Drag line irrigation: Practical experiences with sugar cane

• Published in: Agricultural water management 1990, Vol.17 (1), p.25-35
• Main Author: Zadrazil, H.
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Biological and medical sciences; CANA DE AZUCAR; CANNE A SUCRE; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; IRRIGATION; Irrigation. Drainage; RIEGO; SUGAR CANE
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/0378-3774(90)90053-2

Drag line irrigation is defined as an overhead sprinkler system, where sprinklers are connected by means of portable hoses and permanent or semi-permanent pipes to a pressurized water supply. The system has been derived from the conventional sprinkler system of portable pipes in order to reduce labour requirement for its operation. This has been achieved with a modest increase of capital costs, well below the comparative costs of other kinds of more automatic irrigation systems. Particular reference is made to Swaziland, South Africa and Kwa-Zulu, where drag line irrigation for sugar cane has been in operation for many years. According to climatic conditions, application rates have been designed for values between 0.5 and 1.0 l/s/ha. Alternative lay-outs are described with varying lengths of hoses, for permanent PVC laterals or semi-permanent portable pipes and technical details are discussed. Drag line irrigation can be well adapted for the irrigation of large areas of big estates or for smallholder irrigation with plot sizes as small as 1 ha and less. It can be successfully integrated with a conservation contour lay-out as required in hilly areas for erosion control. Labour requirements for the operation, suitably expressed in m 3 irrigated per man-day are indicated and compared to labour requirements for some other irrigation systems. Details of a particularly practical design for the application of 60 mm irrigation with a sprinkler spacing of 18 × 18 m and 2 sprinkler moves in 24 hours are presented. Reference is made to power demand and advantages to be gained by sub-dividing the scheme in 2 or more pressure zones in hilly areas are pointed out.