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Loide V.,Estonian Crop Research Institute | Rani A.,EDK Laboratory of Limestone | Randma I.,EDK Laboratory of Limestone
Acta Agriculturae Scandinavica Section B: Soil and Plant Science | Year: 2014

The leaching of dissolved calcium (Ca) and magnesium (Mg) carbonates is the main cause for decalcination of soils. The efficiency of various limes in replacing the carbonates and stabilising the available Ca content depends on the dynamics of lime solubility. The latter depends on the material and the size of its particles: the finer the material, the sooner it will dissolve and leach. To reduce the leaching of the Ca into the soil and to stabilise the available Ca content, the particle-size distribution on the basis of the solubility of lime particles with different sizes was determined so that lime would dissolve equally in a balanced way during the anticipated time. While the solubility of limestone particles of different sizes was being assessed in distilled water, the pH of water was brought to 4.0 by adding potassium biphthalate C8H5O4K: it was discovered that the solubility dynamics of all the lime applied to the soil can be controlled by means of its particle-size distribution. In the field trial, the soil contained the available Ca after the application of limestone (particle-size distribution: <0.16 mm 7%, <0.5 mm 25%, <2 mm 76% and <4 mm 93%) both at the beginning of the trial and in its third to fourth year at an equal and optimum level for the growth of field crops (1.50 g kg-1, with the base saturation around 80%). Considering the importance of Ca in soil and the leaching of a notable part of it, it is possible, by means of regulating the limestone solubility dynamics by the particle-size distribution, to improve the resistance of limes to leaching and erosion and to stabilise the Ca content in soil. © 2014 © 2014 Taylor & Francis. Source


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 Source


Runno-Paurson E.,Estonian University of Life Sciences | Hannukkala A.,Mtt Agrifood Research Finland | Kotkas K.,EVIKA of Estonian Crop Research Institute | Koppel M.,Estonian Crop Research Institute | And 2 more authors.
Journal of Plant Pathology | Year: 2014

In Estonia and Finland, 386 and 671 isolates, respectively, of Phytophthora infestans were collected during the growing seasons of 2001-2007. Collection was from groups of potato cultivars of different origin from field plots at two research institutions in eastern and northern Estonia and from variety trials at two locations and commercial potato fields in Finland. Mating type, pathotype based on virulence on a differential set of 11 R genes of Solanum demissum and response to the fungicide metalaxyl were determined in both countries by comparable methods. The diversity of the P. infestans populations in both countries over the monitoring period was high. In Finland, the proportion of A1/A2 mating types was almost equal throughout the monitoring period, while in Estonia the A1 population, dominating in 2001-2004, shifted towards an equal proportion of both mating types in 2005-2007. The diversity of the P. infestans population, as measured by virulence pathotypes and the number of avirulence factors per isolate, developed in opposite directions in Estonia and Finland from 2001-2004 to 2005-2007: the diversity decreased in Estonia and increased in Finland. Metalaxyl sensitivity in the Estonian P. infestans population increased while in Finland it decreased during the same period. Results clearly show differences between Estonian and Finnish populations of P. infestans in several aspects, which may derive from cropping practices. The high A2 mating type percentage during 2005-2007 in both countries points to soil contamination with oospores. Source


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. Source


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. Source

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