Which are examples of how farmers can prevent topsoil erosion?

There's multiple ways as to how the topsoil can be protected from erosion and some of the most productive and easiest are:

- plowing in cross cut manner in accordance to the fall of the soil;

In this way the soil will be flatter, thus the erosion will be minimized.

- planting trees or bush type plants that have deeper and wider roots;

The large roots systems will keep the soil tightly, thus preventing the erosion.

- using biomass as a fertilizer;

It will both create a nice fertile layer, and not be damaging for the soil.

- not using pesticides;

They ruin the compactness of the soil, thus making it looser, so it is better to be avoided.

- using sprinklers fro irrigation instead of irrigation ditches;

The sprinklers will perform irrigation in the manner of water falling from above, thus not moving the soil, unlike the irrigation with irrigation ditches where the upper layers are washed away by the water.