Tobacco Cultivation Effects on Soil Fertility and Heavy Metals Concentration on Smallholder Farms in Western Kenya

Kisinyo Peter Oloo

 

Full Length Research Paper I Published June,2016

 

Journal of Agricultural Science and Food Technology  Vol. 2 (5), pp.75-79.

 

 

ABSTRACT

 

This study was conducted to determine the effect of tobacco cultivation on soil fertility status (pH, nitrogen (N), phosphorus (P), potassium (K) and organic carbon (OC)) and heavy metals (cadmium (Cd), lead (Pb), cobalt (Co), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni) and zinc (Zn)) concentration on selected smallholder tobacco farms and virgin lands in Migori County, Kenya. Tobacco farms had low soil fertility (pH; 4.3-5.29, N; 0.04-0.16%, Olsen P; 4.3-7.4 mg/kg, OC; 0.54- 0.21% and exchangeable K⁺; 0.3-0.8 cmol/kg) than virgin lands (pH; 5.7-6.5, N; 0.16 - 0.29%, Olsen P; 6.8-9.4 mg/kg, OC; 2.24-3.80% and exchangeable K⁺; 0.5-1.6 cmol/kg). Tobacco farms had higher heavy metals concentration (Cu; 1.02-2.1; Pd; 1.01-2.6, Cr; 0.58-1.03, Zn; 0.32-1.02; Mn; 0.33-0.99, Ni; 0.55-1.09; Cu; 1.07-2.31 and Co; 1.02-2.31 µg/g soil) than virgin lands (Cu; 0.05-0.29; Pd; 0.03-0.19, Cr; 0.45-0.95, Zn; 0.29-0.99; Mn; 0.29-0.9, Ni; 0.39-0.9; Cu; 0.35-0.98 and Co; 0.22-0.49 µg/g soil). All tobacco farms had Cd, Pb, Cu and Co contamination while the levels of Zn, Cr, Ni and Mn were below the maximum permissible limits. Therefore, tobacco production leads to soil fertility depletion and heavy metals contamination in soils.

Key Words: Soil, fertility depletion, heavy metal concentrations, tobacco.
 

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