AP®︎ Environmental Science: Topic 5.5 Flashcards

Artificially applying water to agricultural land to support crops; agriculture accounts for about 70% of human freshwater consumption globally

The proportion of applied irrigation water that remains available to crops rather than being lost through evaporation or runoff

Water flows by gravity through trenches between crop rows; it is inexpensive but loses about one-third of its water to evaporation and runoff

A field is temporarily covered with water; it is simple and inexpensive but loses about 20% to evaporation and runoff and can cause waterlogging

Groundwater is pumped through spray nozzles across a field; 25% or less is lost to evaporation and runoff, but the system is more expensive than flood or furrow irrigation and requires energy

A form of spray irrigation in which a long sprinkler arm rotates around a central pumping point, producing circular irrigated fields

Perforated hoses release small amounts of water directly near plant roots; it loses only about 5% but is expensive to install

Excess irrigation water saturates soil and raises the water table into the root zone, depriving roots of oxygen

The buildup of salts left in soil when irrigation water evaporates, eventually reducing plant water uptake and becoming toxic to crops

Groundwater is withdrawn faster than recharge replaces it, lowering the water table and reducing future water availability

An aquifer beneath the central United States that has been heavily pumped for irrigation, with withdrawals exceeding recharge and substantially lowering groundwater levels