Characterisation and Soil Pollution in Agrarian Floodplain of Ibadan Peri-Urban in South Western Nigeria

Ibadan metropolis in Nigeria has population of about 6millons people. There is increasing concern about lowland soils around Ibadan periurban where most of the industrial wastes transported  majorly by River Ona were deposited. These soils are used for dry season farming and  contribute to food security. This research was carried out to characterise and  determine the vulnerability of periurban lowland  soils to industrial pollution . The area was studied using 50mx50m  grid. Surface samples were taken at 50m interval. Representative profile pits were dug and described using USDA method. Particle size analysis and chemical analyses including Phosphorus, Nitrogen , exchangeable Cations (Ca, Mg, Na, K,),  Mn and heavy metals such as Pb. Cu, Zn, Cr, Fe, Cd determinations were carried out. The results shows that the surface soil of the flood plain was fertile with high N (0.35cmol/kg), P (51.25 cmol/kg), K (0.61 cmol/kg) with very high to toxic levels of phosphorous in the soil which range between 28.99 to 87.70 ppm. Average lead concentration was (34.30 mg/kg), Zn (171.20 mg/kg), Fe (83.97 mg/kg), Cu (19.11 mg/kg), Mn (31.10 mg/kg), Cr (0.69 mg/kg), Cd (0.3 mg/kg). The predictions from soil-plant heavy metal transfer coefficient (Pb:35-343; Cr:0.46-4.6; Zn:171-1712; Cu:19-191; Fe:83-840; Mn:31-281; Cd:0.1-10)  shows that there might be toxic level in crops in the area but the high yield and health of plant from field evidence and farmers interaction indicate that the  high level of P (28.99-87ppm) must have inhibited uptake of some metals such as Pb, Zn and Cu. Keywords: Fadama, Urban waste, Heavy metals, Soil pollution, Peri-urban farmin

Status of integrated soil fertility management (ISFM) in southwestern Nigeria

Published online: 8 March 2017The soils of South western Nigeria are rapidly degrading due to nutrient mining, soil loss, inappropriate land use, low inherent soil fertility coupled with adverse effects of climate change. These have resulted to persistent low yields and farmers’ poverty. The current farming systems have failed to improve continuous decline in crop production. There is need for integrated approach that involves mineral fertilizer, organic resources, and improved crop varieties with sound agronomic practices if the region will be able to feed its population of over 35 million people. Integrated Soil Fertility Management (ISFM) is an all-encompassing resource management technique that embraces the use of good planting materials, with appropriate organic and/or inorganic fertilizer application or their integrated use. It also entails adapting the various combinations of the ISFM components to local conditions which by implication means site specific management. There is lack of coordinated information about the components of ISFM being used in SWN and most stakeholders have not appreciated the importance of integrated approach. This paper is therefore put forward to review the status of Integrated Soil Fertility Management in South western Nigeria in order to identify knowledge gap for sustainable crop production in the region