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Poisa L.,Latvia University of Agriculture | Bumane S.,Latvian Plant Protection Research Center | Cubars E.,Rezekne Technologies Academy | Antipova L.,Mykolayiv State Agrarian University
Engineering for Rural Development | Year: 2016

The aim of the research - to evaluate the nitrogen fertilizer rate impact on the energetic parameters of hemp. The nitrogen fertilizer rate effect on the hemp ash content depends on the hemp variety: for the local variety "Purini", with the increase of the nitrogen fertilizer rate, the ash content decreases, while for the variety "Bialobrzskie" - it is the opposite - increasing the nitrogen fertilizer rate, the ash content increases. Change of the nitrogen fertilizer rate from N0 to N100 increased the resulting thermal capacity from one hectare. In this research it was observed that a higher thermal capacity has a positive (p < 0.001) connection with the harvest yield amount. For the sown hemp the nitrogen rate variation increased the thermal energy amount from one hectare for shives by 73 % ("Pūriņi") and 31 % ("Bialobrzskie"), for the stalks by 66 % ("Pūriņi") and 36 % ("Bialobrzskie"). The highest determined thermal capacity for hemp was 171.71 ± 18.31 GJ·ha-1.


Rancane R.,Latvia University of Agriculture | Rancane R.,Latvian Plant Protection Research Center | Vilka L.,Latvia University of Agriculture | Vilka L.,Latvian Plant Protection Research Center | Bankina B.,Latvia University of Agriculture
Research for Rural Development | Year: 2013

Several fungicide applications are used to control a pear scab (Venturia pirina Aderh.) on pear (Pyrus communis L.) trees. Minimal chemicals use in fruit-growing constantly has been important condition in the integrated fruit production; therefore, sanitation is recommended to reduce a primary inoculum in orchards. The study was carried out in an integrated pear orchard located in Sigulda district, in the central part of Latvia to estimate if a fall treatment of a pear orchard with urea reduces an amount of pseudothecia and pear scab incidence level the following season. Six treatments trial was arranged in the autumn 2011 on a moderately susceptible pear cultivar 'Belorusskaya Pozdnaya'. An amount of leaf litter, pseudothecia and incidence level of a disease on leaves and fruits were determined. The results showed that urea application reduced both an amount of leaf litter and a number of pseudothecia. An average amount of leaf litter was 127 leaves per 0.25 m2 in a control and 89 leaves in a treatment with urea application. The number of pseudothecia reached 250 pseudothecia per one leaf disc in a control and 160 pseudothecia in a treatment with the urea application, the difference was not significant (p>0.05). The reduction of disease incidence level on leaves was significant (p<0.05) only in the first assessment of five in total.


Bumane S.,Latvian Plant Protection Research Center | Platace R.,Latvia University of Agriculture | Poisa L.,Latvia University of Agriculture | Adamovics A.,Latvia University of Agriculture
Engineering for Rural Development | Year: 2016

The aim of the research is to establish the chemical content of reed canary grass and their (C, S (SO2, SO3), Na, K) interconnection. Apart from this, there is a large role for environment - friendly growing technologies, which should guarantee qualitative soil tillage, suitable variety cultivation and the use of fertilizers according to the agrochemical parameters. In order to assess the suitability of the varieties of reed canary grass plants for energy production with the combustion process there were made the analysis of the chemical content in plants and factors (different N fertilizer rate) affecting it using canary reed grass. Field trial was carried out during 2011-2012. Carbon content for reed canary grass varieties "Bamse" and "Marathon" is by approximately one percent greater than for the variety "Pedja". On average the carbon content was within the range 46-48 %, depending on the fertilizer rates and variety. As the phosphorus content increases in the energy plants, the potassium content increases, which is the main alkali element. For the reed canary grass variety "Pedja" a significant positive correlation between the phosphorus and sulfur content was found.


