Weed Seedbank Depletion and Emergence Dynamics in Minimum Tillage vs. Conventional Tillage Maize Fields

Abstract

Weed seedbank depletion and emergence dynamics were investigated in maize (Zea mays L.) fields managed under minimum tillage and conventional tillage systems to evaluate long-term impacts on weed population persistence and recruitment patterns. Soil samples collected from different depths were analyzed to estimate seedbank density, species composition, and vertical distribution, while field emergence was monitored across the cropping season under both tillage regimes. Results indicated higher total weed seedbank density in minimum tillage systems, with pronounced concentration of viable seeds in the upper soil layers due to reduced soil disturbance. Conventional tillage redistributed weed seeds across soil profiles, resulting in temporary seedbank dilution but enhanced germination through burial and exposure cycles. Emergence dynamics showed distinct flushes synchronized with irrigation and rainfall events, with earlier and more uniform emergence observed in minimum tillage plots. Species composition analysis revealed dominance of small-seeded annual weeds under both systems, although perennial species were more persistent in minimum tillage due to reduced mechanical disruption. Seedbank depletion rates were faster in conventional tillage systems as a result of increased seed burial, germination stimulation, and seed mortality through soil inversion. However, repeated disturbance also facilitated periodic reinfestation through recruitment from deeper soil layers. Competitive interactions between maize and weeds were more intense during early growth stages in minimum tillage systems due to higher surface seed concentration and rapid emergence. The study highlights the contrasting effects of tillage practices on weed seedbank dynamics and emphasizes the need for integrated weed management strategies combining cultural, mechanical, and chemical approaches. These findings provide insights into optimizing tillage systems for sustainable weed suppression and improved maize productivity.