Water saving irrigation techniques

Irrigation by gravity (furrow or surface irrigation) is the main irrigation technique used in Tajikistan for annual crops. In order to avoid erosion the irrigation should be made by furrows which are following slightly inclined contour lines. The water influx should be slow, so as to increase water infiltration into the soil and reduce the risk of erosion along the irrigation furrow. Furthermore, measures should be implemented to make irrigation by gravity more effective, e.g. by lining irrigation channels with plastic foil for reducing water loss through infiltration or by distributing the water to the furrows by plastic pipes for achieving a homogeneous allocation.

Special attention should be paid to avoid too much watering; excessive water should be evacuated properly as it can cause soil erosion, the formation of gullies or attract pests.

In a gravity irrigation system, it is crucial to break the soil surface between the furrows in order to destroy capillaries and thus preserve humidity.

More sophisticated and efficient irrigation techniques as drip and sprinkler irrigation are economically not viable in most cases in annual irrigated crops.

Water is a scarce resource in Tajikistan and the situation is worsening with population growth and in the wake of climate change. Therefore, farmers are interested in implementing water saving irrigation techniques. The means of choice is improving irrigation by gravity as in most cases it is too expensive to install drip or sprinkler irrigation systems for annual crops.

Many farmers are irrigating annual crops by gravity, letting the water simply flow downhill and are not aware that such a procedure causes erosion. They should be trained on implementing furrow irrigation following contour lines.