Modelling Water Productivity of Selected Grain Crops in Rain-fed and Surface Irrigated Fields in Northern Nigeria

Field trials of selected grain crops (rice, wheat and maize) were conducted for three years under rain-fed and surface irrigated systems to evaluate their water productivity and model same. A completely randomized design (CRD) experiment was used at the Irrigation Research Station, Kadawa, Kano State. Rice yield was 11.6, 9.9 and 5.3 tons/ha; wheat yield was 1.46, 1.92 and 2.0 tons/ha, while Maize yield was 0.8, 0.4 and 0.91 tons/ha in the 2009/2010, 2010/2011 and 2011/2012 cropping season, respectively. ANOVA revealed a highly significant difference in the yield of paddy rice, wheat and maize at both 1 % and 5% significant levels (Fcalc>Ftab), with p-value of 0.0002, 0.004 and 0.001 for rice, wheat and maize respectively. Crop – water productivity models developed revealed that optimum crop yield of 12.8 tons/ha of paddy rice, 2.7 tons/ha of wheat and 0.94 tons/ha of maize is achievable with 58.3 cm of rainfall, 34 cm and of 29.8 cm of irrigation water respectively

Evaluation of chloride mass balance and recharge in agricultural lands in Nigeria

Groundwater salinization studies and recharge estimation was carried out at the Irrigation Research Station, Kadawa, Nigeria. Groundwater samples from fifteen randomly selected piezometer locations were analyzed monthly for chloride using Mohr’s method for three years while recharge was estimated using the chloride mass balance (CMB) method. Groundwater chloride range from 22 - 91.4 mg/l, seasonal trend was identified with the hot dry season (April – June) having higher values than the wet season (July – October). Correlation analysis revealed chloride status that is not associated with one another in all soil types while salt build up was observed at the south western tip of the farmland indicating potential reduction of agricultural productivity. CMB revealed a mean annual recharge of 869 mm; the method was found to underestimate recharge because it does not account for lateral flow contribution, hence should be discouraged as a stand-alone methodology for recharge studies. Salt build-up was exacerbated by the collapse of the drainage system. Reconstruction of the drainage systems using tile drains should be executed to control the rising water level in the area; conjunctive use of groundwater and surface water is recommended to maximally utilise available water in order to ensure ecological sustainability and free some water for other uses

Assessment of the Effect of Land Use /Land Cover Changes on Total Runoff From Ofu River Catchment in Nigeria

The total runoff from a catchment is dependednt on both the soil characteristics and the land use/land cover (LULC) type. This study was conducted to examine the effect of changes in land cover on the total runoff from Ofu River Catchment in Nigeria. Classified Landsat imageries of 1987, 2001 and 2016 in combination with the soil map extracted from the Digital Soil Map of the World was used to estimate the runoff curve number for 1987, 2001 and 2016. The runoff depth for 35 years daily rainfall data was estimated using Natura Resource Conservation Services Curve Number (NRCS-CN) method. The runoff depths obtained for the respective years were subjected to a one-way analysis of variance at 95% level of significance. P-value < 0.05 was taken as statistically significant. Runoff curve numbers obtained for 1987, 2001 and 2016 were 61.83, 63.26 and 62.79 respectively. The effects of the changes in LULC for 1987-2001, 2001-2016 and 1987-2016 were statistically significant (P<0.001) at 95% confident interval. The average change in runoff depths were 79.81%, -11.10% and 48.09% respectively for 1987-2001, 2001-2016 and 1987-2016. The study concluded that the changes in LULC of the catchment had significant effect on the runoff from the catchment

Performance evaluation of selected infiltration equations for irrigated (FADAMA) soils in Southern Kaduna Plain, Nigeria

ABSTRACT The need for continuous and in-depth study on the applicability and accuracy of infiltration equations cannot be exhausted since equation parameters and performance vary for different soils. The study reported herein, has evaluated four infiltration equations (Kostiakov's; Philip's; Horton; Talsma and Parlange). The field water infiltration data used in these equations were based on double ring infiltrometer tests conducted for 4 hours at two fadama irrigation area (Kuda and Kukumdaji). Measurements were made at two sites in each of the two Fadama irrigation area based on land management practice (Cultivated/fallow) giving a total of four experimental sites. The results of the measured infiltration rates reveals that site 2 (Kuda/fallow) gave the highest average final infiltration rate of 69mm/hr followed by site 1(Kuda/cultivated) of value 52mm/hr and then site 3(Kukumdaji/cultivated) of value 35mm/hr while site 4 (Kukumdaji/fallow) recorded the least of 18mm/hr. Results of the Comparism between measured and predicted infiltration rates reveal that Kostiakov's and Philip's equation gives the best fit when compared with the rest of the equations tested. Results from the study conclude that Kostiakov's and Philip's equation can be used to predict infiltration rates for the soil studied but that Kostiakov's equation approximated the measured infiltration rates with higher accuracy and best fit than did Philip's and Horton's equation. Talsma and Parlange's equation fail to approximate measured data particularly in the early stage of measurement

