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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:

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:

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.

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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).