Answer:

1. Weeds are plants that grow in cultivated fields along with the crop and compete with crop for nutrients, light, and space thereby causing great harm to the crops. The harmful effects of weeds are: It reduces the productivity of crop plant as the plant gets lesser nutrient, light and space.

2. Solar radiation is essential for plant growth. ... In theory, as the amount of captured radiation energy increases, crop production will also increase. When plant leaves absorb the energy of the sun for photosynthesis, the temperature of the leaf surface increases

3. If the agricultural field has too much water, the roots can rot, and the crops won't get enough oxygen from the soil. If there is scarcity of water, the vital nutrients it needs cannot travel through the plant.