Crop production and natural resource use

4.1 Introduction

This chapter discusses the main agronomic factors underlying the projections of crop production presented in Chapter 3. The focus is on crop production in developing countries, for which the projections were unfolded into land and yield projections under rainfed (five land classes) and irrigated conditions. Although the underlying analysis was carried out at the level of individual countries, the discussion here is limited to presenting the results at the level of major regions, which unavoidably masks wide intercountry differences. The parameters underlying the livestock production projections will be discussed in Chapter 5. Selected technology issues such as the scope for further yield increases, technologies in support of sustainable agriculture and the role of biotechnology are discussed in Chapter 11. Issues of environment and the possible impact of climate change on crop production are the subjects of Chapters 12 and 13.

4.2 Sources of growth in crop production

Aggregate crop production at the world level is projected to grow over the period to 2030 at 1.4 percent p.a., down from the annual growth of 2.1 percent of the past 30 years (Table 4.1). For the developing countries as a group, the corresponding growth rates are 1.6 and 3.1 percent p.a., respectively (or 1.8 and 2.7 percent p.a., excluding China). The reasons for this continuing deceleration in crop production growth have been explained in Chapter 3.

The projected increase in world crop production over the period from 1997/99 to 2030 is 55 percent, against 126 percent over the past period of similar length. Similar increases for the developing countries as a group are 67 and 191 percent, respectively. The only region where the projected increase would be about the same as the historical one would be sub-Saharan Africa, namely 123 and 115 percent, respectively. The faster growth in the developing countries, as compared to the world average, means that by 2030 this group of countries will account for almost three-quarters (72 percent) of world crop production, up from two-thirds (67 percent) in 1997/99 and just over half (53 percent) 30 years earlier.

There are three sources of growth in crop production: arable land expansion which, together with increases in cropping intensities (i.e. increasing multiple cropping and shorter fallow periods), leads to an expansion in harvested area; and yield growth. About 80 percent of the projected growth in crop production in developing countries will come from intensification in the form of yield increases (67 percent) and higher cropping intensities (12 percent, Table 4.2). The share due to intensification will go up to 90 percent and higher in the land-scarce regions of the Near East/North Africa and South Asia. The results for East Asia are heavily influenced by China. Excluding the latter, intensification will account for just over 70 percent of crop production growth in East Asia. Arable land expansion will remain an important factor in crop production growth in many countries of sub-Saharan Africa, Latin America and some countries in East Asia, although much less so than in the past. The estimated contribution of yield increases is partly a result of the increasing share of irrigated agriculture in total crop production (see Section 4.4.1), and irrigated agriculture is normally more«intensive» than rainfed agriculture.

The results shown in Table 4.2 should be taken as rough indications only. For example, yields here are weighted yields (1989/91 price weights) for 34 crops and historical data for arable land for many countries are particularly unreliable.¹ Data on cropping intensities for most countries are non-existent and for this study were derived by comparing data on harvested land, aggregated over all crops, with data on arable land. The projections are the end result of a detailed investigation of present and future land/yield combinations for 34 crops under rainfed and irrigated cultivation conditions, for 93 developing countries.² In the developed countries, the area of arable land in crop production has been stagnant since the early 1970s and recently declining. Hence growth in yields and more intensive use of land accounted for all of their growth in crop production and also compensated for losses in their arable land area.

Growth in wheat and rice production in the developing countries increasingly will have to come from gains in yield (more than four-fifths), while expansion of harvested land will continue to be a major contributor to production growth of maize, possibly even more so than in the past (Table 4.3). These differences are partly because the bulk of wheat and rice is produced in the land-scarce regions of Asia and the Near East/North Africa while maize is the major cereal crop in sub-Saharan Africa and Latin America, regions where many countries still have room for area expansion. As discussed in Chapter 3, an increasing share of the increment in the production of cereals, mainly coarse grains, will be used in livestock feed. As a result, maize production in the developing countries is projected to grow at 2.2 percent p.a. against«only» 1.3 percent for wheat and 1.0 percent for rice. Such contrasts are particularly marked in China where wheat and rice production is expected to grow only marginally over the projection period, while maize production is expected to nearly double. Hence there will be a corresponding decline in the wheat and rice areas but an increase of 36 percent in the maize area.

