Abstracts Vol 3: 1

In vitro rooting of PR 204/84 rootstock (Prunus persica x P. amygdalus) as influenced by mineral concentration of the culture medium and exposure to darkness for a period S. Fotopoulos and T.E. Sotiropoulos* N.AG.RE.F., Pomology Institute, P.O. Box 122, 59200 Naoussa, Greece Corresponding author; e-mail: thosotir@alfanet.gr Abstract. Reduction of the mineral concentration of MS medium to half the normal value increased the rooting percentage of PR 204/84 explants when IBA concentration was 2.5 μM, and mean root number when IBA concentrations were 2.5 and 5 μM. Root elongation was stimulated at all IBA levels on both full and half strength media. By increasing IBA concentration from 0 to 10 μM, an increase in the mean root number per shoot was observed in both media (full and half strength). The mean length of roots was not significantly affected by IBA and mineral concentration of the culture media. In a second experiment, after 12 days of culture of shoots in a dark room followed by 12 days in standard growth room conditions, rooting percentage of shoots increased in comparison to shoots grown for 24 days in standard growth room conditions with IBA concentrations 1 and 2.5 μM. Key words:* adventitious roots, indole-3-butyric acid, irradiance, Prunus micropropagation, rhizogenesis

Abstract. Reduction of the mineral concentration of MS medium to half the normal value increased the rooting percentage of PR 204/84 explants when IBA concentration was 2.5 μM, and mean root number when IBA concentrations were 2.5 and 5 μM. Root elongation was stimulated at all IBA levels on both full and half strength media. By increasing IBA concentration from 0 to 10 μM, an increase in the mean root number per shoot was observed in both media (full and half strength). The mean length of roots was not significantly affected by IBA and mineral concentration of the culture media. In a second experiment, after 12 days of culture of shoots in a dark room followed by 12 days in standard growth room conditions, rooting percentage of shoots increased in comparison to shoots grown for 24 days in standard growth room conditions with IBA concentrations 1 and 2.5 μM.

Key words: adventitious roots, indole-3-butyric acid, irradiance, Prunus micropropagation, rhizogenesis

Possibilities to use growth regulators in winter oilseed rape growing technology 2. Effects of auxin analogues on the formation of oilseed rape generative organs and plant winterhardiness V. Gavelienė¹, L. Novickienė¹, L. Miliuvienė¹, I. Brazauskienė² and D. Kazlauskienė¹ ¹Institute of Botany, Žaliųjų ežerų 49, Vilnius 08406, Lithuania; e-mail: leonida@botanika.lt ²Lithuanian Institute of Agriculture, Akademija 5051, Dotnuva parish, Kėdainiai distr., Lithuania Absract. The effect of the physiological analogues of auxin, the compounds TA-12 and TA-14, on the apex development, growth, winterhardiness and productivity formation of the winter oilseed rape var. ‘Casino’ was studied. Field experiments were carried out in 2002–2004 at the experimental station of the Lithuanian Institute of Agriculture, Dotnuva-Akademija. The results showed a positive effect of the compounds TA-12 (2·10^-3 M) and TA-14 (4·10^-3 M) on the autumnal development of oilseed rape plants and their preparation for overwintering: they stimulated the conversion of the apex vegetative phase into a generative one, promoted flower formation and further development, intensified monosaccharide accumulation in the root collum, and improved the winterhardiness of this culture. In test variants, the number of perished plants was lower than in the control. Data of our research demonstrated the functional involvement of sugars in the cold acclimation process of oilseed rape. Application of compounds TA-12 (417 g ha^-1) and TA-14 (369 g ha^-1) to plants in autumn at the 4^th–5^th leaf formation stage not only enhanced winterhardiness but also influenced the further growth in spring and formation of yield components. Under the effect of the compounds TA-12 and TA-14 the number of siliguae on the main and lateral branches racemes and their seed mass increased. All these factors contributed to an extra seed yield by 0.45 and TA-14 by 0.64 t ha^-1, respectively, the control yield being 3.53 t ha^-1. Key words: auxin physiological analogues TA-12 and TA-14, apex formation, oilseed rape, winterhardiness

Absract. The effect of the physiological analogues of auxin, the compounds TA-12 and TA-14, on the apex development, growth, winterhardiness and productivity formation of the winter oilseed rape var. ‘Casino’ was studied. Field experiments were carried out in 2002–2004 at the experimental station of the Lithuanian Institute of Agriculture, Dotnuva-Akademija. The results showed a positive effect of the compounds TA-12 (2·10^-3 M) and TA-14 (4·10^-3 M) on the autumnal development of oilseed rape plants and their preparation for overwintering: they stimulated the conversion of the apex vegetative phase into a generative one, promoted flower formation and further development, intensified monosaccharide accumulation in the root collum, and improved the winterhardiness of this culture. In test variants, the number of perished plants was lower than in the control. Data of our research demonstrated the functional involvement of sugars in the cold acclimation process of oilseed rape.

