The effect of crop rotation on soil seed banks

Abstract

Crop rotation, soil cultivation and weed control measures are in direct correlation with the content of the weed seed bank in the soil. Knowing the weed seed bank and the dynamics of the weed emergence is the basis for planning and implementing the measures for effective weed control. The research was carried out on the plots of the long-term stationary experiment 'Plodoredi' of the Institute of Field and Vegetable Crops in Novi Sad. During August of 2014, following the soybean harvest, the soil from the plots under different cultivation systems was sampled: soybean monoculture and 3-field (soybean, wheat, corn). Two methodological procedures were used to evaluate the reserve of seeds in the plough layer and the under plough soil layer. The physical extraction of seeds has determined the total content of weed species in the seed bank, while seed germinarion was used to determine which of the observed species are capable of germinating in the following period. The method of physical extraction has determined that the highest number of seeds was present in the soil samples from the soybean monoculture, in the depth layer of 15-30 cm. The under plough soil layer was characterized by a lower number of seeds, in both variants. In the study of germination, which was conducted under controlled conditions 18 months after the sampling, the best seed germination was recorded for the seeds of Ambrosia artemisiifolia L., Chenopodium hybridum L. and Chenopodium album L.

Plodored, obrada zemljišta i nega useva koja uključuje mere suzbijanja korova su u direktnoj korelaciji sa sadržajem rezervi semena korovskih biljaka u zemljištu. Poznavanje rezervi semena i praćenje dinamike pojave korova je osnova u planiranju i sprovođenju mera za efikasno suzbijanje korova. Istraživanje je sprovedeno na višegodišnjem stacionarnom ogledu 'Plodoredi' Instituta za ratarstvo i povrtarstvo u Novom Sadu. Tokom meseca avgusta 2014. godine, nakon žetve soje uzorkovano je zemljište sa parcela pod različitim sistemom gajenja: monokultura soje i 3-polje (soja, pšenica, kukuruz). Za procenjivanje rezervi semena korovskih biljaka oraničnog i podoraničnog sloja korišćena su dva metodološka postupka. Fizičkom ekstrakcijom semena utvrđena je ukupna zastupljenost semena korovskih vrsta u rezervi semena, dok su naklijavanjem utvrđene vrste čija su semena sposobna da klijaju u narednom periodu. Metodom fizičke ekstrakcije utvrđeno je da je najveća brojnost semena bila u sistemu monokulture soje iz sloja zemljišta 15-30 cm. Podoranični sloj je generalno u obe varijante sadržao značajno manji broj semena. U ogledu za naklijavanje, koji je sproveden u kontrolisanim uslovima 18 meseci nakon uzorkovanja, najveću klijavost semena pokazale su vrste: Ambrosia artemisiifolia L, Chenopodium hybridum L., i Chenopodium album L.