The actual combination of the factors used in crop production (land, labour and capital) in the different countries will be determined by their relative prices. For example, taking the physical availability of land as a proxy for its relative scarcity and hence price, one would expect land to play a greater role in crop production the less scarce and cheaper it is. For the 60 countries out of the 93 developing countries studied in detail, which at present use less than 60 percent of their land estimated to have some rainfed crop production potential (see Section 4.3.1), arable land expansion is projected to account for one-third of their crop production growth. In the group of 33 land-scarce countries - defined here as countries with more than 60 percent of their suitable land already in use - the contribution of land expansion is estimated to be less than 10 percent.

For the developing countries, this study made an attempt to break down crop production by rainfed and irrigated land in order to analyse the contribution of irrigated crop production to total crop production. It is estimated that in the developing countries at present, irrigated agriculture, with about a fifth of all arable land, accounts for 40 percent of all crop production and almost 60 percent of cereal production (Table 4.4). It should be emphasized that, apart from some major crops in some countries, there are only very limited data on irrigated land by crops and the results presented in Table 4.4 are almost entirely based on expert judgement (see Appendix 2 for the approach followed in this study). Nevertheless, the results suggest an increasing importance of irrigated agriculture, which accounts for a third of the total increase in arable land and for over 70 percent of the projected increase in cereal production.

4.3 Agricultural land

At present some 11 percent (1.5 billion ha) of the globe's land surface (13.4 billion ha) is used in crop production (arable land and land under permanent crops). This area represents slightly over a third (36 percent) of the land estimated to be to some degree suitable for crop production. The fact that there remain some 2.7 billion ha with crop production potential suggests that there is still scope for further expansion of agricultural land. However, there is also a perception, at least in some quarters, that there is no more, or very little, land to bring under cultivation. In what follows, an attempt is made to shed some light on these contrasting views by first discussing the most recent estimates of land with crop production potential and some constraints to exploiting such suitable areas (Section 4.3.1). Then the projected expansion of the agricultural area during the next three decades (to 2030) is presented in Section 4.3.2, while Section 4.3.3 speculates about whether or not there will be an increasing scarcity of land for agriculture.

4.3.1 Land with crop production potential for rainfed agriculture

Notwithstanding the predominance of yield increases in the growth of agricultural production, land expansion will continue to be a significant factor in those developing countries and regions where the potential for expansion exists and the prevailing farming systems and more general demographic and socio-economic conditions favour it. One of the frequently asked questions in the debate on world food futures and sustainability is: how much land is there that could be used to produce food to meet the needs of the growing population? Since the late 1970s, FAO has conducted a series of studies to determine the suitability of land for growing various crops. Recently, a new study was undertaken together with the International Institute for Applied Systems Analysis (IIASA) to refine the methods, update databases and extend the coverage to all countries in the world by including also countries in temperate and boreal climates, which were previously not covered. A summary description of the method is given in Box 4.1 and a full description and presentation of results can be found in Fischer, van Velthuizen and Nachtergaele (2000).

Table 4.5 gives some results for selected crops and input levels. At a high input level (commercial farm operations, see Box 4.1), over 1.1 billion ha would be suitable for growing wheat at an average maximum attainable yield level of 6.3 tonnes/ha, i.e. taking into account all climate, soil and terrain constraints. At the low technology level (subsistence farming), 1.5 billion ha would be suitable, but at an average maximum yield level of only 2.3 tonnes/ha. The suitable area at this lower input level is greater because, for example, tractors (high input level) cannot be used on steep slopes. For developing countries alone, the estimates are 314 million ha and 5.3 tonnes/ha under the high technology level because most of the suitable area for wheat at this input level is in the developed countries. For the other crops shown, the bulk of the suitable area is in the developing countries.

