’s awareness, their desire to save all forms of living beings for the future. Keywords: wetland protection, protection mechanism, wetland laws.
Article received 01 2002, given to print 04 2002.
INSTITUTIONAL CHANGES IN THE BRANCH OF UKRAINE. WATER MANAGEMENT: PROBLEMS AND PROSPECTSLeonid KOZUSKO, Vitalij OKORSKIJ, Ruslan KOSTIUKEVICSummaryThis article gives the comprehensive analysis of major problems of the branch of Ukraine water management and states the reasons of their emergence. The structuralisation of problems is being carried out and reasons of the slow progress of the reform in water management field are being considered. Authors discuss strong and weak points of the branch and suggest alternative variants for the restructuring of water management the fulfillment of which depends on strategic priorities of the institutional level of field management and on favorable environment. Keywords: water management, structure, reformation, investment, mechanism of the management, engineering firm.
Article received 01 2002, given to print 04 2002.
INFLUENCE OF ORGANIC SAPROPEL ON THE PRODUCTIVITY OF CROPS AND SOIL CHARACTERISTICSEugenija bakSienESummaryThe investigations on the effects of organic sapropel were carried out in soddy-podzolic sandy loam soil in Voke Branch of the Lithuanian Institute of Agriculture in 1994–1999. Results of the investigations confirm that fertilization of soil with various rates of organic sapropel and its mixtures with manure and urine influences the productivity of crop rotation. The mixture of 10 t/ha of sapropel plus 25 t/ha of manure was more effective and reliably increased the yield by 22 and 25 %. The effect of manure was the same as the effects of smaller sapropel rate and sapropel-manure mixture. Application of organic sapropel for the fertilization of soddy-podzolic soil on the background without mineral fertilizers did not change the soil reaction – pH remained almost the same, while on the background with mineral fertilizers the soil was fertilized with various rates and mixtures of sapropel and its reaction changed from close neutral (pH – 6.6) to slightly acid (pH – 5.7). The amounts of total nitrogen and humus just slightly depended upon fertilization. The amounts of phosphorus and potassium increased only after the fertilization of soil with minimal rates of mineral NPK fertilizers. To compare with the effect of manure, the application of organic sapropel improved the indicators of soil moisture, soil bulk density and total porosity. Keywords: sapropel, manure, yield, soil, properties.
Article received 01 2002, given to print 04 2002.
The research on the deterioration of reinforced concrete structures functioning in the ZONE OF alternative WATER levelKazys Aleksandras VaiSvila, Leonas LindiSas, Raimondas SadzeviCiusSummary16 functioning water engineering constructions (WEC) in various regions of Lithuania were selected for the investigations. The selected WEC are located in Alytus, Anyksciai, Kaunas, Kedainiai, Marijampole, Pakruojis, Raseiniai and Siauliai districts. The principal reinforced concrete structures of the mentioned WEC - spillways and retaining walls in the alternative level of water were investigated. The objective of the study was to establish actual values of compression strength of concrete used in structures, the depth of gully on the surface of structures, actual functioning period of structures and their interrelationship. Actual functioning period of the oldest WEC is 46 years, the one of the newest WEC is 8 years. The structures made of weak concrete were damaged much more. The average deepening speed of a gully in the structures with 27.59 MPa compression strength of concrete was about 0.18 mm per year, the one in the structures with 5.76 Mpa compression strength of concrete was 8.01 mm – 8.31 mm per year. The equations of average deepening speed of a gully with average compression strength of concrete and functioning period of a 30 mm thick covering layer of a structure were developed. The research data presented in the article refers to the improvement when designing new structures or repairing the damaged ones in time. Key words: compression strength of concrete deterioration, functioning period of structures.
Article received 01 2002, given to print 04 2002.
INVESTIGATIONS OF NITROGEN, PHOSPHORUS AND POTASSIUM BALANCE IN THE SOILS OF KARST ZONEAurelija RUDZIANSKAITESummaryThe paper presents calculations of balance of the main plant nutrients (nitrogen, phosphorus and potassium) for crop rotation in moraine sandy loam soils of karst zone. It has been established that surplus nitrogen balance is observed when the soil is fertilized with the following rates: N60 for potatoes, N100 for barley (no nitrogen is applied when perennial grass is cultivated). Surplus phosphorus balance occurs when all plants are fertilized with P30 rate. Surplus potassium balance is observed when applied potassium rates are as follows: K120 for potatoes and perennial grass, and K60 for barley. The least surplus or deficient balance of plant nutrient results in the increase of plants nutrient leaching. Under the conditions of the most deficient balance the leached amounts of nitrogen, phosphorus and potassium were 24, 0.1 and 3 kg/ha respectively; when the balance was least deficient the leached amounts of these elements were 4, 0.2 and 5 kg/ha respectively. Keywords: nitrogen, phosphorus, potassium, balance, leaching.
