The spread of weeds and weed seed bank in Selonia farms [Latvia] | Nezāļu izplatība un augsnes potenciālā nezāļainība Sēlijas saimniecībās
2019
Jermuss, A., Latvia Univ. of Life Sciences and Technologies, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agronomy | Lapins, D., Latvia Univ. of Life Sciences and Technologies, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agronomy | Svarta, A., Latvia Univ. of Life Sciences and Technologies, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agronomy | Jermusa, G., Latvia University of Life Sciences and Technologies, Skriveri, Skriveri Municipality (Latvia). Inst. of Agronomy | Sanzarevska, R., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture
The aim of the study was to analyse and explain the changes in the occurrence of weed species and the weed seed bank in agrocenosis depending on the choice of precrops and agrotechnique in the farm. In order to perform weed monitoring from 2013 to 2017, farms of three different sizes were randomly selected in Selonia, Zemgale region. The number of weeds was measured according to the occurrence method in six specific fields of each farm once in growing season. The weed seed bank was identified in 2018 in two different soil tillage farms with traditional ploughing and minimal soil tillage, as well as in various sloping areas of the terrain un Selonia: the top of the hills and parts of the south-eastern slope. The average soil sample was analysed in 25 places at a depth of 0−0.05 m of the field. In Selonia region such weeds as field pansy (Viola arvensis M.), fat-hen (Chenopodium album L.), purple deadnettle (Lamium purpureum L.), black-bindweed or wild buckwheat (Fallopia convolvulus (L) A.Loeve) and common fumitory (Fumaria officinalis L.) were most frequently determined. The botanical composition of the weed seed bank differed from the monitored weeds in previous years. Annual and hardy-annual weed seeds in soil samples were determined. In the regular ploughing field only four different weed species were represented. Eight weed species in soil samples taken at the top of the hills and nine weed species in soil samples from the southeastern slopes occurred. The weed seed bank in the field under regular soil ploughing was three times lower than under gentle soil tillage. As a result of minimal soil tillage, the weed seed bank increased due to the concentration of weed seeds in the upper soil horizon, while the ploughing resulted in the weed seeds spreading in the deeper layers of the soil reducing the potential soil weediness. Seeds of weeds with shorter lifespan are destroyed by ploughing the soil, as seed germination conditions are limited over time.
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