1964

Drip Irrigation

Simcha Blass (1897–1982)

Farmers have been irrigating fields for centuries. They can let water flow into fields through irrigation channels or set up overhead sprinkler systems. But if farmers use these techniques in an arid climate, they do not work very well. There probably is not enough water available for flood irrigation, and too much water evaporates into the air with a traditional sprinkler system. Center-pivot irrigation would not work here.

Thus it makes sense that in Israel a new irrigation system would appear. Engineer Simcha Blass, with his son Yeshayashu and in conjunction with Kibbutz Hatzerim, patented the first surface drip irrigation emitter functional for practical use. Israel is extremely arid and fresh water is a scarce resource. The drip irrigation approach, patented in 1964, became a new standard for water-saving irrigation.

The basic idea is simple. Water drips onto the roots of each plant individually. Plastic pipes carry the water around the field, and special emitters that are immune to clogging control the rate of water delivery.

There are several important advantages embodied in this engineering approach. The main one is that it drastically reduces evaporation. The water drips directly onto the soil where it is absorbed immediately. There is no time where it is flying through hot, dry air and evaporating.

The second advantage is that the water concentrates where it is needed: in the root zone. The ground between plants, which contains many fewer roots, never receives moisture. This reduces surface evaporation and also cuts down on weeds.

Another advantage is that drip irrigation helps turn gray water and wastewater into irrigation water. If water has not been treated, it is not advisable to aerosolize it by spraying it in the air. Drip irrigation applies the water directly to the soil, or directly into the soil with subsurface emitters, so the wastewater becomes completely safe.

Drip irrigation is another great example of an engineering reconceptualization that yields multiple benefits from a different way of thinking. It has opened up far more land for farming. For example, all of the cotton grown in Israel (more than 100,000 tons per year) is drip irrigated. It would be nearly impossible to grow it otherwise.

SEE ALSO Center-Pivot Irrigation (1952), Desalination (1959), Green Revolution (1961).

Drip irrigation is a water-saving innovation that many of us use in our home gardens today.