Assessment of Low-head Drip Irrigation Systems Uniformity of Application

Abstract

Water application uniformity (EU) is an important performance criterion that must be considered in the design, operation and management of irrigation systems for increasing agricultural productivity. This research study was as a result of the previous studies done by [5,6,7], which reported about poor/non-uniformity of water application by low-head drip irrigation systems. The study identified systems widely adopted by the smallholder farmers alongside low-cost green housing technology, categorized them based on layout configuration, height of water tank, lateral length, type, size and number of emitters and assessed their water application uniformities as recommended by the American Society of Agricultural Engineers (ASAE) Standards of 2003 using ASAE standards 1996(a) performance rating. This was done in order to compare their performances and diagnose constraints to enhance agricultural productivity.

This research was done in Trans Nzoia West Sub-County, Kenya. Four replications of each category in operation were selected by simple random sampling and water discharges filling a 10 ml cup (medicine dispenser) were timed from each of the thirty sampled emitters of each system. The data collected was processed and statistically analyzed to determine the sample mean, the confidence interval for the single mean and tested for significance difference between the sample mean of EU for the categorized systems. The result obtained together with the information gathered through semi-structured interviews was used in the conclusions of the report.

The result from this study showed that uniformity of water application performance rating for common low-head drip irrigation systems are marginally fair (71%) on average except for the two categories with double emitters whose performances are not acceptable (< 60%). Choice of designs having fair or good water application uniformity coupled with proper installation and management is needed for the enhancement of agricultural productivity. The categories whose performance ratings are not acceptable should not be promoted by extension providers and are recommended for further hydraulic uniformity test.