Platace R.,Latvia University of Agriculture | Adamovics A.,Latvia University of Agriculture | Poisa L.,Latvia University of Agriculture | Cubars E.,Rezekne Higher Education Institute | Bumane S.,Latvian Plant Protection Research Center
Engineering for Rural Development | Year: 2015

One of the solutions for growing energy problems may be use of biomass; however heat production requires plants with particular characteristics. One of the biomass sources used for pellet production may be grass, nevertheless, it is a potential for high ash content leading to problems in the combustion process. Total ash content in grass biomass ranges between 2 % and 20 %. Research aims at measuring and characterising ash content in grass biomass yielded in 1st and 2nd cultivation year depending on the types and doses of fertilisers applied. It was found that the ash content in reed canary grass and tall fescue reduced (by 6.2 % and 6.7 %) and in festulolium, timothy and meadow fescue it increased (by 6.6 %, 6.7 % and 6.4 %). The data acquired show that grass biomass has high ash content; therefore it would be useful to produce pellets when mixing it with wood. High and high-quality grass yield requires application of nitrogen fertilisers, as they are among the key nutrients. In the research, average nitrogen content in tall fescue biomass dropped by 0.3 %, but it grew in biomass of reed canary grass (0.6 %), festulolium and timothy (0.5 %), meadow fescue (1.8 %).


Tan spot (caused by Pyrenophora tritici-repentis, anamorph Drechslera tritici-repentis) is one of the most important wheat leaf diseases all over the world, especially in the regions of intensive wheat growing. Tan spot was noticed and identified in Latvia and Lithuania in the first half of the 1990s when an increase in wheat proportion in a crop rotation caused rapid spread of the disease. In some cases, the incidence of tan spot approached 100% and severity reached 70% in Lithuania and Latvia. The paper gives a review of the literature by different authors, but mainly focuses on the research carried out in Latvia and Lithuania.


Grantina-Ievina L.,Latvian Plant Protection Research Center | Grantina-Ievina L.,University of Latvia | Ievinsh G.,Latvian Plant Protection Research Center | Ievinsh G.,University of Latvia
Research for Rural Development | Year: 2015

There is an increasing demand in the development of new and better types of organic plant fertilizers. The aim of the present study was to evaluate if the beneficial effect of vermicompost on plant growth and development could be further promoted by adding different amounts of bat guano using two model species under controlled conditions, as well as to assess the microbiological characteristics of bat guano and soil after its application. The study was performed at the Faculty of Biology, University of Latvia, during 2013 and 2014. The amount of bacteria was significantly lower in guano in comparison to vermicompost samples. No actinobacteria were present, but yeasts were found in the guano sample. Soil fungal populations after the application of organic fertilizer from vermicompost and bat guano were dominated by potentially plant growth promoting fungi Trichoderma and Mortierella. However, at increased guano concentration (300 g kg-1) the proportion of potentially plant pathogenic fungi significantly increased. Addition of bat guano to vermicompost fertilizer significantly enhanced the positive effect of the fertilizer on growth and development of winter rye (Secale cereale L.) and potato (Solanum tuberosum L.) plants.


Treikale O.,Latvian Plant Protection Research Center
Communications in agricultural and applied biological sciences | Year: 2010

Fusarium head blight (FHB) of wheat has, in recent years, been a very important worldwide disease in intensive growing of cereal. The objectives of this study were to evaluate the occurrence of FHB in wheat in Latvia and to identify the Fusarium species involved. This paper describes the distribution of Fusarium species that were isolated from samples representing winter and spring wheat varieties in Latvia, identified both by the classical morphological analyses of J. Leslie and B. Summerell (2006) and by PCR. The FHB incidence range in winter wheat was 1-20%, in spring wheat was 1-42%. The most significant factor affecting the incidence of fusarial head blight in wheat in Latvia was heightened temperature at the time of an thesis of wheat. In winter wheat 9 Fusarium species caused FHB: F. culmorum, F. avenaceum, F. graminearum, F. equiseti, F. poae, F. oxysporum, F. cerealis, F. sporotrichoides and F. verticillioides were identified by morphological characterization, and 5 were confirmed by PCR-analysis. After experience of 5 years, it can be concluded that the most frequent in winter wheat were F. poae and F. culmorum. In spring wheat from F. culmorum was dominant among 8 Fusarium species. Among 13 varieties of spring wheat, three were sensitive ('Chamsin', 'W 166', 'Azurite') and one was resistant ('Granny') to FHB in conditions of high natural infection in 2009. The monitoring surveys demonstrate a significant presence of FHB in spring wheat in conditions of heightened temperature at the time of flowering in Latvia.


