Evaluation of water quality of tube wells in Sokoto-Rima floodplains for irrigated rice production

Abstract

Evaluation of water quality of tube-wells for irrigation purpose in Sokoto-Rima floodplains along Rima river in Kwalkwalawa village was conducted. Water samples were collected from 10 randomly selected tube-wells. Irrigation water quality were assessed in the laboratory based on most important water quality parameters according to FAO and some selected important trace elements. All tube-wells evaluated in the area were observed to be 2 inches in size. The results of the laboratory analysis for the Electrical Conductivity (EC), Total Dissolved Solids (TDS) and Sodium Adsorption Ratio (SAR) of all the water samples were low, except the values of SAR of tube-wells at point C and E, whose values exceeds >13, thus, may pose a threat to irrigation. The pH of the tube-well water ranges from 6.33 to 7.45, indicating slightly acidic to slightly alkaline. The values of Carbonates, Bicarbonates, Mg, Ca, Na, Nitrates, Sulphates and Chlorides were all below the critical limits and are considered safe for irrigation. Also, the value of all micro-nutrients such as Boron, Fe, Zn, Mn and Ni were all considered safe. In conclusion, caution must be taken for the extreme values of Na and SAR in the irrigation water, which may cause threat to both the soil and crops in near future, when used continuously. Periodic evaluation of both the soil and irrigation water should be encouraged and appropriate management practices such as planting of crops that are highly tolerant to Na, deep tillage, periodic application of gypsum and incorporation of organic matter and crop residues after harvest should be encouraged.