Which of the following practices can lead to resistant weed populations when using no-till?

The choice that indicates a practice leading to resistant weed populations in a no-till system is the continuous use of herbicides without rotation. When herbicides are applied repeatedly without varying the mode of action, weed species that are susceptible are killed off, while those with resistance traits survive and reproduce. This selective pressure encourages the increase of resistant weed populations over time, as the resistant individuals thrive in an environment where their competitors are being eliminated.

In contrast, practices like increased tillage, utilizing cover crops, and practicing crop rotation can help manage weed populations effectively and reduce the risk of herbicide resistance. Increased tillage can disrupt weed seeds and seedlings, while cover crops can suppress weed growth and add diversity to the weed management strategy. Crop rotation introduces different crops and, ideally, different herbicides or management practices, which reduces the likelihood of selecting for resistant weed populations.

Overall, it’s essential to vary weed management strategies to maintain the effectiveness of herbicides and prevent the development of resistance, particularly in a no-till context where the reliance on herbicides may be greater.