Volume 6 (2008)
  Special Issue

Contents


Pages

169-179 A. Annuk, E. Kokin, V. Palge, V. Põder and J. Lepa
Wind energy application problems in inland Estonia
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Wind energy application problems in inland Estonia

A. Annuk, E. Kokin, V. Palge, V. Põder and J. Lepa

Department of Energy Application, Institute of Technology,Estonian University of Life Sciences, Kreutzwaldi 56, 51014, Tartu;e-mail: andres.annuk@emu.ee

Abstract:

The inland regions of Estonia have not been seen as suitable economically for de-ployment of wind energy systems. Prices for technological development of wind turbines are going down, while energy prices are rising constantly. Since rural regions of Estonia are under-populated, the use of small scale wind turbine generators in these conditions is becoming more promising. Average wind speeds in mainland Estonia are 2.5–3.5 m s-1. Only a very small part of the wind speed frequency distribution (~4 ppm) exceeds 12 m s-1. More suitable for these regions are wind turbine generators which switch on at wind speeds less than 3 m s-1 and reach nominal output power at 11–12 m s-1. They have similar-looking power curves, so it is possible to model the first rising part of the curve up to maximal power by second order polynomial. Because the wind speed rarely exceeds 12 m s-1 in inland regions there is no need to model the whole power curve. The average power curve makes it possible to estimate an approximate en-ergy production of small scale wind turbine generators in a given region if the wind speed fre-quency distribution is known.

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181-189 A. Arlauskiene and S. Maiksteniene
Effect of sowing methods on the productivity of catch crops and soil nitrogen leaching
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Effect of sowing methods on the productivity of catch crops and soil nitrogen leaching

A. Arlauskiene and S. Maiksteniene

Joniskelis Experimental Station of the Lithuanian Institute of Agriculture,Joniskelis, Pasvalys district, LT–39301, Lithuania; e-mail: joniskelio_lzi@post.omnitel.net

Abstract:

The field experiment was carried out at the Lithuanian Institute of Agriculture’s Joniskelis Experimental Station in clay loam Cambisol from 2003–2005 to identifity the most effective sowing method of catch crops: red clover(Trifolium pratense L.), mixture of white clover (Trifolium repens L.) and Italian ryegrass (Lolium multiflorum Lamk.), and white mustard (Sinapis alba L.) in combination with different straw incorporation methods during the post–harvest period, to control mineral nitrogen content and nitrate leaching. The largest amount of aboveground mass 2.55 t ha-1 of dry matter was produced by undersown red clover with a longer growing season. The largest aboveground mass of aftercrop white mustard was formed in the plots of the treatments in which the seed was sown into stubble–broken soil or direct-sown into the stubble (2.43 and 2.53 t ha-1 of dry matter, respectively). Undersown legume crops during the post–harvest period produced the largest reduction in mineral nitrogen in the soil: red clover – 14.4%, white clover and Italian ryegrass mixture – 16.6%, compared with the treatment without catch crops. After incorporating cereal stubble shallowly at 10–12 cm by stubble-breaker, the contents of mineral nitrogen declined 5.9%, compared with that in the treatment with unbroken stubble. However, after incorporating by a stubble- breaker not only stubble but also straw, and having applied nitrogen fertilizer (N45) for its mineralization,the content of mineral nitrogen increased by 14.9%, compared with the treatment where the plots were stubble–broken without straw. While incorporating straw with the addition of mineral nitrogen fertilizer, 9.5% lower Nmin. content in the soil was found in the treatmentwhere catch crop white mustard was sown as the post–crop. In spring, higher contents of Nmin.in the soil and filtration water were found in the treatments in which nitrogen–rich biomass of legume crops had been incorporated in the autumn. With simultaneous incorporation of straw, nitrate nitrogen content in the soil filtration water declined (9.8%).

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191-198 R. Domeika, A. Jasinskas, D. Steponavičius, E. Vaiciukevičius and V. Butkus
The estimation methods of oilseed rape harvesting losses
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The estimation methods of oilseed rape harvesting losses

R. Domeika, A. Jasinskas, D. Steponavičius, E. Vaiciukevičius and V. Butkus

Department of Agricultural Machinery, Lithuanian University of Agriculture, Studentų 11, LT-53361 Kaunas, Lithuania; e-mail: Rolandas.Domeika@lzuu.lt

Abstract:

Oilseed rape harvesting losses, which occur during cutting, separation and cleaning and shaking, reach 5–10%; cutting and separation processes account for 80–90% of the total harvesting losses. A special test stand was prepared for the research of oilseed rape cutting and separation losses. It was established that the active twin-blade knife separator and the passive triangular separator on the header of a harvester have influence on the separation losses in 0.5 m on both sides of the separator motion line. Separation losses using the active twin-blade knife separator were twice less than using the passive triangular separator. The optimal active twin- blade knife separator moving speed is 5 km h-1. The analysis of the research results has revealed that traditional estimation methods of oilseed rape harvesting losses are not correct and it is necessary to use a 0.1×0.1 m wire frame for the estimation of cutting losses and a 0.1×0.5 m wire frame for the estimation of separation losses.

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199-205 H. Gerath, A. Sakalauskas, J. Köhn, Ch. Knitter, T. Geick and R. Böttcher
Extension of the raw material basis for the production of biogas through an efficient conversion of biomass
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Extension of the raw material basis for the production of biogas through an efficient conversion of biomass

H. Gerath¹, A. Sakalauskas², J. Köhn¹, Ch. Knitter¹, T. Geick¹ and R. Böttcher¹

¹Technical University Wismar, Department of Engineering, Section of Engine Construction /Processing and Environmental Technology, Chair of Processing of Biological Materials,Philipp-Müller Str. 14, D-239552 Wismar, Germany; e-mail: h.gerath@mb.hs-wismar.de
²Department of Agricultural Machinery, Lithuanian University of Agriculture,Studentų 11, LT-53361 Kaunas, Lithuania; e-mail: zum.katedra@lzuu.lt

Abstract:

The raw material base for biogas production shall be enlarged considerably by biomass processing that is efficient economically and in terms of energy consumption. At present, maize, whole plant corn silage and dung are of use primarily for the production of biogas. Since neither monocultures nor food competition are desirable, the research and development is focused on the expansion of raw materials such as beta beets, including beet leaf and lignocellulosic biomass, e.g. straw, dung, grassland cut and landscape management material.The raw materials are crushed and frayed out with special technologies to accelartehydrolysis in the biogas process. By this process further renewable raw materials can be used for fermentation, shortening the time for fermentation and increasing biogas yield. Moreover, the technology reduces cost because straw, dung and landscape management material, for example, are more reasonably priced than cultivated biomass. Furthermore positive influences on crop rotation, the reproduction of soil fertility and the conservation of nature can be expected.