Dr. Aurelija Rudzianskaite, research worker of Hydroreclamation laboratory at the Lithuanian Institute of Water Management. Main tendencies of scientific researches – environmental engineering and local studies, the researches of drainage and ground water regime and pollution. Address: Parko 6, Vilainiai 5048 Kedainiai district, Lithuania Tel. +370 347 6 80 08. E-mail: aurelija@water.omnitel.net. Article received 01 2002, given to print 04 2002.
THE LENGTH OF LABORATORY CHANNELS NECESSARY FOR THE STABILIZATION OF SUSPENSION FLOWAlfonsas RIMKUS, Saulius VAIKASASSummaryThe analysis results of recently published data revealed that the initial channel strip necessary for the stabilization of hydraulic characteristics and sediment distribution in the suspension flow must be much longer than that in the case of clear water. It was assumed generally that it is sufficient to have this strip as long as the one used for clear water. Thus, the measurements were done in a non-stabilized flow. Consequently, the analysis of received experimental data became complicated. The stabilization of sediment distribution in suspension flow occurs later because of the peculiarities of large main whirlpools, which strongly influence the vertical sediment distribution in turbulent flow and, like clouds, accept the sediments injected into initial strip of experimental channels. These peculiarities are discussed in this paper. The successful analysis of measurement data can be performed investigating the action and parameters of these whirlpools. The data of already fulfilled measurements, i.e., the available chronograms of turbulent velocities and sediment concentration fluctuations can be applied for it. This would help to understand better the mechanism of interaction between sediments and turbulent flow. As a result, more perfect investigation and calculation methods of these processes could be developed. Keywords: suspended sediments, turbulence vortices, hydraulic investigations.
Article received 01 2002, given to print 04 2002.
THE INFLUENCE OF SIZE AND CONFIGURATION OF LAND PLOTS ON RATIONAL LAND USE FORMATIONLaimonas LANKELISSummaryLand management projects of the land reform include the reorganization of land use of agricultural enterprises, with other plots of land situated alongside them. The problems of land redistribution are solved in a complex way, considering the interests of all users. Private and state land uses are being formed. A particular attention is focused on their size and configuration while planning land plots. Three cadastre vicinities of Jurbarkas region in Taurage district have been chosen as investigation objects. Investigation data has been collected with the help of land management specialists from local authorities and the authors of land management projects of the land reform. The analysis of the size and configuration of private plots of land has been carried out. Coefficients applied to production standards have been determined as well. Factors having influenced the land use formation have been evaluated. The perspectives of formed land use areas as well as the possibilities for the formation of rational-sized land use areas have been evaluated. Keywords: land plot size, configuration, land use, agricultural land.
Article received 01 2002, given to print 04 2002.
ECONOMICAL GROUNDING OF STAND PLANTING IN AREAS LESS FAVOURABLE FOR FARMINGDaiva MATONIENESummaryLithuania’s orientation to European Union changes essentially the attitude to the land use, farming types, environmental protection. Particularly many reforms are planned in areas less favourable for farming. In April 9, 1998, the Government of our republic carried the resolution No 425 “About enactment of the order of stand planting in private land” (Lietuvos..., 1998). The main stand planting directions, which are based on economical aspect – fixed point of land efficiency - as well as on rational farming land, are foreseen in this order. Having carried out this investigation it was established that the profit from marketable agricultural plants (wheat, rye, triticale, oat, barley, buckwheat and potatoes) is gained in farms where farming land profit reaches 32.0 and more points of efficiency. So, it can be maintained that such farming land profitability point can be treated as a limit between productive and less productive lands. Stand plants could be grown in farming land with 32 points of productivity, without changing the purpose of land use. Above mentioned Government’s resolution No 425 “About enactment of the order of stand planting in private land” should be corrected. According to expert opinion, normative profitability up to 8%, when there is average intensity of the activity and good farm management, already allows us to fulfill farm reproduction and could be treated as a limit between low and average productivity of farming lands (Caplikas ir kt., 1999). So, in accordance with this and having carried out correlation – regressive analysis between gained profit in the farms from 1 ha and productivity point of farming land, it was established that this limit works when farming land productivity is 35.0 points. Keywords: less favourable areas for farming, agricultural land, stand planting.
Article received 01 2002, given to print 04 2002.
THE ANALYSES OF THE USE OF ARABLE LAND IN LITHUANIAN FARMS IN 2000-2001Vilma SUDONIENESummaryThe structure of the crops of agricultural enterprises and farms, grown in 2000 as well as declared in 2002 has been analyzed. In figures presented one can see: declared crop areas in districts, declared land plots according to ownership forms, grain, flax, sugar-beet, rape and potato crop areas declared and grown in Lithuania, the main agricultural plant crop areas. Farming land and crop declaration is at the same time the declaration of plant-growing producer for the gaining of state support. Farmers, agricultural enterprises and other users wishing to get subsidies or any other state support should make a requisite declaration. Keywords: declarations, crop, plants, land.
Article received 01 2002, given to print 04 2002.
