Question

To prevent soil erosion, a farmer plants a hedge across a field. This method works because
(a)The hedge prevents soil from the direct impact of rainwater
(b)The roots of plants prevents the soil erosion
(c)The hedge absorbs minerals from the soil, which makes it most compact
(d)None of the above

Answer 1

Hint: Soil erosion is a common problem faced by farmers in their agricultural lands. Therefore, processes like making hedges of vetiver grasses whose roots can hold the soil are good ways to prevent it from collapsing.

Complete answer:
The hedge planted by the farmer is of vetiver grass which roots catch the eroded soil and helps to build up terraces that can stabilize the site. Therefore, the hedges across the field prevent soil erosion with the help of its roots.

Additional Information: Vetiver grass (Chrysopogon zizanioides) is a bunchgrass native to Tamil Nadu, which is commonly used to prevent soil erosion by making hedges of it. There are several aspects of these grasses that make them perfect for it. They grow almost exclusively downwards, deeper than some tree roots. It can go as deep as 7ft to 13ft. This property of these grasses makes their hedges the excellent stabilizer hedge for stream banks, terraces, and rice paddies. The roots of these grasses bind to the soil so that it can not dislodge. These grasses are also used to stabilize railway cuttings in unsuitable locations so that mudslides and rockfalls can't occur. They penetrate and loosen the soils which are compact.
Therefore, the correct answer is “The roots of plants prevent the soil erosion”.

Note: Apart from the use of vetiver, there are several ways to prevent soil erosion such as applying mulches, matting the soil, contour farming, and terraces, windbreakers, etc. Other plants like herbs, wildflowers, and small trees are also used to bind the soil just like vetiver grasses. Some excellent choice for this is creepers as they spread on the ground crawling around instead of going straight up.