Question
Explain various effects of weeds on crop plants.

Answer

Effect of weeds on crop plants:
  1. The growth of weeds in the crop fields is harmful because they compete with the crops for nutrients, water, space and light.
  2. The weeds spread crop pests and diseases by acting as alternate host to insects and microorganisms.
  3. Some weeds may produce toxic substances which may interfere with the growth of crop plants.
  4. During harvesting weeds get mixed with crop's produce to downgrade its quality.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Why lead compounds are added to petrol? How is it harmful?

Show diagramatically the electron distributions in a sodium atom and a sodium ion and also give their atomic number.

Write the formula to calculate the speed of a body moving along a circular path. Give the meaning of each symbol which occurs in it.

If the relative density of a substance is 7.1, what will be its density in SI units?

The scientists now say that there are actually five states of matter A, B, C, D and E. The state A has a fixed volume but no fixed shape. The state B can be compressed very easily by applying pressure and state C has a fixed shape as well as a fixed volume. The state D is mixture of free electrons and ions whereas state E is named after an Indian scientist and a famous physicist.
  1. Name the physical states (i) A (ii) B (iii) C (iv) D, and (v) E.
  2. Name one substance belonging to state C which can directly change into vapours on heating. What is this process known as?
  3. Name one substance which normally belongs to state B but whose solid form changes directly into gaseous state.
  4. Name the most common substance belonging to state A.
  5. Which state of matter makes the sum and other stars to glow.
What is the value of acceleration in the following graph:

Describe structure and functions of Golgi apparatus.

Explain why, ice at 0°C is more effective in cooling than water at the same temperature.
Why burns caused by the steam are much more severe than boiling water?
A ball thrown up vertically returns to the thrower after 6s. Find its position after 4s.