Soil factors Influencing the Availability of Manganese in Soils of Agricultural Land-use System in a Coastal Plain Sands of Umudike

Ernest U. Eteng

Department of Soil Science and Meteorology, Michael Okpara University of Agriculture, Umudike, Nigeria.

Author's Email ✉: eteng_em@yahoo.com

Accepted December 19, 2017

The research was conducted in 2017 at the Michael Okpara University Agriculture, Umudike to investigate soil factors influencing the availability of Mn in soils of agricultural land-use systems. Soil samples were collected from two depths (0-20 and 20-40 cm) from five selected land use types; cassava farm, legume fallow, rice farm, forest reserved and grazing fields using a soil auger. Available Mn in the soils was determined using four extractants; Coca-Cola, EDTA, HCl and NH₄OAc. The results showed that, higher mean values of the physical and chemical properties were recorded in the surface (0-20 cm) than in the subsurface (20-40 cm) soil layer and these, were significantly (P <0.05) affected by land use and soil depth. The highest mean value (19.05 mg/kg) and lowest mean value (18.46 mg/kg) of available Mn was obtained from rice farm and cassava farm, respectively. The availability of Mn in the soils under the land use systems and soil depth were considerably varied in the order of Coca-Cola > EDTA > NH₄OAc > HCl. The main concern about the study showed that, EDTA-Mn had significant negative correlation with soil pH (r = -0.732**). HCl-Mn had significant positive correlation with OM (0.739**) but, significant negative correlation with pH (r = -0.842**). NH₄OAc-Mn had significant positive correlation with SOM (r = 743**) but, significant negative correlation with ECEC (r = -0.673). Coca-Cola-Mn had significant positive correlation with SOM (r = 810**) and ECEC (r = 0.827**) but, significant negative correlation with sand fraction (r = 705**) and pH (r = -0.779**). The study indicates that, notable soil properties such as texture, SOM, pH and ECEC significantly influenced the availability of manganese in soils of the study area.

Key words: Coastal plain sand, land use system, Mn, physico-chemical properties, soil depth, Umudike.

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