Cover crops (CCs) are recognised as valuable for weed management, while fallow soil between cash crop seasons likely increases weed presence. Weeds may offer similar ecosystem services as CCs, although they pose a risk of seedbank buildup. This study evaluated the impact of two winter CC systems (3-year triticale cultivation, TRIT; and a 3-year succession of rye, clover, and mustard, RCM) compared to weedy fallow (WF) on weed seedbank size and composition in a 3-year ‘maize ( L.)–maize–soybean ( (L.) Merr)’ crop succession. After 3 years, seed density of spring/summer weeds reduced in all treatments, potentially stemming from herbicide use during cash crop seasons and tillage operations. Triticale had the lowest seedbank density (9,487 seeds m²) and higher diversity (Shannon Index 6.9) compared to WF (28,543 seeds m² and 4.1, respectively). Furthermore, stochastic analysis revealed a lower risk of enlarging weed seedbanks in TRIT compared to WF (for seed densities above 900 seeds m). Moreover, management practices (CCs, cash crop sowing, termination/harvest) synchronised with weed seed production and germination likely contributed to the decreasing seed density of species including and , which were reduced by 90 and 80 %, respectively, by the study’s end. Over three years, autumn/winter and indifferent weed seed densities increased 4.2 times more in WF and RCM (22,638 seeds m²) than in TRIT. This may be due to the varying growth rates among CC species in RCM, whereas TRIT consistently established rapidly, potentially outcompeting weeds until termination. Fallow periods between cash crops may increase weed species linked to that season and future crop–weed interference in varied crop rotations. Introducing CCs can mitigate this effect, although the choice of CC species may influence the extent of the impact.

中文翻译：

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揭示冬季覆盖作物和杂草休耕对土壤种子库的影响


覆盖作物（CC）被认为对杂草管理有价值，而经济作物季节之间的休耕土壤可能会增加杂草的存在。杂草可能会提供与 CC 类似的生态系统服务，尽管它们会带来种子库积累的风险。本研究评估了两种冬季 CC 系统（三年小黑麦种植，TRIT；以及三年连续种植黑麦、三叶草和芥菜，RCM）与杂草休耕 (WF) 相比对杂草种子库大小和组成的影响。 3 年“玉米 (L.)–玉米–大豆 ((L.) Merr)”作物演替。 3年后，所有处理中春/夏季杂草的种子密度均降低，这可能是由于经济作物季节和耕作操作期间使用除草剂所致。与 WF（分别为 28,543 粒种子平方米和 4.1）相比，小黑麦的种子库密度最低（9,487 粒种子平方米），多样性较高（香农指数 6.9）。此外，随机分析显示，与 WF 相比（种子密度超过 900 粒米），TRIT 中扩大杂草种子库的风险较低。此外，与杂草种子生产和发芽同步的管理实践（CC、经济作物播种、终止/收获）可能导致包括 和 在内的物种种子密度下降，到研究结束时，种子密度分别减少了 90% 和 80%。三年多来，WF 和 RCM 中的秋冬和中性杂草种子密度（22,638 粒种子平方米）比 TRIT 中增加了 4.2 倍。这可能是由于 RCM 中 CC 物种的生长速度不同，而 TRIT 始终快速生长，有可能在竞争中胜过杂草直至终止。经济作物之间的休耕期可能会增加与该季节相关的杂草种类以及未来不同作物轮作中的作物-杂草干扰。 引入 CC 可以减轻这种影响，尽管 CC 物种的选择可能会影响影响的程度。