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Contents
PERENNIAL GRASS ON THE HILLS – ECOLOGICAL MEAN FOR THE REZERVOIR PROTECTIONAlgirdas NEDZINSKAS, Teresė NEDZINSKIENĖSummaryOver the period 1977-1999 at the Vokė Branch of the Lithuanian Institute of Agriculture and Veisiejai Agricultural School experiments have been conducted with the aim to establish the best suitable grasses for growing on the hills. Soil composition was soddy podzolic sandy loam laid with gravel. At Vokė hill there was 2-3O, and in Veisiejai – 9-10O steepness. It was established, that cocksfoot grown as under crop in winter rye was the most suitable even in the year when it was sown. Green mass yield of cocksfoot made up 35 t/ha, i.e. 5,14 t/ha of dry mass. In sowing year on the hills the highest green mass yield was that of bird’s foot trefoil and sainfoin. It made up 11-13 t/ha on the hill as well as on foot of the slope. At the depth of 0-50 cm in the soilcocksfoot accumulated 4,25 t/ha of air-dry mass of roots. Soil under cocksfoot had much better permeability as compared with the soil in clover field. It was established, that birds foot trefoil and sainfoin are the most suitable on sandy loam laid with gravel hills near the lakes, rivers and water bodies. These grasses can grow well at the same place for a long time. They protect hills against water erosion as well as water bodies against pollution. Keywords: soil erosion, soil protection, perennial grass, birds foot trefoil, sainfoin, cocksfoot.
Article received 09 2001, given to print 12 2001.
THE lakes SAPROPEL for improvement of soil PROPERTIESEugenija BAKŠIENĖSummaryTests were carried out at the Vokė Branch of the Lithuanian Institute of Agriculture with calcareous, organic and silicon sapropel on soddy podzolic sandy loamy soil (pH – 6.0, P2O5 – 130-230 and K2O – 150-210 mg/kg soil, humus – 1.7-2.05 %) within the period 1994-1999. 25 t/ha calcareous sapropel containing N – 0.62, P – 0.02, K – 0.03, Ca – 4.10, Mg – 0.52 %, 10 and 40 t/ha organic sapropel containing N – 5.07, P – 0.04, K – 0.16, Ca – 1.48, Mg – 0.22 %, 25 and 100 t/ha silicon sapropel containing N –1.11, P – 0.02, K – 0.55, Ca – 1.01, Mg – 0.78 % and its mixture with manure were investigated in the crop rotation. Calcareous sapropel and limestone decreased acidity of soil. Organic and silicon sapropel did not effect these indices. Only the bigger rate of organic (40 t/ha) and silicon (100 t/ha) sapropel increased in soil content of total nitrogen and humus. Fertilization with mineral fertilizer compensated the amount of mobile phosphorus and potassium, which was necessary for plants to grow. The application of sapropel had a positive influence on the quality of physical properties of sod-podzolic sandy loam soil. The organic and siliceous sapropel increased the humidity and porosity, and decreased the density of soil more than calcareous sapropel. Calcareous sapropel improved the mentioned soil physical indices more than limestone. Keywords: sapropel, limestone, manure, soil, properties.
Article received 09 2001, given to print 12 2001.
THE INVESTIGATIONS OF WASTEWATER TREATMENT IN LINKSMAKALNIS SETTLEMENTMidona DAPKIENĖ, Renė KUSTIENĖSummaryMany problems arise while cleaning small amount of wastewater in Lithuania. Strategical decisions are very urgent nowadays while seeking to choose good working and cheap cleaning technologies. The advantage of anaerobic wastewater treatment is minimal consumption of electric power, while its technological stability is not sufficient. This article deals with the efficiency and problems of wastewater treatment in Linksmakalnis anaerobic wastewater treatment plant (Kaunas district). The research was carried out in 2000 and 2001. It was established that the whole treatment system had not been functioning properly except the anaerobic wastewater treatment plant. Due to obstruction slope biofilter was not funkcioning. Meanwhile, the efficiency of the anaerobic wastewater treatment plant is twice smaller than projected. The dynamics of wastewater has been analysed and the influence of discharge of wastewater on cleaning quality has been evaluated. The time period of the remain of wastewater in the anaerobic treatment plant and the exploitation coefficient of its volume have been determined. It was revealed that the exploitation of the plant was only 7%. The reason was uneven distribution of wastewater in the anaerobic treatment plant. The means for solution of this problem are proposed in the article. The slope biofilter has to be reconstructed and included in the wastewater treatment process. Keywords: anaerobic plant, treatment efficiency, duration of wastewater retention, volume usage coefficient.