Application of compounds TA-12 (417 g ha^-1) and TA-14 (369 g ha^-1) to plants in autumn at the 4^th–5^th leaf formation stage not only enhanced winterhardiness but also influenced the further growth in spring and formation of yield components. Under the effect of the compounds TA-12 and TA-14 the number of siliguae on the main and lateral branches racemes and their seed mass increased. All these factors contributed to an extra seed yield by 0.45 and TA-14 by 0.64 t ha^-1, respectively, the control yield being 3.53 t ha^-1.

Physiology of diapause in pupae of Pieris brassicae L. (Lepidoptera: Pieridae) K. Jõgar¹, L. Metspalu¹, K. Hiiesaar¹, A. Luik¹, A.-J. Martin¹, M. Mänd¹, R. Jaaniso² and A. Kuusik¹ ¹Institute of Agricultural and Enviromental Sciences, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: katrinj@eau.ee ²Institute of Physics University of Tartu, Riia 142, 51014 Tartu, Estonia Abstract. Respiration patterns, water loss and heart activity were investigated during the first three months of diapause in non-acclimated pupae of Pieris brassicae. To observe and record diverse events during pupal diapause, a complex apparatus was used: a micro-calorimeter, an electrolytic respirometer, a fibre-optical oxygen sensor, a flow-through respirometer (infrared gas analyzer), an infra-red actograph and a thermocouple cardiograph. Most of the pupae (about 80%) reared in 2004 were characterised as long-cycle individuals whose discontinuous gas exchange cycles (DGCs) were very regular and lasted 26 hours on average. The remainder of the pupae studied were short-cycle individuals displaying irregular DGCs lasting less than 2 hours. Standard metabolic rates (SMR) measured during the first month of diapause between long- and short-cycle pupae did no differ significantly, being about 0.018 ml O₂ g^-1 h^-1. At the same time, water loss rate (WLR) in long- and short-cycle pupae differed significantly, being 1.07 and 1.61 mg g^-1 day^-1, respectively. During the first three months of diapause, the values of SMR and WLR did not change significally in the long-cycle pupae. In the short-cycle individuals, SMR and WLR thereupon increased gradually during the months, but the values of SMR never reached the levels characteristic of pharate adult development. The heartbeat reversal was characteristic for both the long- and short-cycle individuals but heart pauses in the first pupal group were regular, lasting 20–30 min, whereas in the second group the heart pauses were shorter and irregular. From the results we concluded that the intensity of pupal diapause varied individually despite the apparently similar developmental conditions of the individuals, however, some hidden factors were obviously involved in diapause induction. The primary cause of the enhanced water loss in the short-cycle pupae was obviously the disturbing of the water conserving mechanisms due to the irregular gas exchange. Key words: Pieris brassicae, pupal diapause, discontinuous gas exchange cycles, (C)FV and (C)FO cycles, standard metabolic rate, water loss rate, heart activity, cold tolerance

Physiology of diapause in pupae of Pieris brassicae L. (Lepidoptera: Pieridae)

K. Jõgar¹, L. Metspalu¹, K. Hiiesaar¹, A. Luik¹, A.-J. Martin¹, M. Mänd¹, R. Jaaniso² and A. Kuusik¹

¹Institute of Agricultural and Enviromental Sciences, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: katrinj@eau.ee
²Institute of Physics University of Tartu, Riia 142, 51014 Tartu, Estonia

Abstract. Respiration patterns, water loss and heart activity were investigated during the first three months of diapause in non-acclimated pupae of Pieris brassicae. To observe and record diverse events during pupal diapause, a complex apparatus was used: a micro-calorimeter, an electrolytic respirometer, a fibre-optical oxygen sensor, a flow-through respirometer (infrared gas analyzer), an infra-red actograph and a thermocouple cardiograph. Most of the pupae (about 80%) reared in 2004 were characterised as long-cycle individuals whose discontinuous gas exchange cycles (DGCs) were very regular and lasted 26 hours on average. The remainder of the pupae studied were short-cycle individuals displaying irregular DGCs lasting less than 2 hours. Standard metabolic rates (SMR) measured during the first month of diapause between long- and short-cycle pupae did no differ significantly, being about 0.018 ml O₂ g^-1 h^-1. At the same time, water loss rate (WLR) in long- and short-cycle pupae differed significantly, being 1.07 and 1.61 mg g^-1 day^-1, respectively. During the first three months of diapause, the values of SMR and WLR did not change significally in the long-cycle pupae. In the short-cycle individuals, SMR and WLR thereupon increased gradually during the months, but the values of SMR never reached the levels characteristic of pharate adult development. The heartbeat reversal was characteristic for both the long- and short-cycle individuals but heart pauses in the first pupal group were regular, lasting 20–30 min, whereas in the second group the heart pauses were shorter and irregular.

