With more than 65% of agronomic crops under no-till in Pennsylvania, herbicides are relied on for weed management. To lessen the environmental impact and selection pressure for herbicide resistance, we conducted a 9-yr experiment to test herbicide reduction practices in a dairy crop rotation at Rock Springs, PA. The rotation included soybean [Glycine max (L.) Merr.]–corn (Zea mays L.)–3-yr alfalfa (Medicago sativa L.)–canola (Brassica napus L.). The following practices were used to reduce herbicide inputs: (a) banding residual herbicides over corn and soybean rows and using high-residue inter-row cultivation; (b) seeding a small grain companion crop with alfalfa; (c) plowing once in 6 yr to terminate the perennial forage. These practices were compared with standard herbicide-based weed management (SH) in continuous no-till. We hypothesized: (a) There would be more weed biomass in the reduced herbicide treatment (RH), (b) leading to more weeds in RH over time, but (c) the added weed pressure would not affect yield (d) or differences in net return. We sampled weed biomass in soybean, corn, and the first two forage years. In corn and soybean, weed biomass was often greater in RH than SH and increased over the years in the RH treatments. In the forage, weed biomass did not always differ between treatments. Yield and differences in net return were similar in most crops and years. Results suggest that weed management with reduced herbicide inputs supplemented with an integrated approach can be effective but may lead to more weeds over time.

中文翻译：

---

在免耕乳业轮换中减少除草剂的综合杂草管理

在宾夕法尼亚州，超过 65% 的农作作物都处于免耕状态，因此人们依赖除草剂来管理杂草。为了减轻除草剂抗性的环境影响和选择压力，我们进行了一项为期 9 年的实验，以测试宾夕法尼亚州罗克斯普林斯奶牛作物轮作中减少除草剂的做法。轮作包括大豆 [ Glycine max (L.) Merr.]-玉米 ( Zea mays L.)-3 年苜蓿 ( Medicago sativa L.)-油菜 ( Brassica napus)L.）。以下做法用于减少除草剂的投入： (a) 在玉米和大豆行上使用残留除草剂，并使用高残留行间种植；(b) 用苜蓿播种小粒伴生作物；(c) 每 6 年耕一次以终止多年生草料。将这些做法与连续免耕中基于除草剂的标准杂草管理 (SH) 进行了比较。我们假设：(a) 在减少的除草剂处理 (RH) 中会有更多的杂草生物量，(b) 随着时间的推移导致 RH 中的杂草更多，但是 (c) 增加的杂草压力不会影响产量 (d) 或差异在净回报中。我们对大豆、玉米和前两个牧草年的杂草生物量进行了采样。在玉米和大豆中，RH 中的杂草生物量通常大于 SH 中的杂草生物量，并且在 RH 处理中随着时间的推移而增加。在饲料中，处理之间的杂草生物量并不总是不同。大多数作物和年份的产量和净收益差异相似。结果表明，减少除草剂投入并辅以综合方法的杂草管理可能有效，但随着时间的推移可能会导致更多的杂草。