Fertility status and management implications of wetland soils for sustainable crop production in Akwa Ibom State, Nigeria

Abstract

Fertility status of soils of three wetland types in Akwa Ibom State, Nigeria, was investigated. The wetland types are Inland Valley (IV), Flood Plain (FP) and Mangrove (MG). The soils have silt-clay ratios above 0.15 and 0.25 indicating that they are of young parent materials with low degree of weathering and possible weatherable minerals for plant nutrition. The pH of the soils was near neutral ([6.4) when wet but extremely acid ([3.5) when dried indicating that the soils are potential acid sulphate soils. Organic matter content was high with mean values of 12.59, 6.03 and 3.20% for IV, FP and MG soils, respectively. Total N (nitrogen) was low except in IV soils where the value was above the 0.30% critical level. The C:N ratios were narrow with mean of 20.90, 12.17 and 12.12 for IV, FP and MG soils, respectively. The contents of basic cations [Calcium (Ca), Magnesium (Mg), Potasium (K) and Sodium (Na)] were low while acidic cations [Aluminium (Al) and Hydrogen (H)] were high. The Ca:Mg ratios were below the optimum range of 3:1 to 4:1 required for most crops. The Mg:K ratios were above 1.2, below which yields of crops like corn and soybean may be reduced. Effective cation exchange capacity (ECEC) was below the 20 cmol/kg. Percent base saturation was low (\38) indicating that the soils are potentially less fertile. Exchangeable Al and percent Al saturation were high, above 60% in IV and FP soils. Electrical conductivity was above the critical value of 2 dsm -1 while exchangeable sodium percentage was less than 15. Available Phosphorus (P) and low,\10 ppm and free Fe 2 O 3 /clay ratios were \0.15. Positive correlation existed between silt and ECEC, implying that silt contributed to nutrient status of the soils. Generally, fertility status of the soil is low and would require maintenance of adequate organic matter, application of lime and organic and inorganic fertilizers, drainage and irrigation if the land is to be used for intensive/sustainable crop production.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.

Soil composition and plant nutrients at the interface between crops and saline wetlands in arid environments in NE Spain

“…The CEC of the agricultural soils is below the value reported by Garrido (1994) as indicative of a poor soil for crop production (20 cmol+ kg -1 ). The low to moderate cation exchange capacity of the studied soils (2.4 -14.2 cmol + kg -1 ) is similar to that observed in other saline wetland soils with a very low clay content (Edem and Ndaeyo, 2009), about 11-16 cmol + kg -1 . The high percentage of sand-sized grains in the studied soils conditions their low CEC values and, as a consequence, there is reduced nutrient fixation (Scotney and Dijkhuis, 1990;Gaines and Gaines, 1994;Abe et al, 2009).…”

“…The total N content of the halophytes soils (1.0 -1.6 g kg -1 ) is similar to that obtained in the corresponding cereal-cropped soils, but slightly lower than the values reported in other saline wetlands (1.6 to 4.1 g kg -1 ; Edem and Ndaeyo, 2009).…”

“…Also, from the point of view of agricultural production, soil fertility has been investigated in wetlands, due to interest in rice cultivation (Seneviratne et al, 1994;Buri et al, 1999;Edem and Ndaeyo, 2009;Wang et al, 2011), and submerged soils (Sahrawat, 2015). The variability of the physical and chemical soil properties of interest in agriculture has been investigated under different crop…”

Soil Morphology, Physico - Chemical Properties and Classification of Typical Soils of Mwala District, Kenya

“…The availability of nutrients for uptake by plants depends not only upon absolute levels of nutrients but also on the nutrient ratios [47]. Nutrient imbalances influence nutrient uptake by inducing deficiencies of nutrients which may be present in the soil in good quantities [47]. It is therefore important to consider the individual nutrient ratios i.e.…”

Soil Morphology, Physico-chemical Properties, Classification and Potential of Selected Soils in Kenya

“…The availability of nutrients for uptake by plants depends not only upon absolute levels of nutrients but also on the nutrient ratios [1,31]. Nutrient imbalances influence nutrient uptake by inducing deficiencies of nutrients that may be present in the soil in good quantities [31]. It is therefore important to consider the individual nutrient ratios i.e.…”