Gibson David J, Young Bryan G, Owen Micheal D K, Gage Karla L, Matthews Joseph L, Jordan David L, Shaw David R, Weller Stephen C, Wilson Robert G
Southern Illinois University, Carbondale, IL, USA.
Purdue University, West LaFayette, IN, USA.
Pest Manag Sci. 2016 Apr;72(4):692-700. doi: 10.1002/ps.4039. Epub 2015 Jun 15.
Shifts in weed species composition and richness resulting from near-exclusive reliance on herbicides in glyphosate-resistant (GR) cropping systems has necessitated the implementation of alternative weed management tactics to reduce selection pressures of herbicides. We contrasted the response of the weed soil seedbank to effects of weed management strategy, comparing grower practices with academic recommendations for best management practices (BMPs) over 6 years and across five weed hardiness zones in the US Midwest at sites subject to GR cropping systems.
Total weed population density and species richness varied according to cropping system, location and prior year's crop, but less so to weed management strategy. The seedbank population density for 11 of the 14 most frequent weed species was affected by weed management strategy either alone or in an interaction with hardiness zone or year, or both. In only 29% of comparisons was weed population density lower following academic recommendations, and this depended upon prior crop and cropping system. The population density of high-risk weed species was reduced by academic recommendations, but only in two of six years and under continuous GR maize. Overall, the weed population density was decreasing in field halves subject to the BMPs in the academic recommendations relative to grower practices.
The soil seedbank is slow to respond to academic recommendations to mitigate glyphosate-resistant weeds, but represents a biological legacy that growers need to keep in mind even when management practices reduce emerged field weed population densities.
在抗草甘膦（GR）种植系统中，由于几乎完全依赖除草剂导致杂草物种组成和丰富度发生变化，因此有必要实施替代杂草管理策略，以降低除草剂的选择压力。我们对比了杂草土壤种子库对杂草管理策略效果的响应，在美国中西部五个杂草耐寒区、采用GR种植系统的地块上，对种植者的实际做法与最佳管理实践（BMPs）的学术建议进行了为期6年的比较。
杂草总种群密度和物种丰富度因种植系统、位置和前茬作物而异，但受杂草管理策略的影响较小。14种最常见杂草中的11种的种子库种群密度受到杂草管理策略的单独影响，或与耐寒区或年份的相互作用影响，或两者皆有。在仅29%的比较中，遵循学术建议后杂草种群密度较低，这取决于前茬作物和种植系统。学术建议降低了高风险杂草物种的种群密度，但仅在六年中的两年且在连续种植GR玉米的情况下。总体而言，相对于种植者的实际做法，在遵循学术建议中的BMPs的田块中，杂草种群密度正在下降。
土壤种子库对减轻抗草甘膦杂草的学术建议反应缓慢，但它代表了一种生物学遗留问题，即使管理措施降低了田间杂草的出苗种群密度，种植者也需要牢记这一点。
