Modeling Soil Erosion, Fertility Mining, And
Food Import Quality Enforcement: The Case
Of Wheat In Northern Tanzania
NKONYA, E. M.
4 Pilkington Road, Colline House 3rd Floor
P.O. Box 28565
Kampala
Uganda
Phone: 256-234-41-613 (Business)
256-41-266-185 (Residence)
256-77-451-672 (Cellular)
Fax: 256-41-234-614
E-Mail: nkonya@infocom.co.ug |
Abstract. This research develops a soil conservation model
for smallholder farmers who apply little or no fertilizer. Empirical results
drawn from northern Tanzania imply that ignoring the fertility mining problem
in model specification leads to overestimation of profits for farms that
use little or no fertilizer. Wheat cultivation in the Hanang wheat
complex, northern Tanzania erodes an average of 11 mm of soil each year.
Soil fertility mining averaged 22.2 kg of nitrogen/ton of wheat.
Consequently, wheat yields in the HWC have been decreasing annually.
The effectiveness of pricing policies that may encourage farmers to adopt
soil conservation methods depends on the curvature of the soil erosion
function. When the erosion function is convex, increase in output
price is likely to encourage farmers to adopt soil conservation technologies.
However, when the soil erosion function is concave, increase in output
price may lead to more soil erosion. Since fertilizer prices have been
increasing, increased research funding for alternative sources of industrial
fertilizer may reduce the current rate of soil degradation in northern
Tanzania.
Part II of this research examined the international trade for foods
with uncertain quality attributes. The relative effectiveness of the following
policy instruments are discussed: enforcement of import quality, penalty
to firms importing poor quality foods, and
tariff on imported foods. It is shown that enforcement is the
most effective instrument for reducing importation of poor quality foods.
This implies, for the government of Tanzania to check the current upward
trend of importation of poor quality foods, it needs to increase its current
efforts of enforcing the quality of imported foods. |
