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Sirvi Autor "Toom, Merili" järgi

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  • Pisipilt
    Kirje
    The content of weed seeds in the soil based on the management system
    (2017) Kuht, Jaan; Eremeev, Viacheslav; Talgre, Liina; Madsen, Helena; Toom, Merili; Mäeorg, Erkki; Loit, Evelin; Luik, Anne; Estonian University of Life Sciences
    In 2008 an experiment was set up on the field in Eerika experimental station (Estonian University of Life Sciences) as a 5-field crop rotation: barley (Hordeum vulgare L.) with undersown red clover, red clover (Trifolium pratense L.), winter wheat (Triticum aestivum L.), pea (Pisum sativum L.), potato (Solanum tuberosum L.). The objective of the study was to measure the content of weed seeds in the soil and to evaluate the diversity of the species at the beginning of the period of organic production in 2011. In conventional farming systems without fertilizer (Con I) and conventional farming with mineral fertilizer (Con II) herbicides were used for weed control. All the crops in Con II system received P 25 kg ha-1 and K 95 kg ha-1 , but the application rates of mineral nitrogen fertilizer differed. In organic systems (Org I – organic farming based on winter cover crop and Org II – organic farming based on winter cover crop and manure), the winter cover crops (ryegrass after winter wheat, winter oilseed rape after pea, winter rye after potato) were sown after the harvest and were ploughed into the soil as green manure in spring. Organic farming systems (Org II) had a negative effect on the content of weed seeds in the soil (2.0–22.7% less seeds than in other variants). The seeds of Chenopodium album were the most abundant among summer annual weeds and the seeds of Viola arvensis among winter weeds in the soil. Organic farming measures increased the domination of Chenopodium album – the dominance index D’ was increased by 0.09–0.14 compared to conventional variants. The content of seeds of winter weed Viola arvensis in Org II variant was decreased by 82%. The index of species evenness J’ and Shannon Wiener diversity index H’ were lower in organic plots by 0.10– 0.18 and 0.60–0.19, respectively. Org II variants showed the best results based on the decrease of soil weed seed bank and distribution of the weed species.
  • Pisipilt
    Kirje
    The effect of cover crops on biomass and nitrogen accumulation and on crop yield
    (Eesti Maaülikool, 2021) Toom, Merili; Lauringson, Enn (advisor); Talgre, Liina (advisor); Mäe, Andres (advisor); Bogužas, Vaclovas (opponent)
    The aims of the thesis were to evaluate the biomass and N accumulation of winter cover crop species (winter rye, winter turnip rape, forage radish, berseem clover and hairy vetch), winter hardiness of hairy vetch, the effect of sowing date on biomass and N accumulation and the effect of CCs on the yield of subsequent spring barley. The results showed that CC biomass and N accumulation depended on species and growing conditions, especially the sum of effective temperatures. Frost sensitive forage radish accumulated the highest amount of biomass and N in autumn, whereas berseem clover accumulated low amount of biomass and N, especially in the year with drought conditions before the establishment. Hairy vetch over-wintered similarly to winter turnip rape and winter rye in all trial years. Hairy vetch and winter turnip rape accumulated higher amount of biomass and N in the spring than winter rye, which may be partly related to characteristics of the used winter rye variety. Cover crop biomass and N accumulation decreased with delayed sowing dates, while the influence of sowing date on cover crop species was different. Forage radish produced the highest amount of biomass and N at all sowing dates. Although the biomass of rye was relatively low, the reduction at delayed sowing dates was lowest compared to other species. Among over-wintering CCs, hairy vetch as a legume species accumulated the highest amount of N in the spring. It can be concluded that in Estonia, CCs require sowing in early August to enable maximum biomass and N accumulation. It is possible to delay the sowing of over-wintering species if the following cash crop is sown later. As an average over the three years, only forage radish and hairy vetch significantly increased the yield of subsequent barley, probably because of the N contribution. None of the CCs had negative effect on barley, as the yield level following winter turnip rape, winter rye, and berseem clover were similar to the control.
  • Pisipilt
    Kirje
    The effect of sowing date on cover crop biomass and nitrogen accumulation
    (2019) Toom, Merili; Talgre, Liina; Pechter, Priit; Narits, Lea; Tamm, Sirje; Lauringson, Enn; Estonian University of Life Sciences
    Cover crops are important tools for reducing nitrogen (N) leaching from the soil and improving the nutrition of cash crops. In northern regions with short autumns it is important to maximise the growing season of cover crops to achieve sufficient biomass and N accumulation. The objective of the study was to evaluate the biomass and N accumulation of cover crops at different sowing dates in August. Field experiment at Estonian Crop Research Institute was conducted in 2017 and 2018 with white mustard (Sinapis alba L.), phacelia (Phacelia tanacetifolia Benth), buckwheat (Fagopyrum esculentum Moench), berseem clover (Trifolium alexandrinum L.), field pea (Pisum sativum L.) and faba bean (Vicia faba L.). Cover crops were sown on August 3, 8, 14 and 18 in 2017 and August 3, 8, 13, 17 and 23 in 2018. The two year experiment showed that biomass and N accumulation of cover crops were reduced with delayed sowings, but the reduction mainly depended on cover crop species. White mustard, field pea and faba bean accumulated significantly higher amount of biomass and N than phacelia, buckwheat and berseem clover at all sowing dates in both years. Because of a rapid decrease in biomass, the optimum sowing time for phacelia and buckwheat should not be later than middle of August. In both year berseem clover produced the modest amount of biomass and therefore more suited as spring sown cover crop in Estonian conditions.
