Land Quality and Agricultural Productivity: A Distance Function Approach
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productivity with respect to the unrestricted frontier; that is, equation (6) divided by the first term
of equation (6).
For the countries with higher land quality, the productivity value differs very little
between the unrestricted and restricted measures. For countries with lower land quality, the
measures diverge. The divergence can be either negative or positive, depending on whether the
first term of equation (6) is greater than or less than one. Some countries, primarily sub-Saharan
African countries, experience a switch from positive productivity to negative productivity (Cote
D’Ivoire, Ghana, Cameroon, Tanzania, Sierra Leone, N. Korea, Ethiopia, Lesotho, Senegal,
Kenya, Mali, Botswana, Afghanistan, Algeria and Egypt). This implies that poor land quality is
impeding productivity growth. Other countries show changes from negative productivity to
positive productivity (El Salvador, Indonesia, Guinea-Bissau, Angola, Nepal, Mozambique and
Niger).
CONCLUSIONS
Land quality is an important factor affecting agricultural efficiency, and as a consequence, the
productivity of agriculture over time. The importance of this factor, as one would expect, is
greatest in countries with the poorest land quality. At the farm scale, poor soil and grazing land
reduces potential crop yields and livestock productivity, limiting both production and income.
At the country level, poor land quality translates to lower agricultural output than in non-limited
environments, limiting the ability to feed growing populations (whether through domestic
production or commercial imports).
Because land quality varies both within and between countries and is largely
uncontrollable in the short term, productivity measures for countries with poor land quality may