Thin on the Ground

Land Resources: Now and for the Future






363 000 people were born

154 000 died

World population increased by 209 000

Annual world population increase:
2008 77 M, 2009 80 M, 2010 78 M, 2011 76 M



Spare land? A challenge to official estimates

A series of estimates by FAO and other international organizations have identified a 'land balance', land that is cultivable but not presently cultivated, for developing countries, of about 1600 million hectares. The supposed existence of this spare land is widely quoted in forecasts of capacity to reduce present hunger and food requirements of future population increase.

This view has recently been challenged. In an article Is there really spare land? Anthony Young argues that official figures, obtained by subtracting data on present cultivation from estimates of cultivable land, greatly over-estimate the land balance.

The impression given by current estimates, that a reserve of spare land exists, is misleading to world leaders and policy makers. It reduces the urgency for better funding of agricultural research, and more development in the rural sector. Above all, it misleads those with the power to influence policy over the urgency of stronger action to check population increase.

Basis of the challenge

What is this challenge based upon? Primarily, personal observation in many developing countries. Is there really a land balance (cultivable minus cultivated) of about 50% in Vietnam, Jamaica, Kenya, Malaysia and Ethiopia? . And what about the 80-90% land balances quoted for Tanzania, Sudan, Madagascar, Zambia and Venezuela? There would certainly be an outcry if the land balances of Malaysia and Venezuela, almost entirely under rain forest, were cut down for farming.

If there is so much spare land, why has cultivation so often been extended onto steep slopes (e.g. Jamaica) or into semi-arid regions with high drought risk (e.g. Kenya, the sahel zone of West Africa)? Why are farm sizes so small, and why is poor land cropped continuously?

Malawi is cited as a test case. Average farm size there is now below 0.5 hectare. Under-nutrition is endemic. A recent field tour found that in two thirds of the country there is virtually no spare land to be seen, whilst in the Northern Region, land currently being taken into cultivation is steeply sloping, and being farmed in ways which are non-sustainable.

Reasons for the over-estimates

Four reasons for the incorrect official estimates are given:

  • Over-estimation of cultivable land. The Soil Map of the World, used to estimate cultivable land, ignores substantial inclusions of hills, swamps, rocky land, etc.
  • Under-estimation of present cultivation. Data on land use are the least reliable of international statistics. Governments often ignore illegal cultivation, e.g. in forest reserves.
  • Under-estimation of land required for settlement and other non-rural uses.
  • Failure to allow for forest, woodland and pasture on cultivable land.

A speculative adjustment

A speculative adjustment to official figures is suggested, taking a hypothetical country with a supposed gross land balance of 50%. Mean, minimum and maximum adjustments are suggested. Taking 1000 ha as a basis, the mean adjustments are:

  Original estimate Proposed mean adjustment
Cultivable 1000 875
Cultivated 500 575
Gross balance 500 300
Protected land 60 36
Settlement 15 16
Intermediate balance 425 248
Forest, pasture nil 131
Net balance 425 117
Net balance as % of original estimate of cultivable land 42.5%

12% (range between min. and max. adjustments: 3-20%)

Thus, an original gross land balance of 50% is reduced to a realistic area of between 3% and 20%.

Testing the challenge

A simple and direct means to test this challenge is proposed: locate, and if possible map, the supposed spare land. In outline, observers would go to the regions of a country where spare land is believed to exist, and ask to be shown it in the field. They would then determine:

  • Is the land in fact cultivable, sustainable and without degradation?
  • Is it in reality not yet cultivated?
  • Is it already in use for other necessary purposes (e.g. strategic water catchments, support for indigenous peoples)?

Research of this kind could be carried out by consultants, visiting sample countries and working with national land resource survey organizations. Still better, any national organization (Soil Survey, Land Use Planning Department, etc.) could directly undertake to estimate the available land in their own country.

Your own experience

How does your experience match up with official estimates? Look up the figures for countries you know, and compare them your field knowledge. The current FAO estimates can be found on TERRASTAT: select "Actual and potential available arable land" and your region of interest; note especially colum 7, "Percent of potential arable land actually in use".. Comparison may be made with earlier estimates found in World Agriculture: Towards 2010 (ed. N. Alexandratos, Wiley for FAO), Table A.5, p.463.

* * * * *

The above argument was put forward in outline in Chapter 13, Land, food, and people, of Land Resources: Now and for the Future (see pp.240-249).