REMOVAL of ORGANIC MATTER DURING GROUNDWATER TREATMENT USING powdered natural adsorbents (zeolites)Marina VALENTUKEVICIENESummaryAn experimental modelling method was developed to measure the capacity of powdered natural adsorbents (zeolites) to adsorb organic matter (extract of peat). The investigation was carried out on a pilot plant consisting of adsorber- mixer models into which aerated groundwater was supplied. In addition to adsorption by natural powdered zeolites from Ukraine “Zakarpatnerudprom” company, different concentrations of organic matter were tested in drinking water treatment facility. Ingredients of used zeolite are as follows: 55- 85% of clinoptilolite, 15-20% monthmorilonits and 10% of quarc. Chemical formula of clinoptilolit is Na(AlSi5O12)*6H2O. Zeolite is mechanically resistible under the pressure of 20 MPa and thermal resistible below 7000C. Chemical ingredients include: SiO2-77.9%, TiO2-0.18%, CaO-2.10%, MnO-0.17%, Fe2O5-1.05%, Al2O3-13.04%, K2O+Na2O-5.24%. Used powdered adsorbent (<0.5-mm particle size) indicated the influence of organic matter concentrations and pH range on natural zeolites. The effect of pH on the adsorption capacity of adsorbents was evaluated. It was observed that the adsorption capacity of adsorbents increases with the decrease of pH. Experimental data is presented in 5 figures. The adsorption capacity of adsorbent material was found to vary with water quality. According to the results of the investigation, recommendations for a project of an iron and organic matter removal plant that may supply the users with drinking water were developed. Keywords: adsorption capacity, natural adsorbent zeolites, organic matter, groundwater purification.
Article received 01 2002, given to print 04 2002.
COORDINATION OF ENVIRONMENT PROTECTION AND AGRICULTUREVilma SUDONIENESummaryFast economical development revealed the disagreements between economy and environment protection. In order to protect and improve natural environment, it is important to control the use of land in protected territories. Natural potential and existing problems of environment protection are to be evaluated not only in the country, but on a particular farm as well, considering the type and relief of the soil, the type and intensity of the farm, the state of land reclamation. Recommendations of environment protection are to be prepared for every farm and agricultural enterprise. The harm and environment pollution may be decreased by limiting the use of chemicals and developing ecological farming step by step. The essence of such farming is that organic metabolism in the soil is maintained without chemicals, which is achieved by applying organic fertilizers and their composts, widening the areas of fallow and leguminous plants, as well as improving agricultural engineering. Keywords: environment protection, ecology, farm, land.
Article received 01 2002, given to print 04 2002.
THE ANALYSIS OF LAND USE AND ITS MARKET PRICE IN ALYTUS REGIONDaiva MATONIENE, Virginija GURSKIENESummaryThe lack of information about the actual number of farmers and land areas possessed by them does not allow us to take economically motivated decisions. These investigations are insufficient, although necessary, therefore, looking for optimal ways of land use, it was suggested to carry out the research on the use of land in less favourable land areas. Cadastre vicinities in Alytus region were chosen as study objects. In the article the use of land have been analysed, correlation connection between agricultural land use productivity and market price and rent price of private agricultural land has been determined. Keywords: less favourable land areas, market price of the land.
Article received 01 2002, given to print 04 2002.
The aspects of land market value calculations while preparing economical background of land management projectsAudrius AleknaviciusSummaryThe final stage of land reform will introduce new tasks and works of land management for us. The most important tasks will include the improvement of current land use, readjustment of land plots formed during the land reform, and expansion of farms. Land management projects can be a great help while implementing all these works. The research of large farms was carried out in order to determine the current situation of plots dislocation. 224 farms in 9 districts were analyzed. The research showed, that farmland uses were formed sporadically and the distance to the fields did not correspond to normative. In the future these farms will be expanded and land management projects may help achieve more efficient land use. Land management projects are to be grounded economically. It should be profitable for a farmer to change the current land use. The price of land plays an important role in economical grounding calculations. The price of land makes up the biggest part of the cost when changing land use, which is hard to determine. The analysis of agricultural land prices was made in order to facilitate the calculations of price for land management specialists. 400 land transactions were analyzed in eight districts. Multiple regression analysis was used for this market research. The correlation can be described as stronger than average and strong in different districts. The price of land was greatly influenced by the size of land plot, distance to the state roads, distance to the district and region centers, and demand factor. The influence of the factors vary in different districts, which can be explained by the properties of local land markets and development stage of the whole land market in Lithuania. Keywords: land management projects, land readjustment and expansion projects, economical grounding of projects, agricultural land market, land prices.
Article received 01 2002, given to print 04 2002.
ANALYSIS OF FARMING CONDITIONS IN CENTRAL LITHUANIAVirginija GURSKIENE, Justinas MAKAUSKASSummarySearching for optimal methods of land exploitation, it was decided to research land exploitation in the regions with the best perspectives for agricultural development in Central Lithuania. Farming conditions in farms owned by farmers and other population in Central Lithuania have been analyzed: land users’ readiness for farming, their provision with buildings, the areas of owned land plots, the location of dwelling houses including production buildings with respect to the land plots, agricultural production results. The research determined the relation between the productivity of plants and farming areas in Central Lithuania. Keywords: farms, agricultural production, productivity of plants.
Article received 01 2002, given to print 04 2002. |
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