Article received 09 2001, given to print 12 2001.
RESEARCH OF WATER MANAGEMENT MODELS IN SOME EU COUNTRIESLeonas KATKEVIČIUS, Antanas MAZILIAUSKASSummaryThe management of water infrastructure in Lithuania is to date unsolved issue. Land reclamation infrastructure still belongs to the State which eliminates users from management. There are some differences in Lithuania to compare with most of EU countries regarding infrastructure itself, but there are some common principles, which could be adopted. The direct application of models from EU countries could be unreasonable, but in preparing some new models for Lithuania, the experience of EU countries should be considered adequately. There are 2.62 mln. ha of drained lands in Lithuania. Most of drainage systems are large enough why they should be managed and maintained in an associate way. The cooperative model for land reclamation infrastructure is a bit specific to compare with other fields of application. The social and economic status of rural citizens in Lithuania also influences the choice of cooperative model. Actually the conditions for the establishment of users groups or associations are not favorable in Lithuania. Why there is no motivation to invest in the infrastructure. The support system and models are not developed. The study analyses some experience of three water management association models in Germany and of one model in Netherlands. One of study cases is from the East Germany, where drainage systems are also large ones, as is the typical case in Lithuania. In all study cases one common principle has been noted: all beneficiaries from the activity of users association are taking part in the management and are contributing in kind or in cash to this activity. It is also important that other beneficiaries as municipalities, industries, companies, civil infrastructure, etc., would contribute to the water management. For this it is definitively indispensable to establish a rather clear rules which could not be avoided. The experience presented in this study should be useful in the case of Lithuania. Keywords: water management models,profiteers, obligations.
Article received 09 2001, given to print 12 2001.
THE INFLUENCE OF LAKE SAPROPEL ON YIELD, BALANCE OF SOIL NUTRIENTS AND NITROGENEugenija Bakšienė, Gražina palaitytėSummaryThe possibilities of sapropel of various chemical composition for fertilization have been investigated in the Voke Branch of Lithuanian Institute of Agriculture since 1994. The experiments were carried out in soddy podzolic sandy loamy soil (pH – 6.0, P2O5 – 130-230 and K2O – 150-210 mg/kg soil, humus – 1.7-2.05 %). There was investigated calcareous, organic and siliceous sapropel on the crop rotation. Manure and its mixture with sapropel were used in order to compare their activity with sapropel. The calcareous sapropel and manure mixtures increased the productivity of crop rotation more than limestone and manure mixtures. All rates of organic sapropel increased the yield of crops by 4-20 % and 10 t/ha of sapropel with 25 t/ha of manure increased the yield by 22-25 %. 50 and 100 t/ha rates of siliceous sapropel as well as the ones of manure increased the yield of crops by 18-30 %. The results of the experiments showed that the use of sapropel for fertilization gave a positive balance of nitrogen (except calcareous sapropel) and negative phosphorus and potassium balance in the soil. The bigest rates of sapropel and its mixture with manure had more influence on dry matter of winter rye roots. The employment of mineral fertilizer and manure mixture increased fixing of nitrogen by 24 %. Keywords: sapropel, yield, elements, balance, fixation.
Article received 09 2001, given to print 12 2001.