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207-220 A. Jasinskas, G. Rutkauskas, A. Dravininkas and A. Mieldažys
Vibratory thickening of grass mass
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Vibratory thickening of grass mass

A. Jasinskas¹, G. Rutkauskas¹, A. Dravininkas¹ and A. Mieldažys²

¹ Institute of Agricultural Engineering of Lithuanian University of Agriculture,Raudondvaris, LT-54132 Kaunas reg., e-mail: aljas@mei.lt
² Lithuanian University of Agriculture,Kaunas-Akademija, LT-53361, e-mail: ifps.katedra@lzuu.lt

Abstract:

Flat surface inertia type vibrators in which the excitation force for thickening grass mass is received by turning the unbalanced mass were analyzed and evaluated. Directed and undirected action vibrators were manufactured and tested. The amplitude frequency characteristics of pressed grass mass were evaluated using a directed action grass mass pressing vibrator. It was concluded that resonant frequency depends essentially only on mass toughness qualities, and changes from 7.0 Hz when there is fodder goat’s rue (Galega orientalis Lam) mass of greater toughness, up to 15 Hz when thickening chopped maize mass of lesser toughness. The amplitude of grass mass pressure during resonance depends only on the mechanical resistance of the pressed mass. The amplitude of excitation power of goat’s rue and its mixes during resonance increased from 2.5 to 3 times but efficiency of mass pressure reduced. The calculated coefficients of pressure enhancement were equal to 5.5-5.8 when vibratory thickeners were used for pressing grass mass. The established repression of pressure on plant mass layer, while pressing mass on the surface and from the bottom of container, was 3.0-7.5 when using the directed action vibrator, and 4.8 when using the undirected action version. After evaluating the application of various tractors and vibratory grass mass thickeners for grass mass pressing it was found that in both cases the received efficiency rates of grass mass layer were similar. However, while using vibratory grass mass thickeners, these rates were even higher than using a wheeled tractor T-25A. The efficiency of mass thickening by centrifugal-directed action vibrator was evaluated by using an experimental trial. The results indicated that during vibratory thickening the grass layer was thickened intensely for 5-10 min. Therefore, it is advisable to use vibrators of this type for thickening grass layers of 0.4-0.6 m thickness. This vibrator resulted in good density of chopped maize – after 20 min of thickening (2×200 kg) the density of 510 kg/m3 was achieved and while thickening the first mix of 200 kg layer after 10 min 571 kg m-3 density was achieved. The densities of dry matter were 143 kg m-3 and 161 kg m-3 respectively. The investigation of the forage quality showed that it met the requirements of the highest-class silage.

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221-227 J. L. Kolchinskij
Problems of development of bio-energetics in the Russian Federation
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Problems of development of bio-energetics in the Russian Federation

J. L. Kolchinskij

Russian Consulting Centre of Agriculture, 141300, Moscow Region,Sergijevo-Posadskij district, Glinkovo 77; e-mail: Kolinfo@mail.ru

Abstract:

The current power balance in the world is formed mainly on the basis of three non- renewable hydrocarbonic energy sources – natural gas, oil and coal. Limitation of mineral stocks of fuel and the necessity of the maintenance of ecological safety has caused intensive growth in use of renewable energy and, in particular, bio-energy.The available resource potential of biomass in Russia is practically inexhaustible: itincludes significant reserves of bio-energy – in agriculture, arable land – 9% of world; in forestry – up to 25% of world’s timber reserves.Biofuel production is possible from the following raw materials: diesel biofuel, producedfrom oil of sunflower and oilseed rape; bioethanol, from sugar beet, corn, wood; biogas, from waste materials of animal production, food and wood processing.The project of offering proposals for state regulation of the development of bio-energeticshas been prepared, including two blocks: normative legislative documents regulating the development and maintenance of bioenergy; support of innovative financial activity – investment and taxation.Realization of the planned complex measures on acceleration of rates of bioenergeticsdevelopment in the Russian Federation will allow solving the following problems: to increase by 1.3–1.5 times the provision of animal production in fodder protein; lowering dependence of the agricultural sector on a stable rise in prices for traditional power resources; to provide a steady power supply for the agricultural population and agricultural production in the zones with decentralized electric supply.

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229-239 A. Kryževičienė, A. Jasinskas and A. Gulbinas
Perennial grasses as a source of bioenergy in Lithuania
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Perennial grasses as a source of bioenergy in Lithuania

A. Kryževičienė¹, A. Jasinskas² and A. Gulbinas²

¹ Lithuanian Institute of Agriculture, Instituto al.1, LT-58344 Akademija,Kėdainiai reg., Lithuania; e-mail: akryzeviciene@lzi.lt
² Institute of Agricultural Engineering Lithuanian University of Agriculture,Raudondvaris, LT-54132 Kaunas reg., Lithuania; e-mail: aljas@mei.lt

Abstract:

