Andmebaasi logo

Sirvi Autor "Madsen, Helena" järgi

Nüüd näidatakse 1 - 4 4
  • 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
    Erinevate taimeliikide püsivus taimikus ning tolmeldajate meelistaimed seemnesegude võrdluses
    (Eesti Maaülikool; Maaelu Teadmuskeskus, 2026) Madsen, Helena; Talgre, Liina; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut. Taimekasvatuse õppetool
    An experiment with five different seed mixtures was established in the Rannu Seeme OÜ field with the aim of analyzing the competitiveness and durability of the sown species and assessing the suitability of the flowering plants in the mixtures as honey plants for bees and other pollinators. Evaluation of the flowering of seed mixtures and observation of pollinators took place consistently throughout the vegetation period in 2024–2025. The results were variable, as weather conditions affected the germination and flowering of the plants in the seed mixtures. The very species-rich Lebensraum and Veitshöchheimer mixtures contained less than half of the sown species in the plant biomass, but they had better weed suppression. The highest weed content was found with only one sown species, Onobrychis viciifolia, in the Sweden field. Pollinator observations were unpredictable in terms of their behaviour, but it was possible to conclude that there were more pollinators in the Lebensraum and Veitshöchheimer field sections until the plants reached full bloom, after which the flora became too dense and could have become an obstacle for pollinators.
  • Pisipilt
    Kirje
    Umbrohtude biomassi, arvukuse ja mitmekesisuse muutused pikaajalise külvikorra katse teises rotatsioonis
    (Estonian Academic Agricultural Society, 2023) Madsen, Helena; Luik, Anne; Eremeev, Viacheslav; Mäeorg, Erkki; Talgre, Liina; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut
    The effects of long term (established in 2008) five-field crop rotation (barley (Hordeum vulgare L.) with undersown red clover (Trifoium pratense L.), red clover, winter wheat (Triticum aestivum L.), pea (Pisum sativum L.), potato (Solanum tuberosum L.)) on the biomass, abundance and diversity (Shannon-Wiener index) of weeds in three organic (Org) and two conventional (Conv) systems after the second rotation were investigated. The results include data from the second rotation in 2013 – 2017. The control system (Org 0) followed only the crop rotation. In the organic systems Org I and Org II winter cover crops were used. In Org II system composted cattle manure was also applied. The conventional cropping systems were treated with herbicides and fungicides and system Conv 0 acted as control (no fertilizer use). Mineral fertilizer was used in Conv II. In general, the significant differences were evident between conventional and organic cropping systems. There were also some differences depending on the crop. The weed biomass was the lowest in barley and potato plots, with significantly higher values in organic than in conventional systems. In clover plots the highest biomass of weeds occurred in Conv II whilst the lowest in Org I. In winter wheat plots the biomass of weeds was significantly lower in conventional systems than in any of the organic systems. Pea plots had the highest biomass, abundance and diversity of weeds in all systems within all rotational crops. Slight tendencies showed the decrease of weed abundance and diversity at the end of the rotation in systems with cover crops (Org I and Org II). This could be explained by better growing conditions due to higher microbial activity and organic carbon content in the soil of organic systems.
  • Pisipilt
    Kirje
    Weeds in different cropping systems
    (Estonian University of Life Sciences, 2025) Madsen, Helena; Talgre, Liina (advisor); Luik, Anne (advisor); Institute of Agricultural and Environmental Sciences; Romaneckas, Kęstutis (opponent)
    ABSTRACT. Weeds play multiple roles in an agroecosystem. On the one hand they compete with crops for water and nutrients and on the other hand they enhance biodiversity within the field community, thereby providing environmental benefits. The aim of this study was to investigate weed occurrence in a long-term crop rotation experiment. The five-field rotation (barley undersown with clover, clover, winter wheat, pea, potato) was conducted under five different cropping systems. In two conventional systems herbicides were used for weed control, one of them also used mineral fertilizers. One organic system followed the crop rotation as a control variant. The remaining two systems used winter cover crops; composted manure was additionally applied to one of the systems. Weed occurrence and species composition depended on both the cropping system and the crop. In the first rotation the study of weed seedbank in the soil revealed that the number of weed seeds in organic cropping remained at a similar level compared to conventional systems, but species diversity was higher in organic systems. The highest number of weed seeds was found in the soil of pea fields across all systems except in organic system with winter cover crops. The lowest seed count was found in the soil of barley undersown with clover fields in conventional system with mineral fertilizers and in organic system with manure. In the second rotation, studies showed that weed biomass and density of occurrence was increased in all cropping systems, but significantly more in organic systems than in conventional ones. Also, weed diversity increased more in organic systems, being highest in the organic system with winter cover crops. Among the crops, weed biomass and density were high in pea and low in barley. Among the winter cover crops winter rye suppressed weeds most. However, likely due to their low biomass, winter cover crops did not achieve weed suppression comparable to herbicides. Nevertheless, winter cover crops improved soil properties and had a yield-enhancing effect.