MIGRATION OF CHEMICAL ELEMENTS IN MANURED SOILLiudmila TRIPOLSKAJA, Danuta ROMANOVSKAJASummaryStudy of influence straw manure and solid manure, and also mineral fertilisers on migration of chemical elements in soddy – podzolic sandy loam soil were carried out in 1987-1998 y. at Voke branch of the Lithuanian institute of agriculture. Soil was fertilised straw manure and semi-liquid manure annually on N300, or straw manure (N600) in alternation with mineral NPK fertilisers. Were established that in soil-climatic conditions of East Lithuania from soddy – podzolic sandy loam soil per one year on the average infiltration are 28,7–35,9% of atmospheric precipitation. From unfertilised soil infiltration on 2,0-7,2 % are more, than from fertilised soil. The fertilising with manure increased leaching of nitrates. Their concentration in solution from fertilised soil has increased on the average on 72,6-77,6 mg/l NO-3, leaching - on 31,7-41,2 kg/ha N-NO-3 in comparison with the not fertilised soil. The losses of nitrogen from semi-liquid manure were a little bit more, than from straw manure. The substantial growth of nitrates concentration is observed at entering manure under winter. The fertilisers have not rendered influences on migration of nitrogen in ammonium form. Under influence of manure potassium concentration on 1,2-2,2 mg/l K+, magnum on 2,7-4,4 mg/l Mg++, chlorine on 9,6-22,6 mg/l Cl- has increased. Under superphosphate influence the concentration calcium and sulphates has increased. Manure and the mineral fertilisers of influence on phosphates migration have not rendered. Fertilising with manure or manure together with mineral fertilisers for 12 years has lowered soil acidity on 0,6 - 0,7 pH, has increased amount of absorbed bases on 15 - 22 mekv/kg and amount of available phosphorus on 76 - 188 mg/kg P2O5. Keywords: soil, fertilizers, chemical elemens migration.
Article received 09 2001, given to print 12 2001.
THE MODDELLING OF WATER PROTECTION PROPOSITIONS APPLYING VAGUE LOGICOjaras PURVINIS, Povilas ŠUKYSSummaryDecisions for water protection are usually made considering the data of water quality obtained by special laboratory researches. Such researches are very expensive and require much other input, too. The modelling of the pollution impact upon water quality is also problematic, especially when contamination factors are not defined numerically. The future contamination level may be foreseen only on the basis of the qualitative changes of pollution factors and their display conditions. Nevertheless, the qualitative estimation of water contamination is difficult to describe applying mathematical models. In this paper the possibilities of the application of vague logic for water protection are discussed. There are also presented data base and dependency function derivations on the basis of investigation results and estimations of experts. This work includes the modelling of conclusion solution as well. Keywords: pollution of streams, overlaid pollution levels, dependence functions,reliability of conclusions.
Article received 09 2001, given to print 12 2001.
WATER QUALITY IN SHAFT WELLS OF PYPLIAI VILLAGE, KAUNAS DISTRICTVida RUTKOVIENĖ, Saulius KUTRA, Laima ČESONIENĖSummaryThe research work deals with water quality in shaft wells in rural areas. Pypliai village (Kaunas district) was chosen as a study object. The studies were carried out in the period 1997-2000. Having analyzed the data obtained, it was determined that water in shaft wells in rural areas contained a big amount of nitrates and organic matter. The average of nitrate concentrations exceeded the biggest permissible rate in all study years. It was as follows: 65 mg/l (in 1997), 108 mg/l (in 1998), 60 mg/l (in 1999) and 115 mg/l (in 2000). In 1999, the number of wells with overtop permissible rate of nitrates was smallest and made up 39 % of all investigated wells, while in 1998 it was biggest and made up 66 % of all investigated wells. In the years 1998, 1999 and 2001 three wells were discovered with ammonia amount exceeding the required rate. In 1997 and 2000 such kind of wells made up 11 % and 13% of all investigated wells respectively. Water in more than a half of all wells did not meet the requirements for organic matter contamination. In the years 1998 and 2000, water in wells contained the biggest amounts of organic matter. Besides, it was polluted with nitrates in 16 %-22 % of all investigated wells. Water contamination in shaft wells fluctuated within the whole study period, therefore it was impossible to discover neither increasing nor decreasing tendency of it. Key words: water of shaft wells, nitrates, ammonium, nitrites, permanganate number, pH.
Article received 09 2001, given to print 12 2001.