  • Pisipilt
    Kirje
    Kalatööstuse jääkidest biopõhised väetised: mõju saagile ja mullaelustikule
    (Eesti Maaülikool; Maaelu Teadmuskeskus, 2026) Edesi, Liina; Talve, Tiina; Kuu, Annely; Koll, Birgit; Roman, Ireene; Toom, Merili; Kärp, Merko; Tikk, Kristo; Võsa, Taavi; Oll, Mari; Jõgisoo, Grete; Bender, Ingrid; Karron, Elina; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut. Mullateaduse õppetool
    A field experiment was conducted in 2023 at the METK Jõgeva experimental site to evaluate the effects of biobased fertilizers derived from fishery waste and by-products on broccoli (Brassica oleracea var. italica) yield and soil biota in comparison with a synthetic mineral fertilizer. Four biobased fertilizers produced using different valorisation technologies were tested: bokashi pellets (BP), fish sludge pellets (KMP), a solid protein fraction (VF), and a liquid NPK solution enriched with amino acids (NPKA). The results showed that fertilizer treatment significantly affected total aboveground biomass yield, while broccoli head yield did not differ significantly among treatments. The highest biomass yield was obtained with the mineral fertilizer, followed by VF and NPKA, which performed comparably and demonstrated strong potential as alternatives to mineral fertilizers. Fish sludge pellets showed moderate effectiveness, whereas bokashi pellets resulted in lower yields, likely due to slow nitrogen release during early crop growth. Soil biological indicators responded sensitively to fertilizer type. Biobased fertilizers enhanced soil microbial activity compared with the mineral fertilizer, which tended to suppress microbial indicators. Short-term declines in the abundance of springtails and mites were observed following fertilization across all treatments, with partial recovery after harvest, indicating a transient response of soil mesofauna rather than a persistent negative effect. Overall, the findings demonstrate that biobased fertilizers derived from fishery by-products can maintain broccoli yield while supporting soil biological activity. These results highlight their potential as sustainable alternatives to synthetic mineral fertilizers and their contribution to circular nutrient management in organic and low-input agricultural systems.
  • Pisipilt
    Kirje
    Vahekultuuride biomassi moodustamise ja lämmastiku sidumise võime ning mõju suviodra saagile
    (Estonian Academic Agricultural Society, 2023) Toom, Merili; Talgre, Liina; Tamm, Sirje; Tamm, Ülle; Tamm, Ilmar; Narits, Lea; Talve, Tiina; Edesi, Liina; Lauringson, Enn; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut. Mullateaduse õppetool
    Cover crops play an important role in preventing nutrient loss, reducing agricultural inputs, improving soil quality and environmental sustainability. The objectives of the study were to determine the biomass and nitrogen accumulation of cover crops and their effect on the following spring barley (Hordeum vulgare L.). Field trials with cover crop species winter rye (Secale cereale L), winter turnip rape (Brassica rapa spp. oleifera L.), forage radish (Raphanus sativus L. var. longipinnatus), hairy vetch (Vicia villosa Roth), and berseem clover (Trifolium alexandrinum L.) were carried out during four growing seasons (2016/17, 2017/18, 2018/19, and 2019/20) at the Estonian Crop Research Institute (present: The Centre of Estonian Rural Research and Knowledge, METK). Cover crop biomass and N accumulation in autumn and in spring depended on species and growing conditions. The biomass and nitrogen (N) accumulation were at their lowest in the first growing season (2016/17) due to lowest level of effective temperatures. Forage radish accumulated the highest amount of biomass and N in autumn. Berseem clover accumulated lowest amount of biomass and N in the year with drought conditions (2018) before sowing. Among overwintered cover crops, hairy vetch accumulated the highest amount of N in the spring although its biomass was similar to winter turnip rape. Winter rye had the lowest biomass and N accumulation in spring. As an average over the four years, only forage radish and hairy vetch significantly increased the yield of subsequent barley. None of the cover crops had a negative effect on barley, as the yield level following other species was similar to the control without cover crop. The knowledge about cover crop selection is useful to integrate suitable species into Estonian cropping systems.