From the results we concluded that the intensity of pupal diapause varied individually despite the apparently similar developmental conditions of the individuals, however, some hidden factors were obviously involved in diapause induction. The primary cause of the enhanced water loss in the short-cycle pupae was obviously the disturbing of the water conserving mechanisms due to the irregular gas exchange.

Key words: Pieris brassicae, pupal diapause, discontinuous gas exchange cycles, (C)FV and (C)FO cycles, standard metabolic rate, water loss rate, heart activity, cold tolerance

Exogenous effect of gibberellins and jasmonate on tuber enlargement of Dioscorea opposita S. K. Kim¹, J. T. Kim², S. W. Jang³, S. C. Lee², B. H. Lee¹ and I. J. Lee² ¹Institute for Bioresources Research, Gyeongbuk Provincial Agricultural Technology Administration, Andong 760-891, Korea ²Division of Plant Biosciences, Kyungpook National University, Daegu 702-701, Korea; e-mail: ijlee@knu.ac.kr ³Korea Tobacco and Ginseng Central Research Institute, Daejon 305-805, Korea The authors (S. K. Kim and J. T. Kim) have equally contributed to this study. Abstract. We have examined the single and combinational effect of gibberellins (GA₃, GA₄₊₇) and jasmonic acid (JA) on enlargement of Chinese yam tubers in field. In a single treatment, gibberellin promoted the tuber enlargement by one time application, whereas the lowest concentration (100ppm) led to the highest tuber yield rather than accumulative application. The effect of GA₄₊₇ enhancing tuber yield was only recognised at the highest concentration by a single treatment. Tuber weight was decreased at the highest JA concentration, otherwise the lowest concentration of JA (5 ppm) significantly promoted the tuber weight by a single treatment (FS1). The combination of GA 50 ppm plus JA 5ppm enhanced remarkably the tuber weight by a single treatment (FS1). It is suggested that the combined treatment of yam plants with both gibberellic acid and jasmonic acid has promoted tuber yield. Key words: Dioscorea opposita, gibberellin, jasmonate, tuber yield

Exogenous effect of gibberellins and jasmonate on tuber enlargement of Dioscorea opposita

S. K. Kim¹, J. T. Kim², S. W. Jang³, S. C. Lee², B. H. Lee¹ and I. J. Lee²

¹Institute for Bioresources Research, Gyeongbuk Provincial Agricultural Technology Administration, Andong 760-891, Korea
²Division of Plant Biosciences, Kyungpook National University, Daegu 702-701, Korea; e-mail: ijlee@knu.ac.kr
³Korea Tobacco and Ginseng Central Research Institute, Daejon 305-805, Korea
The authors (S. K. Kim and J. T. Kim) have equally contributed to this study.

Abstract. We have examined the single and combinational effect of gibberellins (GA₃, GA₄₊₇) and jasmonic acid (JA) on enlargement of Chinese yam tubers in field. In a single treatment, gibberellin promoted the tuber enlargement by one time application, whereas the lowest concentration (100ppm) led to the highest tuber yield rather than accumulative application. The effect of GA₄₊₇ enhancing tuber yield was only recognised at the highest concentration by a single treatment. Tuber weight was decreased at the highest JA concentration, otherwise the lowest concentration of JA (5 ppm) significantly promoted the tuber weight by a single treatment (FS1). The combination of GA 50 ppm plus JA 5ppm enhanced remarkably the tuber weight by a single treatment (FS1). It is suggested that the combined treatment of yam plants with both gibberellic acid and jasmonic acid has promoted tuber yield.

Key words: Dioscorea opposita, gibberellin, jasmonate, tuber yield

Effect of fertilisation systems on the balance of plant nutrients and soil agrochemical properties Irena Kristaponyte Joniskelis Research Station of the Lithuanian Institute of Agriculture Joniskelis LT-39301 Pasvalys district. Lithuania; e-mail: joniskelio_lzi@post.omnitel.net Fax: 370-71-38224 Abstract. Clay loam soils are rich in available potassium, however, they contain a low or moderate content of phosphorus. At the Lithuanian Institute of Agriculture's Joniskelis Research Station trials were carried out over the period of 1960–2000 on a Endocalcari-Endohypogleyic Cambisol (Cmg-n-w-can) – a clay loam soil in a five-course crop rotation, in which we investigated mineral, organic and organic-mineral fertilisation systems. Results of the sixth rotation showed that the annual application of mineral N₅₆P₄₈K₆₀ fertilisers resulted in an increase of the content of available phosphorus in 5 mg kg^-1 of the soil, and the reduction of potassium content in 3 mg kg^-1 of the soil, compared with the initial level. In the organic fertilisation system, the application of only 80 t ha^‑1 of farmyard resulted, compared with the mineral fertilisation system, in a humus content increase in the plough layer by 0.12 percentage units and that in the phosphorus content by 26.0 mg kg^-1 and potassium content by 31.0 mg kg^‑1. In this system the crop productivity, compared with unfertilised crops, increased by 34.1%, however, compared with the mineral fertilisation system, it declined by 14.1%. In the organic-mineral fertilisation system, the application of 40, 60 and 80 t ha^‑1 of farmyard manure and NPK fertilisers in the same amount as in the mineral fertilisation system resulted in the following increases – soil humus content by 0.18; 0.24 and 0.21 percentage units, phosphorus content by 41.0, 61.0 and 61.0 mg kg^-1, potassium content by 36.0; 46.0 and 54.0 mg kg^-1, and crop rotation productivity by 6.2, 7.6 and 7.8, respectively, compared with the mineral fertilisation system. Key words: heavy loam brown soil, fertilising system, crop rotation, phosphorus and potassium, humus

