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Saue T.,Tallinn University of Technology | Saue T.,Estonian Crop Research Institute
International Journal of Biometeorology | Year: 2015

Wind chill equivalent temperature (WCET) is used to define thermal discomfort in winter months. Directional distributions of winds, which are associated with uncomfortable weather, were composed of three climatologically different Estonian locations: Vilsandi, Kuusiku, and Jõhvi. Cases with wind chill equivalent temperature <−10 °C, which could be classified as “uncomfortable or worse,” were investigated. Additional thresholds were used to measure weather risk. The 25th percentile of daily minimum WCET was tested to measure classical prevalent wind directions in Estonia: W, SW, and NW bring warm air in winter from the North Atlantic, while winds from the East-European plain (NE, E, and SE) are associated with cold air. The eastern prevalence was stronger when a lower threshold was used. A directional approach may find several applications, such as building, agricultural, landscape, or settlement planning. © 2015 ISB


Saue T.,Estonian Crop Research Institute | Saue T.,Tallinn University of Technology | Kadaja J.,Estonian Crop Research Institute
Agricultural and Forest Meteorology | Year: 2014

Soil moisture is one the most limiting factors for crop production. In temperate climates yields are reduced by both water deficit and excess. To calculate the impact of water limitations, alternative water balance schemes were added to the potato production model POMOD (POtato MODel) to keep the soil moisture content within its optimal range. The effects of irrigation, drainage and both together were investigated. Calculations were carried out for three Estonian locations (Tallinn, Tartu and Kuressaare) and two varieties. For the reference run the yields were higher for the late variety and lowest in dry Kuressaare. The average irrigation requirement was 30-45. mm for the early and 47-58. mm for the late variety in continental locations, but over two times higher in insular Kuressaare. In continental stations the need for drainage was 30-40. mm per growing period in addition to natural outflow (about 20-25. mm more without outflow). In Kuressaare the mean amount of excess precipitation was only 9-20. mm and its removal had a mostly negative effect on yield due to increasing water deficit during the following dry period. In over half of the years the crops suffered from both water shortage and excess. The greatest increase in yield was achieved when both drainage and irrigation were applied. The benefit from irrigation alone was also considerable, more for the late variety and in Kuressaare. The effect of drainage was most evident in conditions of restricted outflow The negative effects of drainage on yield, as observed in years when drainage led to increasing water deficit in subsequent periods, lowered the average impact of drainage. However, in some cases the highest yield losses were observed in years with excess water. © 2014 Elsevier B.V.


Kadaja J.,Estonian Crop Research Institute | Saue T.,Estonian Crop Research Institute | Saue T.,Tallinn University of Technology
Agricultural Water Management | Year: 2016

To examine the potential effect of water management on potato yields, the crop model POMOD (POtato MODel) was used. The effects of irrigation, drainage and two-way water management (irrigation + drainage) were simulated with and without natural outflow (percolation to deeper soil layers and runoff). Calculations were performed for two Estonian mainland locations (subcontinental Tallinn for the period 1920-2011, continental Tartu, 1901-2011) and one insular, maritime region (Kuressaare, 1923-2011) as well as for an early and a late potato variety, 'Maret' and 'Anti', accordingly.In the reference series without water management, the average yields were 18% higher for the late variety compared to the early variety. The mean reference yield in Kuressaare was 8% lower than in mainland locations. The mean water productivity (WP) calculated per evapotranspiration was nearly 45 kg mm-1 ha-1 (dry mass), somewhat higher for the late variety compared to the early variety. The highest and most statistically significant (P<0.05) increase of yield was achieved from the two-way water management. In the case of natural outflow (water losses to deep percolation and runoff exist), the effect of irrigation prevailed over drainage in all locations. Without outflow, the effects of irrigation and drainage were comparable in the mainland, but the effect of drainage remained negative in Kuressaare. Generally, a positive effect on tuber yield occurred more often from irrigation than from drainage. However, in the case of restricted outflow in the mainland locations, the maximum yield gain from drainage exceeded the yield increase from irrigation by approximately two-fold. The extra yield depended on the amounts of irrigation or drainage by a second order polynomial, while the productivity of irrigated or drained water was, on average, markedly lower than the WP calculated per evapotranspiration, which had a linear relation. Irrigation and drainage water amounts under 50 mm did not have any positive effect on yield.The need for irrigation is highest in maritime climate covering Estonian islands and Western and Northwestern coast. In these regions, irrigation increases the mean yield by 18-26% and decreases its variability two-fold. In continental locations, if natural outflow is restricted, implementation of two-way water management projects should be considered, as its effects on yield quantity as well as on stability exceed the sum of separate effects from irrigation and drainage. © 2015 Elsevier B.V.