The study was designed to investigate the feasibility of cultivating perennial grasses as energy crops and their effect on soil agroecological potential. Field experiments with different grasses were conducted at the Lithuanian Institute of Agriculture from 2000–2004. Perennial grasses Phalaroides arundinacea L. and Bromopsis inermis Leysser were grown pure and in mixtures with legumes. Melilotus officinalis, Lupinus polyphyllus and Galega orientalis on a light gleyic loam soil (Cambisol) with a humus content of ca. to 2%. Pure swards of grasses were either fertilized with nitrogen or not. Mixtures did not receive any N. The swards were cut once per season when their biomass was used for combustion, and twice per season when their biomass was used for biogas. Dry matter yield of grasses in pure stands ranged from 6.4 to 9.3 t ha-1. Under normal weather conditions grass-legume mixtures without nitrogen (N) fertilization were higher yielding than N-fertilized (60+60 kg N ha-1) grass in pure swards, but the mixtures were lower yielding in the years with inadequate rainfall. In all cases mixtures had an important ecological advantage over N-fertilized grass swards. The swards had a positive soil conservation effect and maintained soil fertility potential.The energy potential of perennial grasses in both cases of biomass utilization variedaccording to DM yield variation and totaled up to 153 GJ ha-1; energy input for biofuel production amounted to 8.0 – 19.2 GJ ha-1. Our experimental evidence suggests that the tested swards sown on less fertile soil, amounting to over 0.5 million ha in Lithuania, would be able to produce to 4 million tons of biomass for energy production annually.

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241-247 A. Laurs and J. Priekulis
Robotic milking of dairy cows
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Robotic milking of dairy cows

A. Laurs and J. Priekulis

Institute of Agricultural Engineering, Latvia University of Agriculture,J. Čakstes bulv.5, LV3001, Jelgava, Latvia; e-mail: armins.laurs@promedia.lv

Abstract:

In countries with developed dairy farming milking robots are gaining wide popularity. The first milking equipment of this kind was installed in Latvia in 2007 and found interest among partitioning animal breeders and among scientists. The main feature of the milking robots is that cows can be milked independently, without human assistance and “on demand”. The aim of our research was to state how often the cows visited the robots, and to compare the load (capacity) and quality of the obtained milk to traditional milking equipment. In our experiments, the cows visited the robots 2.9 times a day, on average. Two robots that served a group of 73 cows were loaded to 65%. Therefore, the capacity can be enlarged to 110 cows. With the use of robots, milk quality indices were higher than milking with stall-type equipment with parallel location of animals.

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249-253 V. Maksarov and J. Olt
Analysis of the rheological model of the process of chip formation with metal machining
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Analysis of the rheological model of the process of chip formation with metal machining

V. Maksarov¹ and J. Olt²

¹Faculty of Technology Automated Mechanical Engineering, North-Western StateTechnical University, Sankt-Peterburg, Russia; e-mail: maks78.54@mail.ru
²Institute of Technology, Estonian University of Life Sciences, Tartu, Estonia;e-mail: jyri.olt@emu.ee

Abstract:

The present paper discusses mathematical modelling with regard to deformation processes resulting from chip forming and removal when cutting heavilyprocessed materials in a condition of non-homogeneous stress state, which can evoke undesirable self-excited oscillation. By describing the chip forming and removal process a synthesized rheological model was used.

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255-261 J. Palabinskis, A. Aboltins, A. Lauva and N. Karpova-Sadigova
The comparative material investigations of solar collector
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The comparative material investigations of solar collector

J. Palabinskis, A. Aboltins, A. Lauva and N. Karpova-Sadigova

Latvia University of Agriculture, Liela iela 2, Jelgava, LV – 3001, Latvia;e-mails: Janis.Palabinskis@llu.lv; Aivars.Aboltins@inbox.lv; Aigars.Lauva@inbox.lv;Nadezda.Karpova@llu.lv

Abstract:

The prices of energy resources used for grain drying are increasing year by year. In order to reduce costs, research into methods of saving energy in grain drying is in progress in the Research Laboratory of Grain Drying and Storing of the Faculty of Engineering, the LUA. Equipment for experimental research into the materials of solar collectors was built in the research laboratory for research purposes in 2005. The construction of the equipment allows for simultaneous comparative studies of two materials. The experimental data are metered and recorded in the electronic equipment REG. Cell polycarbonate PC (bronze, henceforth referred to as polycarbonate) with absorbers steel-tinplate and black-coloured wood was researched in comparison to the polyvinylchloride film (henceforth referred to as a film). The researches were made with different air velocities. The air heating degree ∆T in the solar collector is dependent on solar radiation I and air velocity v in the solar collector. In the experimental equipment, which is 1.5 meters in length, the air was heated to ∆T = 6°C at the velocity v = 0.5 m s-1.For theoretical investigation of the air heating power in solar systems the mathematicalmodel is applied; the solution can be used for estimation of different materials /absorbents/ and their heat source.

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263-269 I. Pelēce, U. Iljins, and I. Ziemelis
Theoretical calculation of energy received by semi-spherical solar collector
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Theoretical calculation of energy received by semi-spherical solar collector

I. Pelēce, U. Iljins, and I. Ziemelis

Latvia University of Agriculture, Liela str. 2, Jelgava LV3000; e-mail: ilze.pelece@llu.lv

Abstract:

Solar energy is widely used as an environmentally friendly energy source in many countries, Latvia among them. However, geographical and climatic conditions in Latvia, low maximal height of the sun and maximal irradiance, as well as comparatively great cloudiness, present particular challenges. Long days and the long path of the sun in summertime means traditional constructions of solar collectors are not efficient enough for use in Latvia.A new principle in the construction of the solar collector has been developed: a solarcollector with the absorber in the shape of a semi-sphere. It has advantages in comparison with the traditional fixed flat-plate model: it effectively receives both direct and diffuse solar radiation all day. In addition, it is durable against the destructive impact of the wind.This article reports theoretical calculations of received energy which have been carriedout, based on continual visible position of the sun in the sky. Results of these calculations have shown that on a clear sunny day, a semi-spherical collector with the base of 1 m2 receives 1.3 times more energy than a flat-plate collector positioned at optimal (approx. 40o) inclination, and 1.6 times more than the flat horizontal one. In cloudy conditions, the difference is greater because of greater diffused radiation.Such a semi-spherical solar collector has been constructed. Experimental investigation ofthe received heat energy from the semi-spherical solar collector will be carried out in field conditions this summer.

