Weed abundance and soil seedbank responses to tillage systems in continuous maize crops

ABSTRACT

Weed abundance in crops undergoes frequent changes, often due to changes in tillage practices. Annual species, with quick germination, a short vegetative stage, profuse seed production and long-lived seeds become problematic under zero-tillage systems. Portulaca oleracea L. and Amaranthus blitoides L. are widespread weeds in the Mediterranean area, prominent in irrigated crops. We studied the total weed abundance in the field, and specifically these two species (Portulaca oleracea and Amaranthus blitoides) with high frequency of occurrence in monoculture maize, from 2012 to 2014, in the field and soil seedbank. Results showed significant differences between zero-tillage (ZT) and conventional tillage (CT) systems on total weed abundance and relative abundance of Portulaca oleracea. Total weed abundance decreased in ZT plots (from 136 plants m⁻² to 25 and 46 plants m⁻², in 2013 and 2014 respectively). The same trend was observed in Portulaca oleracea recorded in ZT plots, but the abundance of Amaranthus blitoides did not vary in this system. Weed seedling germination and weed seed numbers both of total weed seedbank and Portulaca oleracea, were greater in ZT plots compared to CT, regarding Amaranthus blitoides seedling germination and seed count, the values did not increase with ZT, in continuous maize crops.

KEYWORDS:

• Germination method
• irrigated crops
• seed extraction method
• weed infestation
• zero-tillage

Acknowledgments

We are grateful to David San Martín and José Silveria for helping managing the experiment. We are grateful to Charlotte Harvey for English editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been funded by Projects AGRISOST II S2013-ABI-2717 (Comunidad de Madrid and ESIF) and RTA 2013-00009-C02-01 and RTA2017-00006-C03-01 (Spanish Ministry of Economy and Competitive).