Furrow irrigation


 Furrow irrigation is a type of surface irrigation in which trenches or “furrows” are dug between crop rows in a field. Farmers flow water down the furrows (often using only gravity) and it seeps vertically and horizontally to refill the soil reservoir. Flow to each furrow is individually controlled. Furrow irrigation works well for row crops, tree crops and, because water does not directly contact the plants, crops that would be damaged by direct inundation by water such as tomatoes, vegetables, potatoes and beans. One of the oldest methods of irrigation, furrow irrigation is cheap and low-tech making it particularly attractive in the developing world or places where mechanized spray irrigation is unavailable or impractical.

 

One of the difficulties of furrow irrigation is ensuring uniform dispersion of water over a given field. In order to address this problem, some farmers engage in field leveling to remove any small hills that would have been bypassed by the gravity flow of the water. Additionally, some farmers employ a type of furrow irrigation known as “surge irrigation” in which water is pulsed on and off at given intervals. This wetting and drying of the soil can help “seal” the soil and encourage better water flow across the entire field instead of losing significant amounts of water to the areas of the field where the water is first pumped. Another difficulty with furrow irrigation is the increased potential for water loss due to runoff (although water loss to evaporation is less relative to mechanized spray irrigation). Building retention ponds along the edges of fields can help capture this runoff, allowing it to be pumped back to the upslope side of the field for use in further irrigation cycles.

 

Resources:

“Irrigation Water Use: Surface Irrigation.” Water Science for Schools. 2011. USGS. 19 Oct. 2011. http://ga.water.usgs.gov/edu/irfurrow.html

“Guidelines for Designing and Evaluating Surface Water Systems.” FAO Corporate Document Repository. Food and Agriculture Association of the United Nations. 19 Oct. 2011. http://www.fao.org/docrep/T0231E/t0231e04.htm#2.2.3%20furrow%20irrigation

 

Entry: BW

Checked: jh