Modern drip irrigation uses water-dispersing tapes, tubes and nozzles to deliver water drop by drop to the exact location of individual plants in the field. This modern approach depends entirely on the development of suitable plastics for the technology involved. Older approaches that were not so efficient did use similar ideas. The basic concept of releasing less water in the right place dates back thousands of years.
Centuries ago in the Middle East, farmers developed an efficient way of irrigating trees in desert soil with a minimum of water. If poured directly on the ground, much water flows away from the plant and seeps beyond the reach of the roots. To control the flow of water, farmers buried special unglazed pots near the trees and periodically filled them with water. The water seeped through the clay walls slowly, creating a pocket of wet soil around the tree. Trees grew as well with the pot method as in orchards watered by trench irrigation.
Predecessors of today's drip irrigation systems included experiments with unglazed clay pipe systems in Afghanistan in the late 1800s. Research conducted by E. B. House at Colorado State University in 1913 showed that slow irrigation could target the root zone of plants. In Germany during the 1920s, researchers devised controlled irrigation systems based on perforated pipe. None of these systems proved as efficient as modern drip irrigation technology.
In the 1950s, plastics molding techniques and cheap polyethelene tubing made micro-irrigation systems possible for the first time. Though researchers in both England and France experimented with controlled irrigation, the greatest advancements came from the work of a retired British Water Agency employee--Symcha Blass. In Israel, Blass found inspiration in a dripping faucet near a thriving tree and applied his knowledge of micro-tubing to an improved drip method. The Blass system overcame clogging of low volume water emitters by adding wider and longer passageways or labyrinths to the tubing. Patented in 1959 in partnership with Kibbutz Harzerim in Israel, the Blass emitter became the first efficient drip irrigation method.
By the late 1960s, many farmers in both North and South America as well as Australia shifted to the new drip irrigation technology. Typical water consumption decreased from 30 percent to 50 percent. In the 1980s, drip irrigation saw use in commercial landscaping applications. Because the drip irrigation emitter technology focused water below ground in the root zone, these systems saved labor costs by reducing weed growth. With drip systems yards and gardens flourished without sprinklers or manual watering.
One of drip irrigation's bigger success stories involves the sugar plantations of Hawaii. Sugar cane fields require irrigation for two years before harvesting, and in Hawaii, the hillside fields make ditch irrigation impractical. Producers abandoned sprinkler systems in favor of the low-flow drip irrigation methods--a conversion which took 16 years. In 1986, 11 sugar plantations in Hawaii had completely shifted to drip irrigation. One plantation spanned 37,000 acres of drip-irrigated sugar cane fields. The total cost of the conversion reached $30 million.