Author : Sunmonu, M.o., Chukwu, O., Alabadan, A. B., Osunde, Z.d. [ Volume No. : I Issue No. : I - July 2012] [Page No : 22-26] [2012]

A study was conducted on the impact of soil inter-space bulk density and moisture content on the vitamin A content of stored oranges in passive evaporative cooling structures. Two sets of four different types of passive evaporative cooling structures made of two different materials, clay and aluminium were constructed. One set consists of four separate cooling chambers. Two cooling chambers were made with aluminium container (round and rectangular shapes) and the other two were made of clay container (round and rectangular). These four containers were separately inserted inside bigger clay pots and lateritic walls inter- spaced with clay soil of 5 cm (to form tin-in-pot, pot-in-pot, tin-in-wall and wall-in wall) with the outside structure wrapped with jute sack. The other set followed the same pattern with interspacing of 10 cm. The two sets (5 cm and 10 cm interspaced soil) were constantly wetted with salt solution (sodium chloride, NaCl)) at intervals of between 2 to 4 hours depending on the rate of evaporation to keep the soil in moist condition. In addition, the control has no fans and the inner cooling chambers were not lined with polyethylene nylon while the other two sets have fans and their inner cooling chambers lined with polyethylene nylon Freshly harvested oranges were used for the experiment and the inter-space soil bulk density, soil moisture content and vitamin A content of stored oranges were determined at interval of three days for a period of three weeks. The interspace soil bulk density values of 0.98 g/cm3, 1.6 g/cm3, 0.91 g/cm3, 0.98 g/cm3, 0.99 g/cm3, 0.97 g/cm3 and 0.92 g/cm3 with the soil moisture contents values of 78.4%, 81.58%, 82.56%, 79.12%, 79.68%, 79.74% and 79.74% were recorded for the 5 cm structures. Also the interspace soil bulk density values of 1.42 g/cm3, 1.21 g/cm3, 1.34 g/cm3, 1.00 g/cm3, 0.98 g/cm3, 0.98 g/cm3 and 0.97 g/cm3 with the soil moisture contents values of 78.73%, 79.17%, 78.18%, 78.34%, 82.54%, 81.79% and 81.36% were recorded for the 10 cm structures