Germination Response and Seedbank Characteristics of Geranium dissectum in Winter Grain Legume Cropping Systems

Abstract

Seed germination behavior and soil seedbank dynamics of Geranium dissectum were investigated in winter grain legume cropping systems to understand its ecological adaptability and persistence under temperate agroecosystems. Laboratory germination experiments were conducted under varying temperature regimes and moisture conditions to assess germination response, while field studies and soil sampling were performed to evaluate seedbank density, vertical distribution, and seasonal emergence patterns. Results indicated that germination of G. dissectum was strongly influenced by temperature fluctuations, with higher germination rates observed under cool to moderate temperature conditions typical of winter cropping periods. Moisture availability significantly enhanced germination, whereas drought stress conditions reduced both germination percentage and seedling vigor. Seedbank analysis revealed substantial persistence of viable seeds in the upper soil layers, particularly in fields subjected to reduced tillage practices. Seasonal emergence patterns were closely associated with rainfall events and soil temperature, with peak emergence occurring during early winter and early spring periods. Continuous cultivation of winter grain legumes influenced seedbank composition, favoring the persistence of adaptable broadleaf weed species such as G. dissectum. Emerged seedlings exhibited strong early growth potential, enabling competitive advantage in resource-limited environments. However, emergence declined in fields with higher crop canopy density and effective ground cover, indicating partial suppression by competitive crop stands. The species demonstrated a persistent seedbank strategy, contributing to long-term survival and recurrent infestations in winter cropping systems. The findings highlight the importance of understanding germination ecology and seedbank dynamics for effective management of G. dissectum in grain legume-based rotations. Integrated weed management strategies incorporating crop rotation, timely tillage, and optimized crop density may significantly reduce seedbank replenishment and emergence pressure.