Refer to the infographic below on the South African berg wind. Explain why berg winds are associated with lower agricultural productivity on farms.

Step 1: Define berg winds based on the provided text.
Berg winds are winds that occur when air from the central plateau flows down the escarpment to the coast. This air undergoes heating due to the adiabatic process, increasing in temperature by approximately $1^\circ \text{C}$ per 100 metres of descent.

Berg winds are warm, dry winds that blow from the interior plateau down the escarpment to the coast, heating up adiabatically as they descend.