ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 107, No. 1 (2020), p. 25–32
DOI 10.13080/z-a.2020.107.004

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



Many soil improvement practices are directly related to the reduction of weed infestation in crops. Sustainable use of the acid moraine loam Bathygleyic Distric Glossic Retisol prevailing in Western Lithuania is associated with the appropriate intensity of liming and tillage. Research was carried out at the Vėžaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry during the period 2015–2018 in two long-term field experiments: liming (established in 1949) and soil tillage methods (established in 2003). The aim of the study was to establish the trends in weed infestation variation in the crop rotation after a long-term application of agronomic practices of different intensity (soil tillage and liming). Treatments of the soil tillage were as follows: conventional ploughing, shallow ploughing and shallow ploughless tillage. Treatments of liming were as follows: unlimed (pHKCl 4.0–4.1) and limed (pHKCl 6.2–6.8). The following weed infestation indicators were investigated: weed number and mass, weed species number, weed seed bank in the soil depths of 0–10, 10–20 and 20–30 cm.

Findings of the study suggest that the long-term liming had an impact on the disappearance of dominating acidophilic weeds from crop communities. In a limed soil (pH 6.4–6.8), the total number of weeds was 4.1 times lower compared to that in a naturally acid soil (pH 4.0–4.1). The contamination with weed seeds was 14.2 times greater in the naturally acid soil; however, irrespective of the soil acidity (pH), vertical seed distribution was determined to be similar in different depths of the soil. The long-term conventional ploughing reduced crop weediness in the soil of low acidity (5.1–5.3). The total weed number and mass were 1.6 and 1.4 times greater in the treatment of reduced tillage soil. The effect of long-term regular soil tillage tended to cause changes to the depth of soil loosening, affecting vertical weed seed distribution. Under reduced tillage conditions, the soil depth of 0–10 cm was the most contaminated with weed seeds.

Key words: acid soil, liming, primary soil tillage, seed bank, weed number and dry biomass.

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