ABSTRACT
Pitchers, in their simplest form, consist of unglazed baked earthen pots, which are buried to their neck in the soil and filled with water, directly feeding the roots of the plants with a steady supply of moisture. Pitcher irrigation system is one of the most efficient traditional irrigation systems. Water seeps out of a buried pitcher due to the pressure head gradient across the walls of the pitchers directly into the root zone of the irrigated crop. The pressure gradient results from positive pressure head inside the pitcher and negative pressure head on the outer surface of the pitcher which is in contact with the soil. The experiment was conducted to determine ways of reducing the volume of water use in crop production in the study area. Two sets of pitchers, one set 10mm thick (six in number, replicated three times) and the other set 15mm thick (six in number, replicated three times) were constructed, with each pitcher having a varying proportions of sand or sand and sawdust incorporated into the clay during construction, to enhance the release of moisture into the surrounding soil, and each pitcher also serves as a treatment in the experiment. All the pitchers have a depth of 24cm and an internal diameter of 28cm. The capacity of the pitchers is approximately 12 litres (12,000cm3). Results from the experiment show that, the amount of water released by the 1.0cm thick pitchers (6.75a) is significantly higher than the amount of water released by the 1.5cm thick pitchers (5.81b). Pitcher composition also played a significant role in the release of moisture to the crops, where pitchers with 70% clay, 25% sand and 5% sawdust (T11/T12) releases significantly higher volume of water (7.68b) than all the other pitcher compositions. Significantly higher yield was produced by treatments T11/T12 (134.32a) over the other treatments. While, significantly lower crop yield was recorded in treatments T1/T2 (88.48b). The average total volume of water used to produce lettuce crop in the experiment is 1,739.4m3/ha and the average yield recorded was 13,843kg/ha. The volume of water use to produce lettuce crop in the experiment is much less than the volume of water use in producing the same crop using both micro sprinkler (2,227m3 /ha) and drip (1,782m3/ha) irrigation systems. The average yield recorded in the experiment is less than that obtained in both micro sprinkler (21,700kg/ha) and drip (18,150kg/ha) irrigation systems. This is as a result of the challenges faced during the conduct of the experiment. Extension and agricultural research institutions should work closely with the farming community in order to identify develop and smoothly promote a range of locally appropriate technological options, such as the clay pitcher irrigation system.