Silicon (Si) is not an essential element for plant growth but considered as beneficial for the growth and development of most plants. The objective of this investigation was to investigate the effect of an extra supply of Si with foliar applied finely dispersed SiO2 • n H2O (= silicic acid “dissolved” in water) on early growth and elemental composition of tomato transplants. Silicic acid was applied as an aqueous spray applied in different concentrations from the first true leaf stage three times at two-week intervals in total 108 g/ha Si. Tomato transplants were taller with larger stem diameters when treateted with Si and NO3, N, P, K and Ca concentrations enhanced. © 2016, Verlag Eugen Ulmer. All rights reserved.


Silicon (Si) is the second most abundant element after oxygen in soil. However, many field studies have shown that supplying crops with extra Si in form of finely dispersed SiO2 · n H2O (= silicic acid “dissolved” in water) suppresses plant disease, reduces insect attack, improves environmental stress tolerance, and increases crop productivity. * The purpose of this investigation was to look at the influence of foliar applied silicic acid on the chemical content of field peas of variety Mehis. Silicic acid was applied as an aqueous spray applied in different concentrations from the 2–3 true leaf stage at two-week intervals from 21 May to 2 July 2014, in total 108 g ha–1 Si. Silicic acid partially improved the quality of field peas of variety Mehis by increasing phosphorus and potassium concentrations in the peas. It is suggested that foliar applied silicic acid may improve root growth through an improved phosphorus supply and also the water status of the plants through an improved potassium supply. © 2016, Verlag Eugen Ulmer.All rights reserved.


Jarvan M.,Estonian Crop Research Institute | Vettik R.,Estonian Crop Research Institute | Adamson A.,Estonian Crop Research Institute
Acta Agriculturae Scandinavica Section B: Soil and Plant Science | Year: 2016

The aim of this study was to investigate what kind changes in the soil fertility parameters occur depending on different farming methods. The field experiment was performed on sandy loam Luvisol during 2008–2014. The following treatments were carried out: organic (ORG), organic with farmyard cattle manure (ORGFYM) and conventional with farmyard cattle manure and mineral fertilizers (CONFYM). Soil samples were collected yearly in September and analyzed for P, K, Mg and Ca by the Mehlich III method. In parallel, ammonium lactate extractable P and K (AL method), and ammonium acetate extractable Mg and Ca (NH4OAc-method) were determined. The Pearson correlation coefficients between the analysis results achieved by the Mehlich III method and alternative methods were calculated. In all the treatments, no significant changes in soil Corg content were established over seven years. A significant (p < .05) decrease in soil pH was shown for the CONFYM treatment. Organic management without nutrients’ input does not decrease the content of PAL in the soil but considerable decrease in the soil KAL content was revealed. The application of cattle manure (60 t ha−1 for the 5-year crop rotation) in both organic and conventional treatments sustained the status of available nutrients in the soil. The Pearson correlation coefficients between Mehlich III and AL methods for P (r = 0.770, p < .01) were lower than for K (r = 0.922, p < .01). The highest correlation between Mehlich III and NH4OAc-methods was found in the case of Mg (r = 0.951, p < .01) whereat for Ca the correlation was somewhat weaker (r = 0.841, p < .01). It was also shown that the PMehlich III/PAL quotient was inversely proportional with the CaMehlich III values. © 2016 Informa UK Limited, trading as Taylor & Francis Group


Bender A.,Estonian Crop Research Institute | Tamm S.,Estonian Crop Research Institute
Research for Rural Development | Year: 2014

Field trials were carried out at Jõgeva Plant Breeding Institute in 2008 - 2011 to identify the possibilities of using early red clover (Trifolium pratense L.) 'Jõgeva 433' (diploid), Washington lupin (Lupinus polyphyllus Lind.) 'Lupi' and crimson clover (Trifolium incarnatum L.) as green manure. Fresh material of the above species was ploughed into the soil in autumn of the sowing year. Fertilizer value was quantified through yield and grain quality of spring wheat 'Vinjett' and barley 'Inari'. The composition and amount of ploughed biomass were recorded. By the time of ploughing, Washington lupin had produced the most abundant biomass. From studied species crimson clover had the lowest fertilizer value - only by 6-7% extra yield of spring wheat in the following year. Crimson clover had no residual effect of fertilization in the second year. The fertilizer values of red clover and Washington lupin were approximately equal. Their effect on yield increase of spring wheat and barley lasted for three years, on grain quality for two years. Red clover, ploughed into the soil in the year of sowing, resulted in maximum spring wheat yield increase of 23.9%, compared with N 0 treatments; that of Washington lupin was 21.3%. The residual positive effect in the second year quantified as barley production increased by 6.2% in Washington lupin and 7.9% in red clover. The yield increase in the third year was 3.9% and 12.1%, respectively. Green manure increased the contents of crude protein and gluten in spring wheat and crude protein content in barley.


