Comparing efficiencies of flood and drip irrigation methods in onion production under farmer's production conditions in Omusati region, Namibia
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Date
2018
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Publisher
University of Namibia
Abstract
The study was conducted in 2015 at Ogongo Campus of the University of Namibia (UNAM) to compare efficiencies of flood and drip irrigation methods, normally used by small scale farmers in the Omusati Region of Namibia, at three different irrigation levels of 100, 80, and 60% Crop evapotranspiration (ETo). Irrigating at lower levels than full irrigation is also referred to as deficit irrigation. Furthermore, the study compared gross margins and assessed yield and growth indicators under the two irrigation systems using onion as the crop. A split-plot in a randomized complete block design (RCBD) experiment was carried out on a 43 m*34 m plot with soil physical and chemical characteristics analyzed before cultivation. The results indicated that 60% of ETo had a higher water use efficiency (WUE) of 4.6 kg m-3 in drip irrigation than 2.8 kg m-3 for the flood. At 80% level, water use efficiency of drip was 3.6 kg m-3 compared to 2.1 kg m-3 for the flood. At 100% levels, the water use efficiency was 2.9 kg m-3 for drip compared to 1.8 kg m-3 for the flood irrigation method. WUE is significantly different at all three levels of irrigation (p =0.008) and also significantly different for the irrigation type (p = <.001).The total volume of water used under the drip irrigation system was less compared to flood irrigation system by 32.3%. Results also show that there was a saving of water in drip irrigation by a margin of 30.7% for the 100% levels, by 33.3% each for the 80 % and 60% levels. As for moisture content, drip irrigation at 100% was better than flood at 100% by 0.74% whist at 80% drip was better than flood by 1.14%, and at 60% drip was better than flood by 0.03%. The yield productions of all treatments were highly significant at 0.4, 0.29 and 0.19 eta squared. The irrigation type was highly significant (p< 0.001). Irrigation level at 20wt is (p=0.008), irrigation level at 10 wt. is significantly different at (p <0.001) and at 5wt, it is also highly significantly different at (p<0.001). However, the interaction between level of irrigation and irrigation type are not significantly different at 20wt (p=0.415) and 10wt (p=0.224). Results show that more yields were obtained in drip irrigation by a margin of 5% for the 100% levels, by 9.4% for the 80 % levels and 9.5 % for the 60% levels. However, plant height/growth rate was not significantly different at all the three levels (p =0.397) of irrigation. A higher growth rate was obtained in drip irrigation treatment by a margin of 28.36% for the 100% levels, by 3.65% for the 80 % levels and 22.38 % for the 60% levels. In addition, the results showed that the gross margin for drip at 60 ETo was higher than for flood by 44.7%, while at 80 of ETo, the gross margin for drip was more than for flood by 64.6%. The gross margin is highly significantly different at all three levels of irrigation (p =0.001) and also significantly different for the irrigation type (p = <.001). The present study suggests that the small scale Namibia farming community should adopt deficit drip irrigation method instead of the old traditional flooding methods.
Description
A research submitted in fulfillment of the requirements for the Degree of Master of Science in Agriculture
Keywords
Drip and flood irrigations methods, Water use efficiency, Yield of onions