Summing over all crops and technology levels considered (see Box 4.1), it is estimated that about 30 percent of the world's land surface, or 4.2 billion ha, is suitable for rainfed agriculture (Table 4.6). Of this area, the developing countries have some .8 billion ha of land of varying qualities that have potential for growing rainfed crops at yields above an«acceptable» minimum level. Of this land, nearly 960 million ha are already in cultivation. The remaining 1.8 billion ha would therefore seem to provide significant scope for further expansion of agriculture in developing countries. However, this favourable impression must be much qualified if a number of considerations and constraints are taken into account.

First, the method of deriving the land suitability estimates: it is enough for a piece of land to support a single crop at a minimum yield level for it to be deemed suitable. For example, large tracts of land in North Africa permit cultivation of only olive trees. These lands therefore are counted as«suitable» although one might have little use for them in practice (see also Box 4.2 for further similar qualifications).

Second, the land balance (land with crop production potential not in agricultural use) is very unevenly distributed among regions and countries. Some 90 percent of the remaining 1.8 billion ha is in Latin America and sub-Saharan Africa, and more than half of the total is concentrated in just seven countries (Brazil, the Democratic Republic of the Congo, the Sudan, Angola, Argentina, Colombia and Bolivia). At the other extreme, there is virtually no spare land available for agricultural expansion in South Asia and the Near East/North Africa. In fact, in a few countries in these two latter regions, the land balance is negative, i.e. land classified as not suitable is made productive through human intervention such as terracing of sloping land, irrigation of arid and hyperarid land, etc. and is in agricultural use. Even within the relatively land-abundant regions, there is great diversity of land availability, in terms of both quantity and quality, among countries and subregions.

Third, much of the land also suffers from constraints such as ecological fragility, low fertility, toxicity, high incidence of disease or lack of infrastructure. These reduce its productivity, require high input use and management skills to permit its sustainable use, or require prohibitively high investments to be made accessible or disease-free. Alexandratos (1995, Table 4.2) shows that over 70 percent of the land with rainfed crop production potential in sub-Saharan Africa and Latin America suffers from one or more soil and terrain constraints. Natural causes as well as human intervention can also lead to deterioration of the productive potential of the resource, for example through soil erosion or salinization of irrigated areas. Hence this evaluation of suitability may contain elements of overestimation (see also Bot, Nachtergaele and Young, 2000) and much of the land balance cannot be considered to be a resource that is readily usable for food production on demand.

There is another cause for the land balance to be overestimated: it ignores land uses other than for growing the crops for which it was evaluated. Thus, forest cover, protected areas and land used for human settlements and economic infrastructure are not taken into account. Alexandratos (1995) estimated that forests cover at least 45 percent, protected areas some 12 percent and human settlements some 3 percent of the land balance, with wide regional differences. For example, in the land-scarce region of South Asia, some 45 percent of the land with crop production potential but not yet in agricultural use is estimated to be occupied by human settlements. This leaves little doubt that population growth and further urbanization will be a significant factor in reducing land availability for agricultural use in this region.

These considerations underline the need to interpret estimates of land balances with caution when assessing land availability for agricultural use. Cohen (1995) summarizes and evaluates all estimates made of available cultivable land, together with their underlying methods, and shows their extremely wide range. Young (1999) offers a critique of the more recent estimates of available cultivable land, including those given in Alexandratos (1995), and states that«an order-of-magnitude estimate reaches the conclusion that in a representative area with an estimated land balance of 50 percent, the realistic area is some 3 to 25 percent of the cultivable land».

4.3.2 Expansion of land in crop production

There is a widespread perception that there is no more, or very little, new land to bring under cultivation. Some of this perception may be well grounded in the specific situations of land-scarce countries and regions such as Japan, South Asia and the Near East/North Africa. Yet this perception may not apply, or may apply with much less force, to other parts of the world. As discussed above, there are large tracts of land with varying degrees of agricultural potential in several countries, most of them in sub-Saharan Africa and Latin America, with some in East Asia. However, this land may lack infrastructure, be partly under forest cover or be in wetlands that have to be protected for environmental reasons, or the people who would exploit it for agriculture lack access to appropriate technological packages or the economic incentives to adopt them.

