Creating deep channels (gullies) is not a measure to reduce soil erosion.

Explanation:

Soil erosion is the process by which soil is moved from one location to another, usually by wind, water, or human activities. It is a significant environmental problem that leads to the loss of fertile topsoil, nutrient depletion, and water pollution. Implementing effective measures to reduce soil erosion is crucial for sustainable agriculture and environmental conservation.

a) Creating deep channels (gullies):
- This measure involves digging deep channels or gullies in the land to divert excess water and prevent it from causing erosion. However, this method is not effective in reducing soil erosion because it only redirects the water flow, which can still lead to erosion in other areas. Moreover, creating deep channels can disrupt the natural drainage patterns and cause further soil disturbance.

b) Contour ploughing:
- Contour ploughing is a technique where furrows are ploughed along the contour lines of the slope. This helps to slow down the water flow and prevent it from carrying away the topsoil. The furrows act as barriers, reducing the erosive force of the water and allowing it to infiltrate the soil.

c) Strip cropping:
- Strip cropping involves planting different crops in alternating strips or bands across the slope. This method helps to break up the flow of water, trap sediment, and reduce erosion. The strips of crops act as buffers, absorbing the energy of the moving water and preventing it from carrying away soil particles.

d) Planting of shelterbelts:
- Shelterbelts are rows of trees or shrubs planted along the edges of fields or slopes. They act as windbreaks, reducing wind speed and protecting the soil from erosion. The trees also help to stabilize the soil with their roots and provide shade, which reduces evaporation and moisture loss.

In summary, creating deep channels (gullies) is not an effective measure to reduce soil erosion. Instead, techniques like contour ploughing, strip cropping, and planting of shelterbelts are more suitable and sustainable methods to mitigate soil erosion and protect the environment.