(1964) Hoffman-Kąkolowa, I.; Wyższa Szkoła Rolnicza w Szczecinie. Katedra Ogólnej Uprawy Roli i Roślin
During a period of 3 years, observations in flora tables conducted before and after planting registered 59 weed varieties. The number of specimens per 1 m² varied from 1700 to only a few, with the predominance of yearly spring and winter varieties. The spread of weeds was due to after-cultivations and an enormous number of seeds in the soil. In the soil samples taken for testing, seeds of 51 weed varieties were found, and in 1 m² of arable soil, there were 99,500 to 267,000 seeds.