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271-280 S. Petkevičius, L. Špokas and D. Steponavičius
Substantiation of technological parameters of wet maize ear threshing
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Substantiation of technological parameters of wet maize ear threshing

S. Petkevičius, L. Špokas and D. Steponavičius

Department of Agricultural Machinery Lithuanian University of Agriculture,Studentu Str.15A, LT 53362 Akademija, Kaunas r., Lithuania;e-mail: Sigitas.Petkevicius@lzuu.lt

Abstract:

The paper presents the test results of wet maize ear threshing process during the period of 2003–2005. Grain biometrical indices, technological parameters of threshing apparatus, and the feed rate of the maize ears appeared to be the most significant causes of threshing drum losses, grain damage, and the threshed amount of grains thrown to the straw walkers. The concave clearance of the threshing apparatus is related with and depends on the internal diameter of the maize ears and cores. The concave clearance at the beginning should be approximately 10 mm smaller that the average ear diameter, and at the end it should be equal to core diameter. The clearance between the rasp bars and the transverse bar at the concave end should be controlled by the computer because the ears of different diameters are fed into the threshing apparatus. When wet ears (grain moisture content >35%) are threshed the drum losses are reduced by varying the speed of the drum rasp bars and the clearance between the drum and the concave. Rational rotational speed of the drum rasp bars is 17 m s -1. When wet ears are threshed the even ear flow rate should be supplied into the threshing apparatus. The medium load of one meter rasp bar length should be 0.82 kg (s m)-1.

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281-290 A. Pocius, P. Šniauka and A. Pushnov
Influence of dynamical factors on safe work with a fertilizer spreader
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Influence of dynamical factors on safe work with a fertilizer spreader

A. Pocius¹, P. Šniauka¹ and A. Pushnov²

¹Lithuanian University of Agriculture, Studentų 11, Akademija, LT―53361, Kaunas district,Lithuania; e-mail: antanas.pocius@lzuu.lt; povilas.sniauka@lzuu.lt
²Moscow State University of Environmental Engineering, Staraya Basmannaya 21/4,105066 Moscow, Russia; e-mail: pushnovas@gmail.com

Abstract:

The efficiency of mineral manure most often depends on the evenness of its distribution. The dynamics of the spread of the particles of the mineral manure in regard to the fixed and variable parameters of the imitative model of the spreader have been analyzed. The programmable location of a particle on soil depends on the movement trajectory of the particle on the disc and in the air, which eventually determine the final distribution of particles.The research considered the flow of the manure particles from the spread opening of themanure-box, the trajectory on the disc and in the air, the place of a particle on the surface of the ground as well as on how these trajectories depend on the characteristics of the spreader and particles. The trajectory of particle in the air is the function of its initial velocity and direction, by which the particle leaves the surface of the disc. It determines the final place of the particle on the surface of soil with respect to disc.One of the accidental factors influencing the trajectory of a particle is the impact of spreaderlean on hilly soil on the discharge angle of manure particles and the distance of particle fly in the distribution sector.The dependence of the spreading distance of the manure particles on the initial speed of theparticle and the trajectory angle of a disc has been obtained. It was established that when the aggregate moves, the trajectory angle changes due to the roughness of the ground from the one that was set constructively up to the largest value when a particle flies farthest.Under the influence of random factors, the angle between the spreader’s disc plane and aplane of soil surface can increase up to 8 degrees; therefore the distance of particle’s wafting increases.

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291-298 A. Požėlienė, S. Lynikienė, I. Šapailaitė and A. Sakalauskas
Utilization of strong electric field for special cleaning buckwheat seeds
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Utilization of strong electric field for special cleaning buckwheat seeds

A. Požėlienė¹, S. Lynikienė¹, I. Šapailaitė² and A. Sakalauskas²

¹Institute of Agricultural Engineering of Lithuanian Agricultural University, Instituto st. 20,Raudondvaris, LT-54132 Kauno r., Lithuania; e-mail: ausra@mei.lt, stely@mei.lt.
² Lithuanian Agricultural University, Studentų st. 15A, LT-53361, Kauno r., Lithuania;e-mail: ZUM.katedra@lzuu.lt

Abstract:

Buckwheat growers on ecological farms are confronted with a problem in seed cleaning – sorting – because they are not permitted to use chemical means to destroy weeds.The paper presents data about a special method of cleaning of wild radish seeds(Raphanus raphanistrum L.) from buckwheat seeds (Fagopyrum esculentum). The seed-preparing machines used the electric field can to separate seeds according to the unit of mechanical (mass, friction property and other) and electrical (conductivity, dielectric penetration and other) features, sorting and simulating germination. During the research, conveyer-type electric separators with a corona discharge field and three kinds of conveyer belt were used: rubber, armoured and flannel (shaggy-texture fabric).The following factors were determined during the cleaning tests: angle of friction withdifferent belt surfaces; seed output in fractions of separator; number of weeds; germination and mass of 1000 seeds in fractions.It was determined that buckwheat seeds’ average angle of friction with armoured surfaceis 36o (wild radish – 23o); rubberized surface – 41o (wild radish – 23o); flannel surface – 51o (wild radish – 36o); the greatest difference between the criterion of removing (detachment angle) wild radish from buckwheat is on the flannel belt; by the cleaning of non-conditional buckwheat seeds it is possible to get 62–80% of seeds to correspond to the requirements of the B or C1 category; germination of seeds from the first fraction of electro – separator exceeds germination of control seeds 18–26% and the increase in germination is substantial.

