What are the common methods of irrigation?

Irrigation methods include: Surface irrigation - water flows over soil (flood, furrow, basin) - simplest but least efficient (40-60%). Sprinkler irrigation - water sprayed through nozzles simulating rain (60-75% efficiency). Drip/trickle irrigation - water delivered directly to plant roots through emitters (85-95% efficiency). Sub-surface irrigation - water applied below ground surface. Selection depends on crop type, water availability, topography, soil type, and economics.