Agricultural Irrigation in China: an adaptation paradox

North China faces a paradox in considering adaptation measures under changing climate conditions predicted by existing climate models. On one hand, farmers, experts, and policy-makers are scrambling to respond to increased evaporation (due to high temperatures) and reduced growing season precipitation by converting traditional rain-fed crops and plots to some form of stable, resilient irrigated system. On the other hand, widespread switching from rain-fed agriculture to most traditional irrigation techniques has the potential to greatly increase water demand in an already water-stressed region.

A World Bank Guidance entitled “Climate Change Adaptation in the Agricultural Sector: Challenges and Opportunities”notes that drip irrigation technologies, which have the potential to replace traditional ditch or flood irrigation, can improve access to and adoption of water conserving practices and help irrigated systems to cope with lower water supply. The report goes on to note that “water conserving technologies are an effective way to maintain cropping intensity, and can provide opportunities to diversify into high-value market crops.”

Drip irrigationDrip irrigation, also known as trickle irrigation or microirrigation, is an irrigation method which saves water by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of pipes, tubing, and emitters.

However, drip irrigation faces a major challenge in the Chinese context. Modern irrigation systems have largely failed to meet the need for inexpensive and efficient irrigation systems for small farmers. Drip irrigation is widely recognized as one of the most efficient methods of watering crops. However, since its acceptance in the mid-1970s, the hardware has evolved to fit large fields and minimize management and labor requirements. As a result, the standard drip systems now available are large, sophisticated, and expensive – not appropriate for a country where the average farm size hovers around .13 hectares nationally.

Further, the cost of traditional drip systems remain prohibitive for all but high-value crops – not commodities and staples that form the basis of agricultural production and food security.

One promising alternative, described by Lester Brown’s Earth Policy Institute here, is low-tech, gravity driven drip systems that are spreading across small-scale farms in India. These systems, which are made up of a simple bucket connected to a plastic hose to distribute water—have been developed to irrigate small vegetable gardens. Larger systems using elevated drums can efficiently bring water to a 125 square meter plot while avoiding waste and evaporation.

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