Groundwater dynamics and recharge trends in semi-arid irrigated lands of Nigeria

Groundwater dynamics and recharge trends were evaluated for three years (2008 – 2011) to elucidate the daily, monthly and seasonal response to climate and irrigation. Observed water levels ranges between 120 – 1180 mm, below ground level (b.g.l.) in the identified soil profiles in the area; a good correlation of water level exist in the area despite differing soil profile types and nonuniform irrigation regime in the dry season. Analysis for trend, change and randomness reveals high diurnal variations in the cool dry season, hot dry season and wet season. Exponential smoothing model was found to adequately predict groundwater recharge and discharge in the area. A new cropping schedule was proposed to forestall low crop yields caused by the new groundwater regime

Analyses of the Hydraulic Performance of a Continuous-Flow Drip Irrigation System Tested on a Tomato Field in Bauchi, Nigeria

A low-cost, low-tech continuous flow drip irrigation system was constructed and tested in Bauchi. The measured hydraulic performance parameters were analysed using computer based regression, correlation and path analyses. Results showed that the total flow energy of the system is most sensitive to variations in pressure energy. Without flow regulation, fluctuation in the system discharge is influenced largely by plugging and hydraulic design parameters. However, flow regulation using ‘Medi emitter’ cushions discharge variations caused by hydraulic design. This leaves variation due to plugging as the sole source of discharge fluctuation with the system. A set of regression equations is equally provided for speedy design and evaluation of similar drip systems under same operating conditions. The set of regression equations in particular, includes a systems specific form of the Bernoulli’s Equation that may be used for computations of flow energy requirements. Inferences from the regression analysis revealed that the maximum practicable lateral length of the continuous-flow drip system is 4.6 m

Hydrologic and Morphometric Analysis of Ofu River Sub-Basin using Remote Sensing and Geographic Information System

The morphometric characteristics of a river basin are very important factors in watershed hydrology. The morphometric analysis of the Ofu River sub-basin was carried out in this study to assess its morphologic and hydrological characteristics as well as its flood potentials based on the morphological characteristics. The study was carried out using remotely sensed spatial data analysed using Geographical Information Systems (GIS). The morphometric parameters analysed were the areal, linear, and relief aspects of the sub-basin. The results showed that Ofu river sub-basin covers a total area of 1604.56 km2 and a perimeter of 556.98 km covering parts of Kogi and Enugu States in Nigeria. The sub-basin has 3rd order river network based on the Strahler’sclassification with a dendritic drainage pattern and moderate drainage texture. The values of bifurcation ratio, drainage density, circularity ratio, elongation ratio, form factor, stream frequency and drainage intensity indicate that the sub-basin is elongated and would produce a flatter peak of direct runoff for a longer duration implying that the sub-basin is morphometrically less susceptible to flood and that any flood flow that may emanate from it would be easy to manage

Development of Rating Curve for Ofu River at Oforachi Hydrometric Station

The stage-discharge rating curve is widely used in the research for analysis of flow regime and design of hydraulic structure and river channel where the measurement of discharge is difficult especially in developing countries like Nigeria. This study sought to develop a stage-discharge relationship for Ofu River in Nigeria where water resources project planning has been limited by the unavailable of stream flow data. Discharge Measurement was carried out using Valeport Current meter while stage was measured using staff gauge at Oforachi Bridge hydrometric station from February, 2016 to January, 2017. The Stage and discharge results were used to determine the curve coefficient via regression analysis and finally the rating curve equation for the river at this station. The Oforachi Bridge serves as the permanent control, thus the curve is reliable

Hydrologic and Morphometric Analysis of Ofu River Sub-Basin using Remote Sensing and Geographic Information System

The morphometric characteristics of a river basin are very important factors in watershed hydrology. The morphometric analysis of the Ofu River sub-basin was carried out in this study to assess its morphologic and hydrological characteristics as well as its flood potentials based on the morphological characteristics. The study was carried out using remotely sensed spatial data analysed using Geographical Information Systems (GIS). The morphometric parameters analysed were the areal, linear, and relief aspects of the sub-basin. The results showed that Ofu river sub-basin covers a total area of 1604.56 km2 and a perimeter of 556.98 km covering parts of Kogi and Enugu States in Nigeria. The sub-basin has 3rd order river network based on the Strahler’s classification with a dendritic drainage pattern and moderate drainage texture. The values of bifurcation ratio, drainage density, circularity ratio, elongation ratio, form factor, stream frequency and drainage intensity indicate that the sub-basin is elongated and would produce a flatter peak of direct runoff for a longer duration implying that the sub-basin is morphometrically less susceptible to flood and that any flood flow that may emanate from it would be easy to manage