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299-306 J. Priekulis and V. Murikov
Research in liquid manure removal and storage technological versions on milk farms
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Research in liquid manure removal and storage technological versions on milk farms

J. Priekulis and V. Murikov

Institute of Agricultural Engineering, Latvia University of Agriculture,J.Čakstes bulv. 5, LV3001, Jelgava, Latvia; e-mail: Juris.Priekulis@llu.lv

Abstract:

Today loose housing of cows using boxes and a minimal amount of litter, resulting in liquid rather than litter manure is very common. However, there has not been much experience in manure utilization in Latvia.In our research we have discussed the possible outcome of liquid manure considering theamount of sewage water in liquid manure, the most economically effective technological versions of liquid manure removal from cow barns and transportation to storage reservoirs as well as different storage reservoir building costs, depending on their capacity and building type.It has been stated that the sewage water in the reservoir comprises 17% of the totalamount of liquid manure. Practically speaking, the operational costs of liquid manure removal systems do not depend on the kind of boxes for cow recreation, but rather on the technological equipment costs. In addition, the lagoon-type liquid manure reservoirs are cheaper. Installing cylindrical reservoirs with reinforced concrete panel walls increases the specific building costs 1.8 times, and with metal plate walls – 2.0-2.5 times.

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307-314 D. Rössel, H. Ortiz-Laurel, N. Kanswohl and M. Schlegel
Mathematical modelling for precisely improving inputs supply for crop production
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Mathematical modelling for precisely improving inputs supply for crop production

D. Rössel¹, H. Ortiz-Laurel², N. Kanswohl³ and M. Schlegel³

¹Campus San Luis Potosí, Colegio de Postgraduados, Iturbide No. 73, Salinas de Hgo., S.L.P.,C.P. 78600. México. e-mail: edietmar@colpos.mx
²Campus Cordoba, Colegio de Postgraduados, km 348, Carr. Fed. Córdoba-Veracruz, Córdoba,Veracruz, C.P. 94500, México. hlaurel@colpos.mx
³Institute for Farm Animals Sciences and Technology. University of Rostock, Justus-von-LiebigWeg 8, 18059 Rostock, Germany; e-mail: norbert.kanswohl@uni-rostock.de

Abstract:

Although farm size may make a difference in access to all precision agriculture techniques, farms including small-scale traditional crop cultivation will likely have access to some of them in the long term. For this farm sector, a mathematical model is being developed to assist decision-making for improved dosage of nutrients and pesticides for crops or feed for animals. The objective was to find out the maximum allowed permissible deficiencies in dosing of inputs compared with the number of repetitions for improving precision dosage each time it is spread to the field. The model is based on a number of specified repetitions and it calculates the amount of deficiency to be obtained. It is possible to find that, depending on the rate of application, there is a wide range of choices among different fertilizer formulae and their concentration of available nutrients. The higher the number of applications, the more precision could be achieved. This will make it possible to arrive at optimum application rates for each field point or for supplying a more precise rate of feed to the animals.

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315-327 E. Šarauskis, E. Vaiciukevičius, A. Sakalauskas,K. Romaneckas, A. Jasinskas and R. Lillak
Impact of sowing speed on the introduction of winter wheat seeds in differently-tilled soils
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Impact of sowing speed on the introduction of winter wheat seeds in differently-tilled soils

E. Šarauskis¹, E. Vaiciukevičius¹, A. Sakalauskas¹,K. Romaneckas², A. Jasinskas¹ and R. Lillak³

¹Department of Agricultural Machinery, Lithuanian University of Agriculture,Studentu St. 15A, LT-53361 Kauno r., Lithuania; e-mail: egidijus.sarauskis@lzuu.lt
²Department of Soil Management, Lithuanian University of Agriculture,Studentu St. 11, LT-53361 Kauno r., Lithuania
³Estonian Research Institute of Agriculture, Teaduse 13, 75501 Saku, Harjumaa, Estonia

Abstract:

Research tests in Europe disclosed that minimized soil tillage changes the soil qualities, the distribution of harvested crop residues (especially straw) in the soil, and the conditions of seed introduction into the soil, etc. In addition, completely different requirements are needed for design and technological parameters of the seeders in minimal soil tillage or no-tillage soils if compared with traditional seeders used in tilled soils.The paper describes the tests of winter wheat sowing in differently-tilled soils. Theimpact of the sowing speed of the winter wheat seeds on the even introduction and the distribution of the various size soil lumps in the seed bed layers was investigated. Furthermore, the change of the soil hardness and moisture content in various soil depths in differently-tilled soils was tested.Research suggested that the soil hardness in the winter wheat seed introduction zone inminimal soil tillage or no-tillage soils was approximately 250 kPa, and was significantly lower in tilled soil, i.e., 100 kPa. When winter wheat seeds were sown into no-tillage soil the sowing speed had greater impact on the composition of the soil lumps in the seed bed if compared with other more intensive soil tillage technologies. The tests disclosed that when the speed of the drill was increased from 8 to 12 km h-1, the number of small soil lumps (<2 mm) in all the layers of seed bed minimized and the amount of larger than 5 mm soil lumps maximized. The even introduction of seeds was negligible in minimal tillage soils.

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329-339 A. Satkus and A. Velykis
Modeling of seedbed creation for spring cereals in clayey soils
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Modeling of seedbed creation for spring cereals in clayey soils

A. Satkus and A. Velykis

Joniškėlis Experimental Station of the Lithuanian Institute of Agriculture,Joniškėlis, LT-39301 Pasvalys District, Lithuania; e-mail: joniskelio_lzi@post.omnitel.net

Abstract:

