Germination Ecology and Seedling Emergence of Galium tricornutum Under Variable Soil Temperature and Burial Depth

Abstract

Variations in soil temperature and seed burial depth strongly influence the germination dynamics and field establishment of Galium tricornutum, a problematic broadleaf weed in cereal-based production systems. Controlled laboratory and greenhouse experiments were conducted to evaluate the effects of alternating temperature regimes and burial depths on seed germination behavior and seedling emergence patterns of this species. Seeds were exposed to constant and fluctuating temperatures ranging from 5–35°C, while emergence studies were performed at burial depths of 0–12 cm in sandy loam soil. Germination response was significantly affected by temperature, with maximum germination recorded under alternating temperatures of 20/10°C and 25/15°C, indicating an ecological preference for moderate thermal conditions. Extremely low and high temperatures considerably reduced germination percentage and delayed germination rate. Seedling emergence was greatest when seeds remained on the soil surface or were buried at shallow depths of 1–2 cm. Progressive reduction in emergence was observed with increasing burial depth, and no emergence occurred beyond 10 cm depth due to limited seed energy reserves and impaired shoot elongation. The findings demonstrated that G. tricornutum possesses adaptive germination traits enabling establishment under a wide range of environmental conditions, particularly in conservation tillage systems where seeds remain near the soil surface. Burial of seeds through deep tillage could substantially suppress field emergence and reduce weed infestation. Understanding the ecological requirements governing germination and emergence of G. tricornutum provides valuable information for predicting population dynamics and developing integrated weed management strategies aimed at minimizing crop yield losses in temperate agroecosystems.