Effect of fertilisation systems on the balance of plant nutrients and soil agrochemical properties

Irena Kristaponyte

Joniskelis Research Station of the Lithuanian Institute of Agriculture Joniskelis LT-39301 Pasvalys district. Lithuania; e-mail: joniskelio_lzi@post.omnitel.net
Fax: 370-71-38224

Abstract. Clay loam soils are rich in available potassium, however, they contain a low or moderate content of phosphorus. At the Lithuanian Institute of Agriculture's Joniskelis Research Station trials were carried out over the period of 1960–2000 on a Endocalcari-Endohypogleyic Cambisol (Cmg-n-w-can) – a clay loam soil in a five-course crop rotation, in which we investigated mineral, organic and organic-mineral fertilisation systems. Results of the sixth rotation showed that the annual application of mineral N₅₆P₄₈K₆₀ fertilisers resulted in an increase of the content of available phosphorus in 5 mg kg^-1 of the soil, and the reduction of potassium content in 3 mg kg^-1 of the soil, compared with the initial level. In the organic fertilisation system, the application of only 80 t ha^‑1 of farmyard resulted, compared with the mineral fertilisation system, in a humus content increase in the plough layer by 0.12 percentage units and that in the phosphorus content by 26.0 mg kg^-1 and potassium content by 31.0 mg kg^‑1. In this system the crop productivity, compared with unfertilised crops, increased by 34.1%, however, compared with the mineral fertilisation system, it declined by 14.1%. In the organic-mineral fertilisation system, the application of 40, 60 and 80 t ha^‑1 of farmyard manure and NPK fertilisers in the same amount as in the mineral fertilisation system resulted in the following increases – soil humus content by 0.18; 0.24 and 0.21 percentage units, phosphorus content by 41.0, 61.0 and 61.0 mg kg^-1, potassium content by 36.0; 46.0 and 54.0 mg kg^-1, and crop rotation productivity by 6.2, 7.6 and 7.8, respectively, compared with the mineral fertilisation system.

Key words: heavy loam brown soil, fertilising system, crop rotation, phosphorus and potassium, humus

Effect of k-casein and ß-lactoglobulin genotypes on the milk rennet coagulation properties I. Kübarsepp, M. Henno, H. Viinalass and D. Sabre Institute of Veterinary Medicine and Animal Science, Estonian Agricultural University, Kreutzwaldi 1, 51014 Tartu, Estonia; e-mail: ivik@eau.ee Abstract. Purpose of this study was to find connections between milk renneting properties of dairy breeds in Estonia and the genetic variants of k-casein and ß-lactoglobulin. Milk (n = 2161) and blood (n = 87) samples were taken from Põlula Research Farm where all dairy cattle breeds are represented: Estonian Holstein (EHF) - 45 cows, Red-and-White Holstein (RHF) - 12 cows, Estonian Red (EPK) - 26 cows and Estonian Native (EN) - 4 cows) raised in Estonia. Milk samples were analysed for fat, protein, calcium, and phosphorus contents, somatic cell count, and rennet coagulation parameters. Rennet coagulation properties of milk from cows of four experimental groups were higher in EK group. No noncoagulated milk samples were observed in this group. Estonian Red breed has the second-best rennet coagulation properties of milk. Percentage of noncoagulated milk samples in the group of EPK (3.6%) was lower than in the groups of EHF and RHF (percentage of noncoagulated milk samples 5.0% and 7.7%, respectively). All measured rennet coagulation parameters were significantly better for the k-casein BB and worse for the k-casein AA genotype. k-Cn BB exhibited also the lowest percentage of noncoagulated milk samples and samples that did not reach K₂₀ 30 min after enzyme addition. ß-Lg genotypes had no significant effect on milk rennet coagulation parameters, but it was possible to observe tendencies that milk rennet coagulation time was the shortest and the percentages of noncoagulated milk samples and samples with poor coagulation properties (NK₂₀) were lower for the ß-Lg AA genotype. Better milk rennet coagulation properties among native breeds are explicable with a higher frequency of k-Cn B allele. The frequency of k-Cn B allele has been decreased among Estonian Holstein cows. Key words: milk coagulation properties, milk proteins, k-casein, ß-lactoglobulin, genetic variants

Effect of k-casein and ß-lactoglobulin genotypes on the milk rennet coagulation properties

