SOIL PHYSICAL AND CHEMICAL PROPERTIES AND CROP WATER REQUIREMENT OF SOME SELECTED VEGETABLE CROPS AT CENTRAL EXPERIMENTAL FIELD OF URBAN FOOD PLUS PROJECT IN SANARIGU DISTRICT, TAMALE, GHANA

Abstract

This study was carried out to determine the crop water requirement of some selected vegetable crops cultivated at the Central Experimental Site for Urban Food Plus Project. These crops include `Ayoyo` (Corchorus spp), Lettuce (Lactuca sativa), Cabbage (Brassica oleracea), Amaranthus (Amaranthus candatus) and Carrot (Daucus carota). Crop water requirement for each of the crops was determined by using 30-year climatic data from the Tamale Synoptic station as and input in CROPWAT programme, FAO, version 8, 2014. Using CROPWAT, Reference Evapotranspiration (ETo) was determined using the FAO Penman Monteith method. For all the crops, daily, decadal and seasonal crop and net irrigation requirements were computed for the various growth stages: initial, development, mid-season and late season. The soil infiltration test was conducted in situ while composite soil samples were also collected for laboratory analysis of some soil physico-chemical properties of the experimental site. The study shows that the soil was low in organic matter content, slightly acidic, but not saline and also has low water holding capacity due to its low amount of clay content. The site however, is well drained and is therefore suitable for cultivation of vegetables and upland arable crops. Climate conditions, however demand considerable amount of irrigation to supplement rainfall in the period mid- November to March, when the experiment was taking place. Reference Evapotranspiration (ETo) varied from 3.9 mm / d in August to 8.9 mm / d in February. Crop evapotranspiration (ETc) for `ayoyo` varied from 4.03 to 8.81 mm / d, for cabbage from 4.03 to 9.43 mm / d, for lettuce from 4.03 to 9.19 mm / d, for carrot, 4.03 to 10.53 mm / d, for amaranthus from 4.03 to 9.75 mm / d. Thus, with the calculation of crop water requirement and net irrigation demand for each of the crops cultivated, an appropriate water planning and management can be scheduled to ensure that adequate soil water is maintained by rainfall and/or irrigation, so that it does not limit plant growth and crop yield.