Weed control：練習題

A farmer uses a hoe to remove weeds from between rows of maize. Which category of weed control does this represent?

A farmer observes that a specific weed species spreads rapidly through the field using underground stems. Which mode of spread and harmful effect best describes this situation?

When using systemic herbicides, why is it often necessary to wait several days before observing the full effect on the weeds?

Which of the following is considered a cultural method of weed control?

How does mulching help in weed control?

What type of chemical herbicide is designed to kill specific weeds without harming the main crop?

Explain why the timely removal of weeds during the early stages of crop growth is critical for achieving a high crop yield.

Explain why weeds that reproduce and spread via underground rhizomes present a greater challenge for mechanical control than those that reproduce solely by seeds.

(a) Identify one named local weed species that affects a specific crop and state one method by which it is spread.
(b) Describe two harmful effects this weed species has on the growth and yield of the crop.
(c) Why is it important for farmers to control weeds before they reach the flowering stage?

Weed management involves various strategies to reduce competition with crops.
(a) Distinguish between mechanical and cultural methods of weed control.
(b) Provide one specific example for a mechanical control method and one for a cultural control method.
(c) Explain how the use of a mulch can help in controlling weed growth in a vegetable garden.