The influence of varying soil tillage on the number and verticaldistribution of weed seeds in soil of the rye (Secale cereale) monoculture

摘要

In 22-year continuous cropping experiment with winter rye, the effect of varying post-harvest and pre-sowing soil tillage on the number of weed seeds and their vertical distribution in soil was studied. Growing rye in crop rotation increased number of weed seeds in each layer of the soil. However. continuous cropping rye decreased weed seed numbers particularly in 1-10 cm and 10-20 cm layers of the soil. Seed densities of Chenopodium album, Echinochloa crus-galli and Polygonum convolvulus were similar in each of the three examined soil layers. Seeds of Amaranthus retroflexus, Viola arvensis, Geranium pusillum and other species were stored in the upper soil layer near the soil surface, and their number was reduced with soil depth. Seeds of Viola arvensis and Geranium pusillum were met most frequently in soil from continuous cropping rye. Most favourable tillage practice that limited accumulation of weed seeds in soil was conventional tillage, with shallow ploughing after harvesting of rye and medium ploughing in pre-sowing tillage. Other tillage methods did not influence significantly soil infestation with weed seeds.