Seedling Emergence Patterns and Cohort Dynamics of Stellaria media in Relation to Tillage System and Sowing Date

Abstract

Seedling emergence patterns and cohort dynamics of Stellaria media were investigated in relation to tillage system and sowing date to understand its recruitment behavior in arable agroecosystems. Field experiments were conducted under contrasting soil disturbance regimes and multiple crop sowing schedules, and emergence was monitored at regular intervals throughout the growing season. Results indicated that emergence of S. media occurred in distinct cohorts, strongly influenced by soil disturbance intensity and timing of sowing. Conventional tillage promoted a more synchronized early-season flush of emergence due to enhanced soil–seed contact and exposure to favorable germination conditions, whereas reduced or zero tillage systems resulted in prolonged, staggered emergence patterns driven by surface seed persistence. Earlier sowing dates were associated with higher cumulative emergence, reflecting better alignment with optimal temperature and moisture conditions for germination. In contrast, delayed sowing reduced emergence intensity but extended the emergence window across the season. Cohort analysis revealed that seedling recruitment was highly responsive to microenvironmental variability, particularly soil moisture fluctuations and light availability at the soil surface. The persistence of viable seeds in the upper soil layer contributed to continuous recruitment, reinforcing the weed’s adaptability under diverse management systems. These findings highlight the role of agronomic practices in shaping weed population dynamics and underscore the importance of integrated weed management strategies that combine tillage modification and optimized sowing schedules to suppress S. media establishment in cropping systems.