THE PECULIARITIES OF NITROGEN MIGRATION IN SOILS WHERE SEWAGE SLUDGE WAS APPLIEDValerijus GASIŪNASSummary
Sewage sludge is a result product of wastewater treatment process. It is rich saturated with organic matter and is even more valuable than manure. Since sludge contains a great amount of nitrogen, there is a possible contamination of ground water with nitrogen compounds when rather big rates of sewage sludge are applied. The investigations of nitrogen migration processes were carried out in micro-test fields arranged in sand and loam soils. Sludge from household wastewater was applied in these fields. Its rates fluctuated from 50 to 260 t/ha of sludge of natural humidity. The amount of nitrogen that got into the soil together with sludge per one application varied from 300 to 3130 kg/ha, in respect to the study variant. The amount of humus increases in the soil depending on the applied rate of sludge. It has been established that when the amount of humus increases by 1% in sand and loam soils, the amount of total N increases by 0.075%. In spring, when biochemical processes get more intensive, the concentration of mineral nitrogen increases in topsoil, while in autumn its concentration decreases again due to nitrogen leaching with plants and its migration downwards. In autumn in the soil layer of 80-100 cm deep, unlike in the topsoil one, the amount of mineral nitrogen is bigger, although the soil is not fertilized. The change of mineral N at the period of investigation shows that cereals grown in non-fertilized sand soil use nitrogen much more quickly to compare with the ones grown in loam soil. Half of the mineral nitrogen amount was in the form of ammonium, another half of it was in the form of nitrates in the soil of the control variant. With the increase of sludge rate the part of mineral nitrogen in the form of ammonium is relatively decreasing because the changes of nitrogen amount in the form of ammonium are comparatively insignificant. With exactly the same rates of applied sludge the concentrations of nitrate nitrogen are higher in ground water of sand soil to compare with the ones in loam soil. A direct relation between the concentration of nitrate nitrogen in water and its amount in a vegetable soil layer and the layer of 80-100 cm deep was established. Having considered this dependence it is possible to foresee the contamination of ground water or drainage water with nitrogen compounds in sand and loam soils. Key words: sewage sludge, nitrogen migration, ground water.
Article received 09 2001, given to print 12 2001.
INVESTIGATIONS OF REGULIATION OF THE ŠVENTOJI RIVER BEDSaulius VAIKASAS, Vaclovas POŠKUSSummaryThe adjustment of Šventoji riverbed and bank erosion process in the town Ukmerge considering the state of dynamic equilibrium by the means of stream training works is described in the paper. The solution was found by removing the disadvantageous bed-armoring layer and by fortifying the eroded bank with rooting willow or structures of dam. It was established that bank rooting is more effective and cheaper measure. According to the comparative data of Canadian scientists, bends without riparian vegetation were found to be nearly 5 times less resistant detectable erosion during the flood events to compare with vegetated bends. An example of Šventoji river training by the help of bank rooting with willow as well as guideline of implementation and impact of groundwater fluctuation on willow plantation are presented in the article. Keywords: riverbed processes, riverbed regulation.
Article received 09 2001, given to print 12 2001.
POSSIBILITIES FOR water quality IMPROVEMENTHenrikas pauliukevičiusSummaryThe land structure of seven small river basins in the Middle Lithuania have been analyzed. The territory of river basins have been divided into four buffer zones - 0 - 200m, 200 - 500m, 500 - 1000m and over 1000m. The total areas of five land use categories (arable land, pastures and meadows, forests, wetlands and residential territories) in each zone have been calculated. The relationships between areas of land use categories and monthly concentrations and discharges of total nitrogen and phosphorus were investigated. The possibilities to improve the water quality are discussed. It was established, that the percentage of forests and wetlands tends to increase with the distance from the watercourses. From 15 to 93 percent of channels crossing agricultural areas in the river basins investigated have the natural buffer zones of bushes and wetlands of different width. The percentage of natural riparian zones increases with the area of river basin. The linear multiple regressions between land use categories and monthly concentrations of N and P total were closer and more reliable (R2 0,2 - 0,35) than those between land use categories and discharges of N and P (R2 0,05 - 0,1). The most reliable relations have been established in the areas closest to the channels. The attention should be focused on the territories nearest to watercourses when changing the land use in the river basin. Keywords: land use, nitrogen, phosphorus, runoff, concentration.
Article received 09 2001, given to print 12 2001.