A model field experiment to establish the optimal parameters of seedbed structure for spring cereals was conducted at the Joniškėlis Experimental Station of the Lithuanian Institute of Agriculture from 2002–2004 on clay loam Gleyic Cambisol.We evaluated seedbed models for spring barley in small plots, where on the top seedbedsublayer (from 0 to 1.5 cm) the portion of desirable large-scale (>5 mm), on the middle sublayer (from 1.5 to 3.0 cm) of medium sized (2–5 mm) and on the bottom sublayer (from 3.0 to 4.5 cm) of smallest (<2 mm) soil structural aggregates made up to 40% in the 1st, 60% in the 2nd, 80% in the 3rd and 100% in the 4th model. Spring barley germination dynamics, emergence and growing intensity on clay loam soil were dependent on the structure of the seedbed and on the moisture content in the topsoil. When the topsoil moisture under the seedbed had decreased to 17.5 and 18.0% the spring barley seeds were germinating more intensively; more seed germinated in the seedbed where desirable soil structural aggregates account for 100 and 80% respectively in all seedbed sublayers, i.e. in the more fractionated seedbed, where bigger soil structural aggregates were taken to the surface, and smaller ones were concentrated deeper, closer to the seeds. When the moisture content in the topsoil was the highest (20.5%), the seedbed structure did not condition a consequent improvement in seed emergence. With increasing the seedbed fractionating, there was increasingly more moisture and higher porosity, less crust forming on the soil surface after rain, and less germination of annual weeds in the spring barley crop.

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341-348 M. Schlegel, N. Kanswohl, D. Rössel and A. Sakalauskas
Essential technical parameters for effective biogas production
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Essential technical parameters for effective biogas production

M. Schlegel¹, N. Kanswohl¹, D. Rössel² and A. Sakalauskas³

¹Professorship of Technology and Process Engineering of Sustainable Agriculture, Institute forFarm Animals Sciences and Technology, University of Rostock, Justus-von-Liebig Weg 8,18059 Rostock, Germany; e-mail: mathias.schlegel@uni-rostock.de
²Colegio de Postgraduados, Campus San Luis Potosí, Iturbide No. 73, Salinas de Hgo., S.L.P.,C.P. 78600. México. e-mail: edietmar@colpos.mx
³Department of Agricultural Machinery, Lithuanian University of Agriculture, Studentu 11,LT-53361 Kaunas, Lithuania; e-mail: zum.katedra@lzuu.lt

Abstract:

Rising agrarian raw material prices in 2006 had a negative impact on the biogas sector in Germany, leading to the search for potentials for optimisation of production. A problem is the workload of the block-type thermal power station (BTPS). This is caused by biogas process disturbances, construction errors, technical problems and management mistakes as well as by oversizing of the BTPS. Technical problems appear in particular with BTPS and aggregates, stirring devices and fermenter heatings, measuring and control technology as well as foil caps. The BTPS is an essential part of the economic efficiency of biogas production. A 2% increase in efficiency, to 40%, lowers the costs about 1 Cent kWh -1el . To achieve sufficientstirring power, the device type, heights and angle adjustment are vital. The substrate dosing engine must be adjusted to the particular substrates. The fermentation has to be controlled continuously. Parameters such as substrate amount, temperature, pH-factor, fermenter chamber load, gas amount and composition, ammonium concentration and short-chained fatty acids should be controlled regularly. Large temperature variations can lead to foam formation, resulting in a reduction of the gas yield. Disinfectants, antibiotics and a too tall fermenter chamber load can also have a negative influence. Low methane content often may often result from high sulphur and ammonia content in biogas composition, high aerial dosage accompanying desulphurisation as well as to coarse input material.

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349-357 D. Šimanskaitė
The impact of soil tillage minimization on sandy light loam soil
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The impact of soil tillage minimization on sandy light loam soil

D. Šimanskaitė

Lithuanian Institute of Agriculture, Instituto al. 1, Akademija, Kėdainiai district, Lithuania;e-mail: dana@lzi.lt

Abstract:

Experiments conducted during the period 2001–2005 at the Lithuanian Institute of Agriculture, were designed to evaluate the effects of plough and ploughless soil tillage and methods of sowing on an Endocalcari-Endohypogleyic Cambisol and to estimate their effects on soil physical properties and cereal yield. The experiment was set up in 2001 after pea harvesting. Our experimental evidence suggests that different soil tillage and sowing methods had a significant effect on soil structure, soil bulk density, soil penetration resistance, total and air-filled porosity, soil moisture and yield. In cereal crop rotation when winter wheat had been direct drilled after peas into minimally tilled soil the yield increased by 9.7%, when it had been direct drilled the yield tended to increase, compared with conventional soil tillage; the spring barley yield was 14.7% and 7.9% lower compared with conventional tillage; when it had been direct drilled the yield tended to increase compared with conventional tillage. When oats were direct drilled a non-significant yield reduction trend was observed, and when sown into minimally tilled soil the yield was similar (5.77 t ha-1) to that produced in the conventional soil tillage treatment (5.84 t ha-1). When peas were grown, both these simplified tillage methods significantly declined the yield, when peas were direct drilled, the yield declined by 44.0% and by 21.7% when drilled into minimally tilled soil by a direct drill.

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359-366 P. Šniauka and A. Pocius
Thermal weed control in strawberry
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Thermal weed control in strawberry

P. Šniauka and A. Pocius

Lithuanian University of Agriculture, Studentų g. 11, LT-53361 Akademija,Kauno r., Lithuania; e-mail: Povilas.Sniauka@lzuu.lt

Abstract:

Weed control with herbicides is impossible in perennial organic agricultural systems. Alternatively, in these systems, weeds can be destroyed mechanically, thermally or by mulching with a plastic film, to minimize negative weed influence, but not to exterminate all of them. Thermal weed control requires knowledge of the plants’ thermal sensitivity. The most common weeds growing between strawberry rows in Lithuania are shepherd’s purse (Capsella bursa), common groundsel (Senecio vulgaris L.) and common chick-weed (Stellaria media). We have been researching thermal sensitivity of these weeds. Research has shown the results of preheating a 2-mm diameter weed stem up to 70oC: shepherd’s purse (Capsella bursa) 2.0 s., common groundsel (Senecio vulgaris L.) – 2.4 s. and common chick-weed (Stellaria media) 1.7 s. Weeds between rows were burned as mechanical control is not allowed when strawberries are flowering. To estimate the effectiveness of this method, when thermal weed sensitivity was researched, the unit speed was selected depending on the degree of weed development.