I. Kübarsepp, M. Henno, H. Viinalass and D. Sabre

Institute of Veterinary Medicine and Animal Science, Estonian Agricultural University, Kreutzwaldi 1, 51014 Tartu, Estonia; e-mail: ivik@eau.ee

Abstract. Purpose of this study was to find connections between milk renneting properties of dairy breeds in Estonia and the genetic variants of k-casein and ß-lactoglobulin. Milk (n = 2161) and blood (n = 87) samples were taken from Põlula Research Farm where all dairy cattle breeds are represented: Estonian Holstein (EHF) - 45 cows, Red-and-White Holstein (RHF) - 12 cows, Estonian Red (EPK) - 26 cows and Estonian Native (EN) - 4 cows) raised in Estonia. Milk samples were analysed for fat, protein, calcium, and phosphorus contents, somatic cell count, and rennet coagulation parameters. Rennet coagulation properties of milk from cows of four experimental groups were higher in EK group. No noncoagulated milk samples were observed in this group. Estonian Red breed has the second-best rennet coagulation properties of milk. Percentage of noncoagulated milk samples in the group of EPK (3.6%) was lower than in the groups of EHF and RHF (percentage of noncoagulated milk samples 5.0% and 7.7%, respectively). All measured rennet coagulation parameters were significantly better for the k-casein BB and worse for the k-casein AA genotype. k-Cn BB exhibited also the lowest percentage of noncoagulated milk samples and samples that did not reach K₂₀ 30 min after enzyme addition. ß-Lg genotypes had no significant effect on milk rennet coagulation parameters, but it was possible to observe tendencies that milk rennet coagulation time was the shortest and the percentages of noncoagulated milk samples and samples with poor coagulation properties (NK₂₀) were lower for the ß-Lg AA genotype. Better milk rennet coagulation properties among native breeds are explicable with a higher frequency of k-Cn B allele. The frequency of k-Cn B allele has been decreased among Estonian Holstein cows.

Key words: milk coagulation properties, milk proteins, k-casein, ß-lactoglobulin, genetic variants

Invasion of broad-leaved weeds into alfalfa stand during time of utilisation of alfalfa stands in low-input farming system R. Lillak, A. Linke, R. Viiralt and T. Laidna Institute of Agricultural and Environmental Sciences, Estonian Agricultural University, Kreutzwaldi 56, 51014 Tartu, Estonia; e-mail: rein_lillak@hotmail.com Abstract. The objective of the investigation was to determine the percentage and yield of weeds in lucerne stands during the productive period. Different cutting regimes (first and final cut date and cutting frequency) were applied as treatments for estimating the extent of the invasion of weeds. Experiment 1 was conducted in 1980–1995 with the locally-bred alfalfa cv. Jõgeva 118 to study the connection between the invasion of broad-leaved weeds in the stand and weather conditions. Experiment 2 was carried out in 1991–2003 to investigate the impact of the first cut date and cutting frequency on the total DM yield of the alfalfa stand (cv. Karlu), partial DM yield of weeds, and the percentage of weeds in the stand. Experiments 3 and 4, Medicago sativa type WL 252 HQ variety (US), were sown in Tartu and Koonu to study weed spreading and alfalfa production at different locations. The results showed that management system had a strong impact on the productivity and competition ability of alfalfa and the invasion of weeds into the stand. Decreasing cutting frequency to 2–3 harvest times per season and performing the final cut in the second half of September or in early October allowed us to successfully depress the weeds in the alfalfa stands under Estonian pedoclimatic conditions. It is especially important to avoid more intensive management when extremely rainy and cool, or opposite droughty, weather conditions (total precipitation from May to September below the equivalent of 200 mm) dominate during vegetation period. Key words: alfalfa, weeds, DM yield, harvesting schedule, weather conditions, low-input farming system

Invasion of broad-leaved weeds into alfalfa stand during time of utilisation of alfalfa stands in low-input farming system

R. Lillak, A. Linke, R. Viiralt and T. Laidna

Institute of Agricultural and Environmental Sciences, Estonian Agricultural University, Kreutzwaldi 56, 51014 Tartu, Estonia; e-mail: rein_lillak@hotmail.com

Abstract. The objective of the investigation was to determine the percentage and yield of weeds in lucerne stands during the productive period. Different cutting regimes (first and final cut date and cutting frequency) were applied as treatments for estimating the extent of the invasion of weeds. Experiment 1 was conducted in 1980–1995 with the locally-bred alfalfa cv. Jõgeva 118 to study the connection between the invasion of broad-leaved weeds in the stand and weather conditions. Experiment 2 was carried out in 1991–2003 to investigate the impact of the first cut date and cutting frequency on the total DM yield of the alfalfa stand (cv. Karlu), partial DM yield of weeds, and the percentage of weeds in the stand. Experiments 3 and 4, Medicago sativa type WL 252 HQ variety (US), were sown in Tartu and Koonu to study weed spreading and alfalfa production at different locations. The results showed that management system had a strong impact on the productivity and competition ability of alfalfa and the invasion of weeds into the stand. Decreasing cutting frequency to 2–3 harvest times per season and performing the final cut in the second half of September or in early October allowed us to successfully depress the weeds in the alfalfa stands under Estonian pedoclimatic conditions. It is especially important to avoid more intensive management when extremely rainy and cool, or opposite droughty, weather conditions (total precipitation from May to September below the equivalent of 200 mm) dominate during vegetation period.