Vanaga I.,Latvian Plant Protection Research Center
Communications in agricultural and applied biological sciences | Year: 2010

The composition of weed species in spring barley and weed biodiversity was evaluated in experiments in different growing seasons and with different previous crops. The aim of the experiments was to evaluate the composition of weed species in spring barley during a four year period in weather conditions of different growing seasons and with different previous crop as well as to assess the biodiversity in the experiments where the different groups of herbicides were applied. Over years and previous crops, the dicotyledonous weed community was dominated by Chenopodium album, followed by Viola arvensis. The herbicides from different groups had significant influences on the biodiversity of weeds.


Vanaga I.,Latvian Plant Protection Research Center
Communications in agricultural and applied biological sciences | Year: 2012

Dicot weed populations were assessed in spring barley trials carried out in four three-years periods at 5-year intervals: 1990-1992, 1995-1997; 2001-2003 and 2006-2008. The overall aim of this research was to evaluate the changes in dicot-weed infestations in spring barley in fields of one region (Riga) of Latvia in sod-podzolic loamy sand soil. The results of the trials showed that Galeopsis spp, Stellaoria media, Viola orvensis and Chenopodium album were among the most frequent weed species in the periods of 1990-1992 and 1995-1997. The occurrence of C. album and V. arvensis increased during the periods of 2001-2003 and 2006-2008.


Grantina-Ievina L.,Latvian Plant Protection Research Center | Stanke L.,Latvian Plant Protection Research Center | Ergle G.,Latvian Plant Protection Research Center
Vide. Tehnologija. Resursi - Environment, Technology, Resources | Year: 2015

The microbiological fertilizer Baikal EM-1 contains lactic acid bacteria, photosynthetic bacteria, nitrogen fixing bacteria, Saccharomyces yeasts and microbial cultivation media. The aim of the present study was to evaluate the impact of it on onion grown in controlled greenhouse conditions. In summer 2014 two trials with this product were carried out on onions in greenhouse conditions. Before planting onion bulbs were soaked in water with added fertilizer and growth substrate was watered with the fertilizer according to the instructions of manufacturer. During the vegetation period plants were watered with the fertilizer several times. Identical treatment was performed with water in the control plots. Different treatment schemes and growth substrates (neutralized peat and substrate for vegetables) were used in both trials. The main difference of the used substrates was in the content of mineral nutrients that was higher in the substrate for vegetables. In the second trial additional fertilization with ammonium nitrate was applied three times during the vegetation period. At the end of the trials the yield of onion leaves was estimated, as well as the length of leaves and their chlorophyll content was measured. At the first trial the obtained yield of onion leaves was increased by 6.4% and in the second by 8.2% due to treatment with Baikal EM-1 but these differences were not statistically significant in comparison to the control plots. In general, the fertilizer increased all other measured parameters as well, including average length of leaves by 4.6% and 1.3%, the chlorophyll content by 5.0% and 1.5%, in the first and second trial respectively, and percentage of onions developing leaves increased by 13.2% in the second trial. Only the last parameter showed statistically significant differences in comparison to the control. Additionally the growth of the onion was more even in the control treatment. In conclusion, the microbiological fertilizer Baikal EM-1 gave positive impact on onions in greenhouse conditions. © Rezekne Higher Education Institution (Rēzeknes Augstskola), Rezekne 2015.

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