Comparative Efficiency Evaluation of Different Clay Pots Versus Bucket Irrigation System Under Swiss Chard (Beta vulgaris subsp. cicla) Growers Condition in Northern Ethiopia

Abstract

Rain-fed agriculture shares the largest crop production system in Tigray region. However, due to erratic nature of rainfall, crop production is always at a risk. For this reason crop production in the arid and semi arid regions of northern Ethiopia usually requires supplemental irrigation. In an effort to assist agricultural production under smallholder farmers, the Regional Bureau of Agriculture and Natural Resources has been looking for efficient and less costly irrigation methods. Although drip irrigation technology has been well known for its higher efficiency, its adoption was too slow due to its high initial cost and inadequate technical knowhow.  At the moment, in some areas of Tigray farmers have started practicing locally made low cost clay pot irrigation technology. However, the water use efficiency and its economic viability under smallholder farmers were not adequately understood. The objectives of this study were thus to examine the economical viability and estimate the water use efficiency of clay pot irrigation technology and to evaluate the performance of different clay pot design for irrigating Swiss chard (the most common leafy vegetable crop in this region). In this research traditional pot maker was instructed to manufacture four different clay pot designs (imperforated bar type, imperforated round shape type, perforated bar type and perforated round types) which were used for assessing performance of clay pot for irrigating swiss chard. Performance tests were carried out based on economic and biomass water use efficiencies and cost benefit ratios under two groups of farmers (with and without land). The result showed that the imperforated bar shaped clay pots were found to be suited to grow Swiss chard. The water seeps out through the micro pores of the clay pots with relatively slow leaks and long surface wetting time and large area converge around the roots of plants. Contrarly, perforated clay pots leak the water fast through the macro and micro pores and have relatively short wetting time and small area coverage. On the other hand, the difference between imperforated bar and round types were simply the shapes of the pots which is to do with the area coverage along with the rows of the Swiss chard plant. Round types were not as suitable as bar type of the same capacity for row Swiss chard crops due to their small wetting area coverage compared to a similar volume with imperforated bar shaped clay pots type. The economic and biomass water use efficiency for the imperforated bar clay pot design was higher than that of the bucket irrigation system as well as other tested clay pots. The other advantages with imperforated bar clay pots over the bucket type is that the water source is inside the soil thus evaporation is almost nil and there is also less probability of occurrence of leaf disease due to watering and ultimately improving the biomass and economical water use efficiency. However, the technology was not as profitable as the bucket irrigation technique when considering the benefit-cost ratio (BCR) due to costs incurred for purchase of clay pots.