MINERAL NITROGEN AMOUNT IN SOIL IN DIFFERENT AGRO-ECOSYSTEMSRamutė AKSOMAITIENĖSummaryIn 1996-2000 the experiments on ammonium and nitrate nitrogen amount and migration in drained carbonate gley (Endocalcari – Endohypogleyic Cambisols) light loam and sandy loam soil were carried out in five different crop rotation fields. The field experiments were fulfilled by the Experimental department at the Lithuanian Institute of Water Management. The researches were focused on the dependence of mineral nitrogen amount in soil upon climatic conditions, soil moisture, organic matter amount, crop structure, fertilization and yield. Soil mineral nitrogen amount reflects the existing balance among its formation, fixation and immobilization. Mineral nitrogen amount in investigated soils was extremely small and unstable: in spring in a 0-40-cm deep layer it was 10-69, in autumn it was 6-93 kg/ha, in a 0-100 cm deep layer it was 14-163 and 10-178 kg/ha respectively. Nitrate nitrogen made up 74-86 % of the total mineral nitrogen amount, but the straw ploughed in the soil increased ammonium nitrogen amount up to 50 %. Mineral nitrogen amount is mainly (96 %) predetermined by humus amount, C:N ratio in the soil and climatic conditions the influence of which on mineral nitrogen amount in the soil depends on the season of the year. In spring, with the increase of moisture gradient (R˛=0.527) nitrate nitrogen amount decreased in arable soil layer, while in autumn there was no such dependence. In spring a 0-40-cm deep layer contained 47.6 % of nitrogen, in autumn it contained 59.8 % of total nitrogen amount found in 0-100 cm deep layer. Considering average data of one crop rotation, no essential differences of mineral nitrogen amount in the soil exist between different crop rotations. However, with the increase of hoed plant area in a rotation field the ammonium and nitrate amounts increased (R˛=0.813 and 0.924) in a 0-60-cm deep layer, and with the increase of cereals area the amount of ammonium nitrogen decreased, while nitrate amount increased (R˛=0.470 and 0.937). No evident relation between nitrogen amount naturally found in a 0-100 cm deep layer and the one received with fertilizers, by-products, vegetative residues or yield was established. On the basis of nitrogen balance calculations it was established that fast mineralization processes prevented the increase of nitrogen content in the soil of all crop rotations. Biologically non-absorbed mineral nitrogen amount is leached from the soil. Keywords: mineral nitrogen, soil, climatic conditions, crop structure.
Article received 09 2001, given to print 2001 12.
THE MOST FAVORABLE TIME FOR LAND USE DETERMINATION WITH THE HELP OF REMOTE SENSING METHODSaulius KUTRA, Laima BERANKIENĖSummaryThe possibilities of obtaining satellite images under the conditions of Lithuania and the opportunities of their application in land use researches are analyzed in this paper. Perennial meteorological data show that cloudiness and fog may cause problems when choosing satellite images. The month of May includes the greatest amount of clear days in Lithuania (5,3 days, possibility reaches 17 %). Nevertheless, this month is suitable for the establishment of only certain land use types. Due to the peculiarities of spectral reflection, water bodies can be distinguished from other types of land use in course of the whole year, except for the period when they are frozen and covered with snow. Non – vegetation period (from November till March) and the beginning of spring (April and the first half of May) are favorable for the recognition of forests, winter crops and arable land. The period when all agricultural plants vegetate at the same time is very short (only 40 days, from June 10 tile July 20). The satellite Landsat 7 flies through 3 times during this period. This period gets longer and covers 90 days (May 10-July 30), when there is a possibility to receive two satellite images. But in this period of active vegetation the vegetation level of most agricultural plants would not help to distinguish them by spectral reflection. Such plants may be identified in a satellite image only when their vegetation level in extremely different from the one of other plants: for corn - August 10–September 20, for sugar beet – September 10 - October 20, etc. Perennial grass fields, which are mown or in which cattle is grazed, are most difficult to determine, because the amount of green mass varies in different fields as well as in one field. Therefore, spring period until grazing and haymaking would be the most favorable for the establishment of these areas. There results show that it is rater complicated to coordinate scanning time and objectives investigating land use with the helps of satellite images. Besides, meteorological conditions put a strong obstacle in our territory. Keywords: remote researches, sattelite image, scanning, spectral reflection, agricultural vegetation, cloudiness, vegetation height.