Key words: alfalfa, weeds, DM yield, harvesting schedule, weather conditions, low-input farming system

Assessment of the agrochemical properties of the soil using the extraction solution Mehlich 3 in Estonia V. Loide¹, M. Nõges² and J. Rebane² ¹Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: valli.loide@mail.ee ²Agricutural Research Centre, Teaduse 4/6, 75 501 Saku, Estonia; e-mail: noges@pmk.agri.ee Abstract. To determine the requirement of macro- and microelements, seven extraction solutions have been employed in Estonian practice. Double lactate (DL) extraction has been used for determination of the phosphorus and potassium requirement, ammonium lactate (AL) extraction for determination of the calcium and magnesium requirement, and five more different extractions have been used for determination of microelements. Hence the need for a more appropriate extraction solution was due to the large number of the extraction solutions used until now, which made determination of the fertiliser requirement less efficient; also, in some cases, use of some extraction solutions did not yield reliable results in the case of particular plants. It was found in this study that the extraction solution Mehlich 3 is suitable for determining the fertiliser requirement of the soils of Estonia, considering their diverse agrochemical properties, while it allows to reduce the number of the extraction solutions. Also, employment of the extraction solution Mehlich 3 yielded more reliable results with respect to plants in the case of phosphorus, potassium, copper and, particularly, magnesium and manganese. Key words: fertiliser requirement, available phosphorus, potassium, calcium, magnesium, copper, manganese, double lactate extraction, ammonium lactate extraction, 1 N HCl extraction, 1 N (NH₄)₂SO₄ extraction, Mehlich 3 extraction

Assessment of the agrochemical properties of the soil using the extraction solution Mehlich 3 in Estonia

V. Loide¹, M. Nõges² and J. Rebane²

¹Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: valli.loide@mail.ee
²Agricutural Research Centre, Teaduse 4/6, 75 501 Saku, Estonia; e-mail: noges@pmk.agri.ee

Abstract. To determine the requirement of macro- and microelements, seven extraction solutions have been employed in Estonian practice. Double lactate (DL) extraction has been used for determination of the phosphorus and potassium requirement, ammonium lactate (AL) extraction for determination of the calcium and magnesium requirement, and five more different extractions have been used for determination of microelements. Hence the need for a more appropriate extraction solution was due to the large number of the extraction solutions used until now, which made determination of the fertiliser requirement less efficient; also, in some cases, use of some extraction solutions did not yield reliable results in the case of particular plants. It was found in this study that the extraction solution Mehlich 3 is suitable for determining the fertiliser requirement of the soils of Estonia, considering their diverse agrochemical properties, while it allows to reduce the number of the extraction solutions. Also, employment of the extraction solution Mehlich 3 yielded more reliable results with respect to plants in the case of phosphorus, potassium, copper and, particularly, magnesium and manganese.

Key words: fertiliser requirement, available phosphorus, potassium, calcium, magnesium, copper, manganese, double lactate extraction, ammonium lactate extraction, 1 N HCl extraction, 1 N (NH₄)₂SO₄ extraction, Mehlich 3 extraction

Profitability of grain and rapeseed production in Estonia: future prospects V. Loko, E. Koik and K. Tamm Department of Mechanisation, Estonian Research Institute of Agriculture, Teaduse 13, 75501 Saku, Estonia; e-mail: valdek.loko@mail.ee, enno.koik@mail.ee, kalvi.tamm@neti.ee Abstract. The accession of Estonia to the EU and the introduction of the Common Agricultural Policy (CAP) will increase the country’s agricultural income substantially. Nevertheless, because of the northern climatic conditions, profitability of grain and rapeseed production in Estonia may have more problems than in other EU member states. The future impact of the CAP reform on grain production is being discussed. Results of different research projects are compared and the Estonian situation is analysed. It seems that there will be incentives for producers to decrease grain area in Estonia. Economic comparison was made about three tillage and sowing technologies: direct drilling, minimum and conventional tillage. Calculation results show that direct drilling and minimum tillage give better results than conventional tillage. However, the impact of direct drilling on yield and profit is more questionable and needs further research and farming experience. During last years, rapeseed production has increased because of its higher profitability than grain production. Possible future WTO negotiation results may also create problems in Estonian agriculture because of the northern climatic conditions. Key words: profitability of grain and rapeseed production, CAP reform impact on grain production, direct drilling, minimum tillage, conventional tillage, WTO negotiations