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367-376 L. Špokas, D. Steponavičius and S. Petkevičius
Impact of technological parameters of threshing apparatus on grain damage
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Impact of technological parameters of threshing apparatus on grain damage

L. Špokas, D. Steponavičius and S. Petkevičius

Department of Agricultural Machinery Lithuanian University of Agriculture, Studentu Str.15A,LT 53362 Akademija, Kaunas r., Lithuania; e-mail: Liudas.Spokas@lzuu.lt

Abstract:

The paper describes the impact of the feed rate of cereals to the threshing apparatus, the movement speed of rasp bars and the clearance between the drum and the concave on the grain damage. When the feed rate of the cereals into the threshing apparatus is increased the grain damage decreases. Estimating the crop harvesting conditions the permissible flow of cereal is from 0.70 to 0.96 kg (s m)-1 for one meter of rasp bars length of the combine-harvester with four threshing-separation drums. The rasp bar speed of the threshing drum has the greatest impact on grain damage. When dry crop or cereals grown for seed (with moisture content of 12–14%) were harvested and the permissible limit crop flow was fed into the threshing apparatus the rational speed of drum rasp bars was 25 m s-1; when wet crop (moisture > 18%) was harvested the rational speed of drum rasp bars was from 31 m s-1 to 34 m s-1. Grain separation and their damage rate through all concave length increased when the clearance between the drum rasp bars and concave transverse bars at the beginning and at the end of the threshing apparatus was reduced. When combine-harvesters New Holland were used for the threshing of very dry crops (moisture content < 12%) the optimum clearance between the threshing drum rasp bars and the concave were 12–12 mm, for dry crops (moisture content 12–14%) the optimum clearance was 11–11 mm, and medium (14–16%) or high moisture (moisture content > 16%) the optimum clearance was 10–10 mm. The grain threshing losses were minimized until permissible (0.05%) by increasing the speed of the threshing drum rasp bars.

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377-385 D. Steponavičius, L. Špokas and S. Petkevičius
The influence of position of the first straw walker´s section on grain separation
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The influence of position of the first straw walker´s section on grain separation

D. Steponavičius, L. Špokas and S. Petkevičius

Department of Agricultural Machinery of Lithuanian University of Agriculture,Studentu St.15A, LT 53362 Akademija, Kaunas r., Lithuania;e-mail: Dainius.Steponavicius@lzuu.lt

Abstract:

The impact of the inclination angle of the first section (screen) of straw walkers on grain separation through the straw layer of various thicknesses has been tested in the laboratory. The straw feed rate on the straw walkers and the Froude number of the straw walkers (rotational speed of the walker crankshafts) was changed during the test. About 20% of the grains threshed and unseparated through the concave of the threshing device remained trapped in the straw layer fed on the straw walkers. It has been defined that the inclination angle of the first section of straw walkers were related to the straw throughput and the rotation speed of the walker crankshafts. The greatest number of grains was separated through the straw layer when it fell from the first section of straw walkers onto the second one. The optimum value of Froude number of the fourth straw walker assembly was 2.58 (the rotational speed of the crankshafts was 215 min-1), the inclination angle of the first straw walkers section was 22º, a step height was 0.28 m, the permissible limit straw feed rate on the straw walkers of dry straw (moisture content 9.8%) was 2.08 kg (s m)-1 on the layer with 0.43 m thickness because then only 3% of unseparated grains reach the fourth section of straw walkers with the straw. The intensity of grain separation can be controlled using the rotational speed of the crankshafts or the inclination angle of the first section of straw walkers.

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387-396 K. Tamm and R. Vettik
Case study: Economics of spring feeding in grassland
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Case study: Economics of spring feeding in grassland

K. Tamm and R. Vettik

Estonian Research Institute of Agriculture, Teaduse 13, Saku, Estonia;e-mail: Kalvi.Tamm@neti.ee

Abstract:

Change in world energy prices influences the price of mineral fertilisers. To meet the globally growing need for food farmers are extending the production of milk and meat, facilitating thereby an increase in manure production. The distance of the grassland from the farm centre and fertiliser prices influences farmers’ choices regarding the art and logistics of fertilising. The aim of this study is to compose a calculation model to compare the economic aspects of different fertilising options considering the grassland distance and the art of fertilising. The model contains components from the method applied to evaluate the rationality of exploitation of a field, considering the costs pertaining to field distance. Spring N feeding of grassland was simulated and five technologies were compared with the model.In calculations it was presumed that manure comes from a farm’s own production and thecosts arise only from hauling and distribution. In comparison with mineral fertiliser, these costs increase with driving distance; therefore it is economical to use only manure near the farm compound. In average Estonian forage production conditions, the N rate 75 kg ha-1 minimum value using cattle slurry distribution with a shallow injection system is more economical than using mineral fertiliser.It can be also concluded that compared to a distributor, using a tank truck for haulingslurry is beneficial on farther parcels (under the conditions in the simulation, farther than 4.2 5 km), as in those cases the hourly operation cost of the slurry distributor is very high.

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397-404 S. Toropov, B. Reppo, A. Leola and V. Palge
Modelling of heat exchange of milking parlour
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Modelling of heat exchange of milking parlour

S. Toropov, B. Reppo, A. Leola and V. Palge

Institute of Technology, Estonian University of Life Sciences,Kreutzwaldi 56, 51014 Tartu, Estonia

Abstract:

Unheated cowsheds are light constructions and can be referred to as sheds with outdoor climate, because the temperatures in the cowshed and milking parlour are almost identical to the outdoor climate. Control of the complicated temperature conditions in a milking parlour requires an adequate survey of the situation. The aim of the present study was to prepare a heat exchange model for a milking parlour and testing its workability by experimentally studying the indoor air temperature of the original object. The dynamic model of the heat balance of a milking parlour of an uninsulated cowshed is presented. Powersim Studio 7 environment was used for modelling the heat situation in a side-by-side milking parlour for 40 cows. Input and reference data of the model consist of the data on indoor climate measured at the original object, the farm for 600 cows, in winter. To get the necessary initial data for compiling the model, the indoor and outdoor temperatures of the milking parlour were measured, their daily values varying 8.75…17.81°C and 1.1…6.2°C, respectively. The composite model describes the actual situation with sufficient adequacy. So, with cows in the milking parlour, the measured indoor temperatures were practically of the same value withthose obtained by modelling, the values differed only by 3…4 deg that can be considered acceptable and applicable when evaluating the heat conditions of a milking parlour. The created dynamic heat exchange model for a milking parlour of an unheated cowshed is applicable for making practical decisions and can be used for design and control of the heat situation at the milking parlour.