In reality, expansion of land in agricultural use takes place all the time. It does so mainly in countries that combine growing needs for food and employment with limited access to technology packages that could increase intensification of cultivation on land already in agricultural use. The data show that expansion of arable land continues to be an important source of agricultural growth in sub-Saharan Africa, South America and East Asia, excluding China (Table 4.7).³

The projected expansion of arable land in crop production shown in Tables 4.7, 4.8 and 4.9, has been derived for the rainfed and irrigated land classes. In each country the following factors have been taken into account: (i) actual data or, in many cases, estimates for the base year 1997/99 on harvested land and yield by crop in each of the two classes; (ii) total arable land and cropping intensity in each class; (iii) production projections for each crop; (iv) likely increases in yield by crop and land class; (v) increases in the irrigated area; (vi) likely increases in cropping intensities; and (vii) the land balances for rainfed agriculture described in the preceding section, and for irrigated land discussed in the following section. This method was used only for the 93 developing countries covered in this study (see Appendix 1). For the developed countries or country groups, only projections of crop production have been made, which were then translated into projections for total harvested land and yield by crop.

The overall result for developing countries is a projected net increase in the arable area of 120 million ha (from 956 in the base year to 1076 in 2030), an increase of 12.6 percent (see Table 4.7).⁴ The increase for the period 1961/63 to 1997/99 was 172 million ha, an increase of 25 percent. Not surprisingly, the bulk of this projected expansion is expected to take place in sub-Saharan Africa (60 million), Latin America (41 million) and East Asia, excluding China (14 million), with almost no land expansion in the Near East/North Africa and South Asia regions and even a decline in the arable land area in China. The slowdown in the expansion of arable land is mainly a consequence of the projected slowdown in the growth of crop production and is common to all regions.

The projected increase of arable land in agricultural use is a small proportion (6.6 percent) of the total unused land with rainfed crop production potential. What does the empirical evidence show concerning the rate and process of land expansion for agricultural use in the developing countries? Microlevel analyses have generally established that under the socio-economic and institutional conditions (land tenure, etc.) prevailing in many developing countries, increases in output are obtained mainly through land expansion, where the physical potential for doing so exists. For example, in a careful analysis of the experience of Côte d'Ivoire, Lopez (1998) concludes that«the main response of annual crops to price incentives is to increase the area cultivated». Similar findings, such as the rate of deforestation being positively related to the price of maize, are reported for Mexico by Deininger and Minten (1999). Some of this land expansion is taking place at the expense of long rotation periods and fallows, a practice still common to many countries in sub-Saharan Africa, with the result that the natural fertility of the soil is reduced. Since fertilizer use is often uneconomic, the end result is soil mining and stagnation or outright reduction of yields.

The projected average annual increase in the developing countries' arable area of 3.75 million ha (120/32), compared with 4.8 million (172/36) in the historical period, is a net increase. It is the total of gross land expansion minus land taken out of production for various reasons, for example because of degradation or loss of economic viability. An unknown part of the new land to be brought into agriculture will come from land currently under forests. If all the additional land came from forested areas, this would imply an annual deforestation rate of 0.2 percent, compared with the 0.8 percent (or 15.4 million ha p.a.) for the 1980s and 0.6 percent (or 12.0 million ha p.a.) for the 1990s (FAO, 2001c). The latter estimates, of course, include deforestation from all causes, such as informal non-recorded agriculture, grazing, logging, gathering of fuelwood, etc.

