A comparison between low-cost drip irrigation, conventional drip irrigation, and hand watering in Nepal

Access to irrigation water is a critical element in meeting the food demands of a rapidly increasing population in the Middle Mountains of Nepal. The recent introduction of low-cost drip irrigation (LCDI) to Nepal represents an affordable means of expanding irrigation into rainfed areas, thereby increasing land productivity. This study presents a comparison of the effects on soil volumetric water content and cauliflower yield of three irrigation methods (LCDI, conventional drip irrigation (CDI), and hand watering) operated under three different irrigation regimes in the Jhikhu Khola Watershed, Nepal. Irrigation regime R1 supplied only half of the estimated crop water requirement, characterized by small volumes applied on alternate days. The other two irrigation regimes (regimes R2 and R3), supplied the full estimated crop water requirement, however differed in application timing. Small volumes were applied frequently (daily) under regime R2, whereas in regime R3, greater water volumes were applied less frequently (alternate days for the majority of experiment). Although differences in the soil volumetric water content (SVWC) were present between the irrigation methods, differences were not consistent between the three irrigation regimes. Regardless of irrigation regime, cumulative cauliflower yields were lowest under conventional drip irrigation. In contrast, there were significant differences in cauliflower yield between LCDI and hand watering between irrigation regimes. Irrigation regime R1 resulted in lower SVWC and lower cumulative yields than regimes R2 and R3, however, water-use efficiency was greater under regime R1 than under regimes R2 and R3. These results suggest that LCDI and hand watering are both viable options to increase food production in water scarce, small-scale farming in Nepal, however, long-term economic and labour benefits are greater under LCDI.