EVALUATION OF THE CAUSES OF SOIL DEGRADATION AROUND A TOWNSHIP WATER TREATMENT PLANT AT AJIWA IN KATSINA STATE, NIGERIA

EVALUATION OF THE CAUSES OF SOIL DEGRADATION AROUND A TOWNSHIP WATER TREATMENT PLANT AT AJIWA IN KATSINA STATE, NIGERIA

Abstract:

A study was initiated to determine the causes of soil degradation of the Ajiwa downstream irrigated lands, resulting from the use of contaminated water of River Tagwai for irrigation, to which was discharged effluent waste sludge from the Ajiwa township water treatment plant in Katsina State, and to proffer possible strategies for good soil and water management of the degraded soils. Soil and water samples were taken at predetermined points along a 5 km stretch of River Tagwai, from Ajiwa dam towards Makurda village, for the determination of relevant parameters in the laboratory. Data were analysed using the SAS statistical package. Mean separation was by LSD and DMRT. Results of the study showed that clay deposition was higher at the point of effluent discharge and decreased with distance, indicating the high impact of the deposits on soil texture and on the soil reaction. The soil pH varied from 4.8 at the point of discharge to 6.4 at distances away, implying that the effluent was acidic, with the attendant effects of acidity on soil processes. Phosphorus fixation was higher at the more acidic proximal sections of the river course. Soil fertility was rated low, and was substantially enriched by the effluent waste deposits up to 2 km, with 70% resulting from this modification, and only 30% of fertility ascribed to the native fertility. However, the chemicals used in the treatments for water purification, (allum (Al(SO4)3.14H20); superfloc; hydrated lime, high test hypochloride and chlorine) influenced the soil conditions significantly resulting in the salinity and sodicity of the soils. White salt deposits on the soil surface as a result of capillary movement of soluble salts at periods of dry spell, were derived from the effluent sludge and comprised essentially of MgSO4, Na2SO4, Na2CO3 and NaCl. These salts are the principal causes of salinity of irrigated lands. Soil and water quality of the study site were poor and could result in the development of sodium hazard when the water is used continuously for irrigation. The values and effects of EC (0.20 dSm-1), SAR (39.35) and ESP (18.15% as well as TDS (20,000 mg L-1) were discussed. It was inferred from the study that the cause of soil degradation was high salinity and sodicity, and the soils should therefore be treated as a case of salt-affected soils. Three strategies were suggested for good soil and water management of these degraded soils: filtration and cationic resin treatment of the effluent for anion exclusion before effluent sludge is discharged, tube well technology and the use of cultural practices for the reclamation of salt-affected soils

EVALUATION OF THE CAUSES OF SOIL DEGRADATION AROUND A TOWNSHIP WATER TREATMENT PLANT AT AJIWA IN KATSINA STATE, NIGERIA

Sharing is caring!