Modern agricultural engineering categorizes standard irrigation methodologies into seven primary systems: surface irrigation (gravity-fed flooding), drip or trickle irrigation (delivering water drop-by-drop directly to plant roots), sprinkler irrigation (overhead spraying mimicking natural rainfall), center pivot irrigation (automated mechanized rotating sprinkler towers), sub-surface irrigation (introducing moisture beneath the soil crust), manual irrigation (watering via cans or hoses), and terraced irrigation used extensively in sloped mountainous terrains.