The aim of the current research was to investigate the influence of organic and conventional farming on certain bacteria (nitrifiers, denitrifiers and azotobacteria) involved in the soil nitrogen cycle. During 2007–2013, field experiments were performed in Central-Estonia (58º33′ N, 25º34′ E) on a sandy loam Albeluvisol (AB) in a five-field crop rotation (winter rye → potato → oats → barley with undersowing → red clover). The following treatments were carried out: organic without manure, organic with cattle manure, and conventional where manure, mineral fertilizers and pesticides were used. In the treatments, solid cattle manure (60 t ha-1) was applied for potato. In 2007–2013, soil samples for microbiological tests were taken from the two fields of the crop rotation from 0–20 cm layer. All soil samples were examined for the total number of bacteria, azotobacteria, denitrifying and nitrifying bacteria using the plate-count method. In the organic farming, the application of cattle manure significantly (P < 0.05) increased the total bacteria communities. Also the nitrifying bacteria responded greatly to the soil nutritional status. Their abundance in the organic without manure treatment was significantly (P < 0.05) lower than that in the other treatments. There were no significant (P < 0.05) differences in the counts of denitrifying bacteria between the treatments. The repeated application of fungicides and insecticides for potato protection decreased the number of azotobacteria as direct effect by 2.7 times and had a harmful aftereffect on these sensitive bacteria also in succeeding years. © 2015, Lithuanian Institute of Agriculture. All rights reserved.


Bender I.,Estonian Crop Research Institute | Moor U.,Estonian University of Life Sciences | Luik A.,Estonian University of Life Sciences
Research for Rural Development | Year: 2015

The aim of the research was to evaluate how the quality of carrots is affected by organic and conventional production systems. The experiment was carried out at the Estonian Crop Research Institute in 2009. Conventional treatment received the following amount of nutrients via mineral fertilizers: N 115, P 40 and K 152 kg ha-1. For plant protection, the following pesticides were used: Fenix, Fastac 50, Agil and Signum. In organic cultivation system compost and humic acid solution Humistar were used for fertilization and polypropylene non-woven fabric Agryl P-17 for plant protection. Marketable yield of organic carrots was 8% lower compared to the conventional carrots. Conventional carrots contained pesticide residues and had significantly higher nitrate concentration than organic carrots. The contents of total sugars, phosphorus, potassium, calcium and magnesium did not differ significantly between carrots from different cultivation systems. At harvest, dry matter (DM) content of organically grown carrots was significantly higher, whereas vitamin C and β-carotene content was significantly lower in organically grown carrots. However, after 5-months of storage, the organic carrots had significantly higher total soluble solids (TSS) and β-carotene content compared to the conventional ones indicating that organically grown carrots were less susceptible to storage conditions.


Bender A.,Estonian Crop Research Institute | Tamm S.,Estonian Crop Research Institute
Research for Rural Development | Year: 2015

In Estonia, the most promising perennial grass used as raw material for production of heat energy is reed canarygrass (Phalaris arundinacea L.). Nordic countries (Finland, Sweden) implement a technology including single harvest of the above-ground biomass from frozen soil early in spring. This technology cannot be used in Estonia as the ground does not freeze to the extent of bearing harvesting machines every year. Harvesting in spring is virtually impossible as herbage lodges excessively under the snow weight. A divided harvesting method of reed canarygrass was tested in field trials in 2010-2013 at the Estonian Crop Research Institute. Herbages were cut in July at the height of 60-65 cm, mass was dried as hay, stubble hay was left to grow and was harvested next spring before the growth started but soil had become dry. The effect of seeding rate, row spacing and nitrogen fertilizer on the dry matter yield of reed canarygrass was investigated. The amount of produced heat by trial variants was calculated. The variant with narrow spacing (15 cm), seeding rate of 8 kg ha-1 and usage of fertilizer N70 in the beginning of growth and N70 kg ha-1 after the first cut was giving the best results. Two cuts of this variant yielded on average 8.12 t ha-1 per year, of which the stubble hay, harvested in spring and with better combustion properties, made 64%. Energetic value of the yield was 138 GJ ha-1 per year.

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