Monitoring & Evaluation
Statistically significant data indicates micro-irrigation technology increases incomes and water efficiency.
iDE’s monitoring and evaluation team conducted a rigorous quasi-experimental evaluation of crop production and income changes in Vietnam in February/March of 2016. The study found that the differences between treatment and control groups were statistically significant for all crop production indicators: seed costs, crop revenue, input costs, and crop profit. These results also demonstrated that micro-irrigation technology (MIT) users earned, on average, more than double per square meter of cultivated land than control households.
Specifically, treatment households earned $17 PPP (Purchasing Power Parity) of crop profit per square meter of land in comparison to control households who earned $8 PPP profit per square meter of land. Statistically significant results of this magnitude, particularly given the small sample size for the study, demonstrate the effectiveness of MIT.
Included in the same survey instrument was a module that collected self-reported farm-level water use across three distinct crop stages (seedling, growth, and fruiting). Measurements were taken on-site to calculate flow rates for irrigation systems, accounting for both micro-sprinkler and flood furrow or hosepipe methods. We found that treatment households use significantly less water for seeding and fruiting stages of the crop cycle, as well as in total summation, in comparison to control households per square meter of cultivation. In total, treatment households used 32 percent less water than control households.
In short, statistical results indicate that with micro-irrigation technology, farmers can double their income while using 30 percent less water than traditional flood and furrow irrigation.
Similar to Nicaragua, the study indicated that farmers implementing MIT shifted to higher value crops (which benefit from direct water application) as opposed to staple crops (watered by traditional methods). This could be attributed to the installation and coverage differences between the two methods. Staple crops (e.g., wheat, rice) have multiple plants with little separation between plants, making flood irrigation worthwhile. High-value crops (e.g., tomatoes, cucumbers, fruit trees) tend to be single stalk plants spaced some distance apart from each other, favoring the direct placement of drip irrigation lines and emitters that bring water directly to the stalk.
One of the consistent findings for MIT is the need to correctly install and maintain the system for it to be successful. Unlike some technologies that are simple replacements boosting production or capability (i.e., replacing a manually-powered pump with a diesel-powered one, enabling water lift at lower depths), MIT needs to be implemented holistically. A successful solution considers the environment (i.e., field undulation, water access, and location), crop choice, plot scale, and labor availability, among other issues.