agricultural

Irrigated agricultural:
Irrigation is the provision of water to enable an area of land  to be cultivated. Irrigation is needed in areas where :
Precipitation is low eg Pakistan & Egypt.
Precipitation is seasonal eg California
Precipitation is unreliable
The crops eg rice have special requirements.
In developing countries traditional irrigation. System are slowly being replaced by major modern irrigation projects. Often much of the capital for these projects is provided by developed countries. These large projects are not without their environmental consequence. For example the damming of the Nile at the Aswan high dam has reduced the supply of silt to the Nile valley requiring fertilizer tone used on fields. In the Pakistan water logging and salinity are the major threat to cultivated land.