The arable area in the world as a whole expanded between 1961/63 and 1997/99 by 155 million ha (or 11 percent), the result of two opposite trends: an increase of 172 million ha in the developing countries and a decline of 18 million ha in the developed ones. This decline in the arable area in the latter group has been accelerating over time (-0.3 percent p.a. in the industrial countries and -0.6 percent p.a. in transition countries during 1989-99). The longer-term forces determining such declines are sustained yield growth combined with a continuing slowdown in the growth of demand for their agricultural products. In addition, there are more temporary phenomena such as policy changes in the industrial countries and political and economic transition problems in the former centrally planned countries. No projections were made for arable land in the developed countries but, assuming a continuation of these trends, one would expect a further decline in the developed countries' arable area. However, this decline in arable area could in part be offset by the emerging trend towards a de-intensification of agriculture in these countries through increasing demand for organic products and for environmentally benign cultivation practices, and a possible minor shift of agriculture to temperate zones towards the end of the projection period because of climate change. The net effect of these countervailing forces could be a roughly constant or only marginally declining arable area in the developed countries. Arable area expansion for the world as a whole therefore would more or less equal that of the developing countries.

Although the developing countries' arable area is projected to expand by 120 million ha over the projection period, the harvested area will expand by 178 million ha or 20 percent, because of increases in cropping intensities (Table 4.8). The increase of harvested land over the historical period (1961/63 to 1997/99) was 221 million ha or 38 percent. Sub-Saharan Africa alone accounts for 63 million ha, or 35 percent, of the projected increase in harvested land, the highest among all regions. This is a consequence of the high and sustained growth in crop production projected for this region (see Table 4.1) combined with the region's scope for further land expansion. The other region for which a considerable expansion of the harvested area is foreseen, albeit at a slower pace than in the past, is Latin America with an increase of 45 million ha.

As mentioned before, the quality of the data for arable land use leaves much to be desired (see also Young, 1998). The data of harvested or sown areas for the major crops are more reliable. They show that expansion of harvested area continues to be an important source of agricultural growth, mainly in sub-Saharan Africa, but also in Southeast Asia and, to a lesser extent, in Latin America. Overall, for the developing countries, excluding China, the harvested area under the major crops (cereals, oilseeds, pulses, roots/tubers, cotton, sugar cane/ beet, rubber and tobacco) grew by 10 percent during the ten years from 1987/89 to 1997/99, or about 1 percent p.a. This is only slightly higher than the growth rate of 0.9 percent p.a. projected for all crops for the 21-year period 1988/90-2010 in Alexandratos, 1995 (p. 165).

The overall cropping intensity for developing countries will rise by about 6 percentage points over the projection period (from 93 to 99 percent). Cropping intensities continue to rise through shorter fallow periods and more multiple cropping. An increasing share of irrigated land in total agricultural land contributes to more multiple cropping. About one-third of the arable land in South and East Asia is irrigated, a share which is projected to rise to 40 percent in 2030. The high irrigation share is one of the reasons why the average cropping intensities in these regions are considerably higher than in the other regions. Average cropping intensities in developing countries, excluding China and India which together account for more than half of the irrigated area in the developing countries, are and will continue to be much lower.

The rise in cropping intensities has been one of the factors responsible for increasing the risk of land degradation and threatening sustainability, when it is not accompanied by technological change to conserve the land, including adequate and balanced use of fertilizers to compensate for soil nutrient removal by crops. It is expected that this risk will continue to exist because in many cases the socio-economic conditions will not favour the promotion of the technological changes required to ensure the sustainable intensification of land use (see Chapter 12 for a further discussion of this issue).

continued

¹ See Alexandratos (1995, p. 161, 168) for a discussion on problems with land use data.
² Unfortunately, revised data for harvested land and yields by crop for China (mainland) are not available until the results of the 1997 Chinese Agricultural Census have been processed and published. Therefore, ad hoc adjustments had to be made to base year data based on fragmentary non-official information on harvested land and yield by crop.
³ Historical data for China have been drastically revised upwards from 1985 onwards, which distorts the historical growth rates in Table 4.7 for East Asia (and for the total of developing countries).
⁴As mentioned in Section 4.2, data on arable land are unreliable for many countries. Therefore base year data were adjusted and are shown in column (4) as«1997/99 adjusted».