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405-413 E. Vaiciukevičius, A. Sakalauskas, E. Šarauskis, R. Domeika and V. Butkus
The cleaning of caucasian goat’s rue chaff in the combine harvester cleaner
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The cleaning of caucasian goat’s rue chaff in the combine harvester cleaner

E. Vaiciukevičius, A. Sakalauskas, E. Šarauskis, R. Domeika and V. Butkus

Department of Agricultural Machinery, Lithuanian University of Agriculture,Studentu Str. 15A, LT-53361 Kaunas r., Lithuania; e-mail: ZUM.katedra@lzuu.lt

Abstract:

Caucasian goat‘s rue (Galega orientalis L.) is perennial grass which can be harvested as green mass and as seeds. The expansion of grasses with small seeds, such as Caucasian goat‘s rue has been stopped because of unsolved problems of yield processing and seed preparation in Lithuania.Caucasian goat‘s rue grass is usually harvested in the second half of July when the grassstems are still green and comprise about 43%. The pods of Caucasian goat‘s rue grass are in the top part of the plant. When the weather is windy the small amount of the pods are broken off the stem. The pod does not open by itself. Therefore, it is very important to duly adjust the threshing apparatus of the combine harvester to thresh all the seeds from the pods. The seed cleaning from the moist chaff of the green mass in the cleaner of the combine harvester is rather problematic because of significant seed losses.The agro-engineering of Caucasian goat‘s rue grasses has been investigated since1985.The yield harvesting losses exceed the permissible limit by 2–3 times. The greatest seed losses during the harvesting occur in the cleaner of the combine harvester. Thus the cleaning of the chaff of Caucasian goat‘s rue plants is a topical and acute issue that needs thorough investigation. The main research object is the separation of Caucasian goat‘s rue grasses through the upper sieve of the combine harvester cleaner: our paper describes our test results, which.largely depend on the cleaner load, the oblique air flow rate in cascades, and the gaps between the upper sieve openings.Tests show that 1.5 kg·(s·m)-1 of Caucasian goat‘s rue chaff can be fed into a combineharvester cleaner. At the air flow rate of 5 m·s-1 approximately 62.2% of the seeds are separated through the upper sieve in openings at the beginning of the upper sieve, resulting in seed separation losses of about 5%. When Caucasian goat‘s rue chaff is cleaned, 6 mm gaps should be left in upper sieve openings.

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415-421 T. Võsa and H. Meripõld
Growing technology and production costs for dry mass for direct burning and green mass for biogas of Galega Orientalis
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Growing technology and production costs for dry mass for direct burning and green mass for biogas of Galega Orientalis

T. Võsa and H. Meripõld

Estonian Research Institute of Agriculture (ERIA),Teaduse 13, Saku, Harjumaa 75501 Estonia;e-mail: taavi.vosa@eria.ee, heli.meripold@eria.ee

Abstract:

Demand for local and renewable energy source materials is accelerating the search for new crops for energy production. Goat’s rue or galega (Galega Orientalis Lam.) is known as a long-living and well-adapted rhizomatious legume used mainly for production of high quality forage. Thanks to its strong stem and nitrogen-fixing bacteria, an economically produced and harvested yield is feasible. As an energy source, its yield can be used in an alternative manner. In this paper estimated usage is based on a combination: direct burning of dry material (spring harvest) and ensilaging of summer harvest. Therefore the crop produces 2 yields and gives the best estimated yield. Calculations for production costs are made for pure crop and mixed grasses, since these mixes are most productive. Hauling to the usage site and costs related to material processing are not considered. Results show that establishing of the crop for pure stand and mix with grasses will cost 467.88 and 487.06 € ha-1, yearly costs are 378.56 and 421.81 € ha-1 respectively, crop finishing adds extra 111.38 € ha-1 in both cases.

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423-429 R. Zinkevičius
Influence of soil sampling for precision fertilizing
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Influence of soil sampling for precision fertilizing

R. Zinkevičius

Lithuanian University of Agriculture, Studentų g. 15a, Akademija,LT–53362 Kauno raj., e-mail: Remigijus.Zinkevicius@lzuu.lt

Abstract:

The determination of the amount of nutrients in various field locations was investigated using the differential global positioning system (DGPS) and the nutrient mapping (active phosphorus, potassium and acidity) was carried out in order to use precise fertilizer rates for the crops. Two standard methods of taking soil samples are compared: the linear, in which the soil samples are taken from a 1 ha size grid in 50 m length in front of the plot centre with stated DGPS coordinates and 50 m behind the plot centre, and the circular, in which the soil samples are taken at the distance of 10–30 m from the centre point of the plot.The paper analyses the technologies based on precision agricultural methods. The impactof two different soil sampling methods, i.e. the linear and the circular, on the nutrient mapping has been stated. The fertilization plans for the target crop yield are based on the amount of nutrients in different field locations. In precision farming, when different rates of fertilizers are applied in separate plots of the field, circular soil sampling enables saving 31–136 kg ha-1 of active material of phosphorus when linear method of soil sampling is used. Economy of potassium fertilizers in the case of usual farming is less, i.e. 11 kg ha-1 when the linear method of soil sampling is used, and 17 kg ha-1 of active material of potassium when circular method of soil sampling is used.

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