Economic renovation of a hillside drip irrigation system using drip tape inlet pressure regulators under...

In hilly areas, significant elevation changes necessitate the use of expensive pressure compensating drip tape to ensure safety and irrigation uniformity, which is economically unfeasible for developing countries. This article proposes a more cost-effective alternative: the use of inexpensive nonpressure compensating drip tape with a pressure regulator (PRL) installed at the inlet. Based on this approach, a low-cost modification of a hilly drip irrigation system with a maximum height difference of 53 m was achieved. The main conclusions are as follows: (1) A mathematical model was developed to account for the combined effects on the PRL outlet pressure, leading to a simulation method for assessing the hydraulic performance of drip systems with PRLs; (2) While maintaining irrigation uniformity (CU) greater than 90%, the system's one-time and average annual investments were reduced by 48.0% and 35.3%, respectively; (3) Taking the drip irrigation system researched in the manuscript as an example, the unit price of pressure-compensating drip tape must be less than 1 CNY/m (approximately 0.14 USD/m) to remain competitive in annual investment compared with the solution of installing a PRL at the inlet of non-pressure compensating drip tape.