Changes in weed seed bank and flora as affected by soil tillage systems

Abstract

Tillage not only changes soil properties but also serves as a weed control means. Different soil tillage systems were investigated in a long-term field experiment conducted during 2003-2012 at Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry. The experiment was carried out in a cereal-based crop rotation. The experimental design included the following tillage treatments: 1) conventional tillage (CT): mouldboard ploughing at 22-24 cm depth; 2) minimum tillage (MT): stubble cultivation at 10-12 cm depth, non-selective herbicide (glyphosate) spray applied after harvesting; 3) no tillage (NT): direct drilling, non-selective herbicide spray applied after harvesting. This paper presents the data from the 2007-2012 experimental period. To determine weed seed bank, soil samples were taken in 2007 after spring barley harvesting and in 2012 after winter oilseed rape harvesting. Samples of weeds for the determination of fresh and dry mass were collected in 2011 and 2012 in winter wheat and winter oilseed rape crops during the growing period. The weed seed bank in the soil significantly decreased over the five-year period. However, significantly the highest number of seeds in the soil was found in the no tillage plots. Significant differences in the weed species composition between the different tillage systems were recorded: no tillage system promoted infestation of some broadleaf weeds, particularly Capsella bursa-pastoris. The lowest weed mass was determined for the conventional tillage plots, compared to minimum tillage, and especially no tillage plots.

Changes in weed flora under the influence of long term application of liming and reduced soil tillage

“…The lowest (16.7-19.3%) seed number was found at a soil depth of 20-30 cm. Soil contamination with weed seeds depended on crop condition as well as application of agromeasures and corresponds to consistent patterns indicated in literature (Woźniak, Soroka, 2015;Auškalnienė et al, 2018;Skuodienė et al, 2018). The seed bank is an indicator of past and present weed populations.…”

“…In high productivity Cambisol with pH 6.9-7.0, significant differences in the weed species composition between the different tillage systems were recorded: no tillage system promoted infestation of some broadleaf weeds, particularly shepherd's purse (Capsella bursapastoris (L.) Med.). The lowest weed mass was determined for the conventional tillage plots compared to minimum tillage, and especially for no tillage plots (Auškalnienė et al, 2018). In low productivity Retisol with pH 5.1-5.3, primary soil tillage method had significant impact on the weediness of crop rotation in all experimental years.…”

Integrated weed management in long-term maize cultivation

“…From a longterm experiment, one year overview showed that soil tillage and level of fertilizer application influenced weed fresh biomass and, because of high propagation level of perennial species, weed fresh biomass was the highest under no-tillage (149.6 g m -2 ) even without fertilizers application ( Fig.). Results of regression analysis pointed out that weed fresh biomass decreased when intensity of soil tillage increased from no-tillage to conventional tillage (Auškalnienė et al, 2018). On the other hand, weed fresh biomass was negatively correlated (R = −0.66) with maize yield in unfavourable and dry years (Simić, Dolijanović, 2016).…”

Development of herbicides resistance in Apera spica-venti in Lithuania

“…The interest in reduced (non-inversion) soil tillage in Lithuania has emerged over the last decades as well. It was established that shallow ploughing and rototilling did not exert any negative effect on soil agrochemical and physical properties (Feiza et al, 2011), and shallow tillage can give similar yields to mouldboard ploughing (Arvidsson et al, 2014), nonetheless the amount of seeds in the soil, as well as weed mass was significantly higher in less disturbed systems particularly in reduced-tillage system (Auškalnienė et al, 2018;Kadziene et al, 2020).…”