Article received 10 2001, given to print 12 2001.
THE PECULIARITIES OF DRAINAGE RUNOFF IN THE SOILS OF KARST ZONEAlvyda ŠAULIENĖ, Povilas ŠUKYSSummaryThe peculiarities of drainage runoff formation in moraine and glacial-lacustrive soils of the karst zone are analysed in this paper. It was established that the annual drainage runoff was influenced by the precipitation amount of the research period under meteorological condition. But no relation between monthly precipitation amount and drainage runoff head in investigated soils was found. Drainage runoff in the investigated soils was predetermined by the conditions of precipitation soaking. In glacial-lacustrive soils bigger runoff appeared from the soils drained using a thicker drain net. In moraine soils the runoff head was predetermined by the granuliometric composition of rocks soil formation: a bigger runoff occurred in the soils the draining layer of which contained smaller amount of clay particles. Keywords: precipitation, soil granuliometric composition, drainage, runoff.
Article received 09 2001, given to print 12 2001.
TOTAL NITROGEN BALANCE IN CROP ROTATION FIELDS WHEN SLURRY IS APPLIEDSimanas AŠKINIS, Stefanija MISEVIČIENĖSummaryThe carried out investigations allow us to estimate the impact of slurry spreading terms on total nitrogen balance under the conditions of intensive farming. When sugar beet, barley and summer rape was grown, nitrogen amounts that got into the soil were 232.4 kg/ha, 43.5 kg/ha and 65.8 kg/ha respectively. The biggest total nitrogen amounts were extracted from soil with the yield: 106.9 kg/ha (39.9 %) in the first study year, 70.9 kg/ha (65.8 %) in the second, 144.2 kg/ha (88.7 %) in the third and 129 kg/ha (86.9 %) in the fourth. Nitrogen leaching by drainage directly depends on nitrogen amount in the soil and runoff head. In the years 1995 and 1998, when drainage runoff heights were similar, leached nitrogen amounts from sugar beet field were 37.2 kg/ha (variant 1), 29.7 kg/ha (variant 2) and 29.6 (variant 3), and its amounts from summer rape field were 28.9 kg/ha, 26.8 kg/ha and 24.3 kg/ha respectively. The biggest amounts of nitrogen are leached in the variant where slurry is applied in autumn. Here the average leached amount of this compound is 23.8 kg/ha within a three-year period. When slurry is applied in spring, leached nitrogen amount is 3.5 kg/ha less, and when half-rate of slurry is applied in autumn and another half is applied in spring, leached nitrogen amount is 3.6 kg/ha less. Therefore, slurry should be applied in spring in order to reduce nitrogen leaching. In the first two study years total nitrogen balance was positive. Prolonged dryness precluded to utilize the whole nitrogen amount as well as to receive desirable yield. Negative nitrogen balance was obtained due to unfertilized clover. Summer rape caused negative nitrogen balance, too, because its vegetative mass needed big amounts of nitrogen. Key words: crop rotation, slurry, nitrogen balance, environment.
Article received 09 2001, given to print 12 2001.
THE INVESTIGATION OF RIVER BED ARMOURING PROCESSESSaulius VAIKASAS, Stasys OKUNEVIČIUSSummaryThe river bed armoring and its penetration has made a considerable impact on the river bed formation process. Analysis of governing equations and results of investigation show up that there are not one acceptable bed armoring process at the stage of it penetration. It was established, that complex solution of 6 independent equations of conservation laws of channel is more sinkable: water volume, bed material, water momentum conservation together with suspended-load, bed load transport and bed-material sorting. But there are some concentration, grain size and allocation calculation coefficients ascertainable in experiment way only. It was the main reason because a physical modelling of the Nemunas river bed armoring process according to governing criterion of Childs and sediment transport equations was carried out. It was found that there exists a new bed armoring formation after old penetration stages. Some results of the process is presented in the paper. Keywords: bed process, river bed shallowness, modelling of shallowness breaching.
Article received 09 2001, given to print 12 2001. |
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