What type of herbicide is applied prior to crop planting?

The correct choice is the type of herbicide that is applied before crops are planted, which is known as a preplant or burndown herbicide. This type of herbicide is specifically formulated to control existing weed populations and prepare the land for planting. It works by targeting weeds before the crop emerges, ensuring that the field is free of competition for nutrients, water, and sunlight, which is critical for the healthy establishment of the crop.

Preplant or burndown herbicides are commonly used to manage perennial weeds and can often be applied shortly before planting to maximize efficacy while minimizing potential phytotoxicity to the upcoming crop. This proactive approach to weed management is essential for increasing crop yields and ensuring optimal growing conditions.

In contrast, post-emergence herbicides are applied after the crop has emerged and is established, making them unsuitable for addressing weed issues prior to planting. Pre-emergence herbicides are applied after the crop has been sown but before it germinates, targeting weeds that may emerge alongside the crop. Residual herbicides refer to those that continue to work over time after application, but they are not specifically defined by when they are applied in relation to planting.