ABSTRACT

This project work was conducted to determine the soil moisture balance of a sandy loam soil in Umudikc using existing related model, from the month of June to August. The specific objective was to compare the soil moisture balance for three specified months. Daily rainfall data was obtained from National Root and Crop Research Institute (NRCRI) Umudike meteorological station. The evaporation rate was obtained using Class A pan by monitoring daily evaporation fix each month. The measured rainfall was subtracted from the water level reading in the pan to determine the amount of moisture evaporated. A pan crop coefflicient (Kc) was applied to the pan evaporation data to reflect the crop water use (ET_p) through which evapotranspiration was computed. The weekly runoff computation for each month was also determined using runoff curve number (Rcn) which is a function of the soil type, soil infiltration capacity. land use and soil hydrological information obtained from charts. The surface runoff drainage, actual evapotranspiration. field capacity (FC), and permanent wilting point (PWP) were computed. The results of the soil analysis for the study area show that the soil has an average initial moisture content of 19.93mm and bulk density of 1.29g/cm3.The porosity of the soil sample is 2.26% and the average infiltration rate is 16.00mm/h. The results also revealed that the total rainfall for the months of June, July, August were 37 1.2mm, 129.2mm and 305.2mm, respectively. This consequently resulted in the month of June having the highest amount of runoff which is 232.57mm. The drainage pattern has an average value of 3.626mm.The overall moisture balance within the months of study shows that it ranges between 80.2mm 120.22mm for the time of' study. Deriving from the study, one of the major recommendations, being proffered is that. this work will be used in subsequent irrigation scheduling which helps the farmer to know when to irrigate.