Profitability of grain and rapeseed production in Estonia: future prospects

V. Loko, E. Koik and K. Tamm

Department of Mechanisation, Estonian Research Institute of Agriculture, Teaduse 13, 75501 Saku, Estonia; e-mail: valdek.loko@mail.ee, enno.koik@mail.ee, kalvi.tamm@neti.ee

Abstract. The accession of Estonia to the EU and the introduction of the Common Agricultural Policy (CAP) will increase the country’s agricultural income substantially. Nevertheless, because of the northern climatic conditions, profitability of grain and rapeseed production in Estonia may have more problems than in other EU member states. The future impact of the CAP reform on grain production is being discussed. Results of different research projects are compared and the Estonian situation is analysed. It seems that there will be incentives for producers to decrease grain area in Estonia. Economic comparison was made about three tillage and sowing technologies: direct drilling, minimum and conventional tillage. Calculation results show that direct drilling and minimum tillage give better results than conventional tillage. However, the impact of direct drilling on yield and profit is more questionable and needs further research and farming experience. During last years, rapeseed production has increased because of its higher profitability than grain production.
Possible future WTO negotiation results may also create problems in Estonian agriculture because of the northern climatic conditions.

Key words: profitability of grain and rapeseed production, CAP reform impact on grain production, direct drilling, minimum tillage, conventional tillage, WTO negotiations

Effect of stubble breaking and ploughing at different depths on cultivation of peas K. Pranaitis and S. Marcinkonis Voke branch of the Lithuanian Institute of Agriculture, Žalioji aikštė 2, Trakų Vokė, LT-02232 Vilnius; e-mail: kestas.pranaitis@voke.lzi.lt Abstract. Field trials were conducted over the period 1998–2001 at the Voke Branch of the Lithuanian Institute of Agriculture on a sandy loam Haplic Luvisol (LVh). Pea’s precrop was winter rye. Crop residues were returned to the soil; straw was chopped at harvest. The aim of the investigation was to determine the effect of stubble breaking, ploughing at different depths on the weediness of cultivated crop, as well as on the crop yield. Most couch-grass (Elytrigia repens (L.) Nevski) infested were unbroken-stubble and shallow-ploughed plots. It caused a yield reduction by 11–20%. The lowest numbers of weeds were counted and the highest pea’s yield was obtained on broken stubble, 0.22–0.25 m depth ploughed. Key words: stubble breaking, ploughing, straw, peas, weed infestation, yield

Effect of stubble breaking and ploughing at different depths on cultivation of peas

K. Pranaitis and S. Marcinkonis

Voke branch of the Lithuanian Institute of Agriculture, Žalioji aikštė 2, Trakų Vokė,
LT-02232 Vilnius; e-mail: kestas.pranaitis@voke.lzi.lt

Abstract. Field trials were conducted over the period 1998–2001 at the Voke Branch of the Lithuanian Institute of Agriculture on a sandy loam Haplic Luvisol (LVh). Pea’s precrop was winter rye. Crop residues were returned to the soil; straw was chopped at harvest. The aim of the investigation was to determine the effect of stubble breaking, ploughing at different depths on the weediness of cultivated crop, as well as on the crop yield.

Most couch-grass (Elytrigia repens (L.) Nevski) infested were unbroken-stubble and shallow-ploughed plots. It caused a yield reduction by 11–20%. The lowest numbers of weeds were counted and the highest pea’s yield was obtained on broken stubble, 0.22–0.25 m depth ploughed.

Key words: stubble breaking, ploughing, straw, peas, weed infestation, yield

Some biochemical aspects of Fragi-Stagnic Albeluvisols’ organic matter L. Szajdak¹, P. Kuldkepp², E. Leedu², T. Teesalu², A. Toomsoo² and R. Kõlli^2* ¹Research Centre for Agricultural and Forest Environment, Polish Academy of Sciences, ul. Bukowska 19, 60-809 Poznań, Poland; e-mail: szajlech@man.poznan.pl ²Institute of Agricultural and Environmental Sciences, Estonian Agricultural University, Kreutzwaldi 64, 54014 Tartu, Estonia; e-mail: raimo@eau.ee *Author for correspondence Abstract. The concentrations of N-NH₄⁺, N-NO₃^-, N_total, total (TOC) and water extractable (DOC) organic carbon, P, K, Ca, Mg, S, the activity of nitrate reductase, the activity of urease activity as well as indole-3-acetic acid (IAA) were investigated in Fragi-Stagnic Albeluvisols’ organic matter under different organic and mineral fertiliser regimes from a long-term soil formation of a field experiment with three-field crop rotation (potato – spring wheat – spring barley) at Eerika near Tartu, Estonia, and also in the forest of Tiksoja. The concentrations of N_total, IAA, the activity of urease and also C/N ratios were generally highest in the forest soil of Tiksoja. Consequently, characteristics, distributions and conversions in organic matter were found in the proportions of chemical and biochemical factors, particularly after mineral and organic fertilisers. The following kinds of fertilisers increased the activity of urease in the order: WOM/N-120 < FYM/N-120 < RS/N-120 (accordingly, WOM – without organic manure, FYM – farmyard manure, RS – recultivation substance), and increased the activity of nitrate reductase: WOM/N-120 > RS/N-120 > FYM/N-120. The highest increase of IAA was determined in the soil fertilised with RS/N-120. The experiment was characterised by the highest activity of urease, and the highest increase of IAA and also TOC in soils fertilised with RS/N-120. The various fertiliser regimes were different both for their biochemical factors as well as the crop yields. WOM/N-120 as a mineral fertiliser and RS/N-120 as an organic one revealed the highest crop yield of potato, spring wheat, and spring barley. Key words: Albeluvisols, organic matter, long-term field experiment, organic and mineral fertilisation, urease and nitrate reductase, auxine, crop yields

Some biochemical aspects of Fragi-Stagnic Albeluvisols’ organic matter

L. Szajdak¹, P. Kuldkepp², E. Leedu², T. Teesalu², A. Toomsoo² and R. Kõlli^2*

¹Research Centre for Agricultural and Forest Environment, Polish Academy of Sciences, ul. Bukowska 19, 60-809 Poznań, Poland; e-mail: szajlech@man.poznan.pl
²Institute of Agricultural and Environmental Sciences, Estonian Agricultural University, Kreutzwaldi 64, 54014 Tartu, Estonia; e-mail: raimo@eau.ee
*Author for correspondence

Abstract. The concentrations of N-NH₄⁺, N-NO₃^-, N_total, total (TOC) and water extractable (DOC) organic carbon, P, K, Ca, Mg, S, the activity of nitrate reductase, the activity of urease activity as well as indole-3-acetic acid (IAA) were investigated in Fragi-Stagnic Albeluvisols’ organic matter under different organic and mineral fertiliser regimes from a long-term soil formation of a field experiment with three-field crop rotation (potato – spring wheat – spring barley) at Eerika near Tartu, Estonia, and also in the forest of Tiksoja. The concentrations of N_total, IAA, the activity of urease and also C/N ratios were generally highest in the forest soil of Tiksoja.
Consequently, characteristics, distributions and conversions in organic matter were found in the proportions of chemical and biochemical factors, particularly after mineral and organic fertilisers. The following kinds of fertilisers increased the activity of urease in the order: WOM/N-120 < FYM/N-120 < RS/N-120 (accordingly, WOM – without organic manure, FYM – farmyard manure, RS – recultivation substance), and increased the activity of nitrate reductase: WOM/N-120 > RS/N-120 > FYM/N-120. The highest increase of IAA was determined in the soil fertilised with RS/N-120.
The experiment was characterised by the highest activity of urease, and the highest increase of IAA and also TOC in soils fertilised with RS/N-120. The various fertiliser regimes were different both for their biochemical factors as well as the crop yields. WOM/N-120 as a mineral fertiliser and RS/N-120 as an organic one revealed the highest crop yield of potato, spring wheat, and spring barley.

Key words: Albeluvisols, organic matter, long-term field experiment, organic and mineral fertilisation, urease and nitrate reductase, auxine, crop yields

Expedience of differentiation of the value added tax rate imposed on foodstuffs in Estonia P. Zeiger, J. Lehtsaar and Ü. Kerner Institute of Economics and Social Sciences, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: zeiger@eau.ee Abstract. Changing the principles of imposing income tax and cutting down the rate of value added tax imposed on food has been discussed in Estonia during the last years. The possible impact of reduction of the value added tax rate, imposed on foodstuffs, on the disposable income of Estonian households was analysed for the period 2002-2003. Households were distributed into five income groups, and the effect arising from discussed changes in the value added tax was calculated for all income groups. In order to compare it with the result of VAT differentiation, the impact of linking of the basic exemption rate and gross minimum wages to the income of households was analysed as well. Due to the insignificant impact on the disposable income of households, a proposal to reduce the rate of value added tax imposed on food is not well-grounded and there is no justified need to drop it from current 18% to 5%. Key words: value added tax, households’ income, saving

Expedience of differentiation of the value added tax rate imposed on foodstuffs in Estonia

P. Zeiger, J. Lehtsaar and Ü. Kerner

Institute of Economics and Social Sciences, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: zeiger@eau.ee

Abstract. Changing the principles of imposing income tax and cutting down the rate of value added tax imposed on food has been discussed in Estonia during the last years. The possible impact of reduction of the value added tax rate, imposed on foodstuffs, on the disposable income of Estonian households was analysed for the period 2002-2003. Households were distributed into five income groups, and the effect arising from discussed changes in the value added tax was calculated for all income groups. In order to compare it with the result of VAT differentiation, the impact of linking of the basic exemption rate and gross minimum wages to the income of households was analysed as well. Due to the insignificant impact on the disposable income of households, a proposal to reduce the rate of value added tax imposed on food is not well-grounded and there is no justified need to drop it from current 18% to 5%.

Key words: value added tax, households’ income, saving