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Land and Environment : Agribusiness Assoc. of Australia
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Prospects for Feeding the World and for Rural Landscapes [1]

T. Fischer

 Australian Centre for International Research, GPO Box 1571, Canberra City, ACT 2601


Abstract

This paper discusses prospects for meeting world cereal demands up to the year 2020. Also considered are the issues of marginal lands, the persistence of large numbers of undernourished people, and some possible changes in rural landscapes. It is strongly informed by the various analyses of IFPRI on aspects of these issues. It is concluded that if research and development (R & D) investment is maintained in agriculture, crop yields can grow fast enough for the world to continue improving per capita food consumption without much increase in arable land used. Under-nourishment will however only decline rapidly if there is, in addition, more targeted investment in infrastructure and institutions to alleviate rural poverty. Increasing food production in the world's favourable arable lands can be sustainable and can relieve the pressure on the remaining forests, woodlands, uplands and dry marginal areas by making arable cropping there unattractive financially. Again targeted investments will be needed to facilitate the shift out of arable annual cropping to perennial cropping, land stewardship, and non-farm employment.

Introduction

Many have written recently on the subject of feeding the world, in particular Alexandratos, Evans, IFPRI, Cassman and Fresco, and I draw heavily on these sources. In the end however this is my view of what are the most important issues in this vast field. As I look at the food supply versus demand issue, I will concentrate on cereals, which comprise around 50 per cent of all food calories of mankind, not including their growing indirect contribution through feeding of grains such as maize and sorghum to food animals. Starting with the big picture, I then pass to the issues of land degradation, marginal lands and the uneven distribution of food. Finally I would like to speculate about the future structure of world agriculture, particularly rural landscapes. Much of my focus will be on developing countries, but developed countries cannot be ignored.

Global Food Security - The big picture

If we take, as did Cassman in his recent paper, real grain prices on the world market as a bell wether to reflect the balance between supply and demand, the world's grain consumers are doing well. Prices have been declining for over 100 years, and the last few decades or so have been no different, despite a few shocks in the 1970s and 1990s, and despite the dire predictions of Lester Brown and others. Grain availability per capita has increased in the last 30 years, and especially so in most developing countries. This has been the result of some crop area increase, often associated with cropping intensification due to irrigation, but mostly it is the consequence of yield increase. The latter in turn is the combination of improved varieties, more artificial fertiliser, and a greater proportion of crops being irrigated. It is impossible to be precise regarding the relative importance of these factors due to the positive interaction between all three. By way of illustration, the summary figures for progress since 1970 in developing Asia are impressive (see Table 1).

Table : Key statistics for population, food and income in developing Asia in 1970 and 1995; source Asian Development Bank (3)

Population million

Food Consumption Kcal/cap/d

Cereal production mt

Cereal area m ha

Cereal yield t/ha

Income $/cap/year

1970

1750

2045

313

235

1.32

177

1995

2793

2437

650

247

2.63

512

% change

+60

+24

+107

+4

+100

+189

FAO have made detailed projections of food production to 2010, but I will focus on projections to 2020 by IFPRI economists using their IMPACT model, which seeks prices that balance supply and demand according to appropriate elasticities. IFPRI suggests there will be continuing increased availability of cereals per capita, and further declines in real prices of grain, albeit at slower rates than in the past. Table 2 shows the aggregate quantities for cereal demand and supply. Noteworthy is the lower population (7.5 billion) than would have been projected only a few years ago; this is the median United Nations projection of 1998, which also puts peak world population at no more than 10 billion late in the century. Cereal demand increases 54 per cent in developing countries, comprising a 40 per cent increase in the food component, and a 100 per cent increase in the feed component to reach 445 million tonnes. Notwithstanding the large increase in their own production, there will be an almost doubling in developing country cereal imports. Nevertheless, they will still be growing 88 per cent of their cereal consumption. The former Soviet Union and Eastern Europe (both considered developed by IFPRI) will emerge as net exporters. The numbers also disguise an increase in exports from some Latin American nations to other developing countries. Finally developing country meat consumption will double, and net imports will increase 8-fold, but will still only amount to 3 per cent of consumption.

Table 2: Developing (dev'g) and developed (dev'd) country population, and demand for and supply of cereals in 1995 and as projected for 2020 by the IMPACT model (IFPRI 1999).

1995

2020

Dev'g

Dev'd

World

Dev'g

Dev'd

World

Population (million)

4495

1172

5666

6285

1217

7502

Demand (m t)

1071

706

1776

1652

814

2466

Supply: Area (m ha)

440

252

692

470

258

728

Yield (t/ha)

2.2

3.2

2.6

3.1

3.9

3.3

Production (m t)

965

812

1776

1460

1006

 2466

Net Imports (m t)

+106

-106

+192

-192

Details of the sources of cereal growth to the year 2020 are contained in Table 3. Note that these are exponential growth rates. Cereal crop area growth rate drops away to almost nothing in the developed world, and only manages 0.4 per cent per annum in the developing world. Yield growth becomes an even bigger fraction of future production growth, but at rates that are noticeably less than the last decade or so. Maize demand in developing countries will grow at a greater rate (2.4 per cent per annum) than wheat and rice (1.6 and 1.2 per cent per annum, respectively) because of the rapidly rising demand for animal products all over the developing world. Earlier IFPRI publications highlighted the high sensitivity of model outcomes on yield growth (and prices) to reduction in the investment in public agricultural research. Later, IFPRI emphasized the importance of investment in rural infrastructure and institutions, as well as research, if the yield projections are to be met.

Table 3 : Current production, and past and projected future rates (in bold) of cereal area and yield growth (%, p.a.) in developing (dev'g) and developed (dev'd) countries, calculated from IFPRI projections (19,20) and FAO statistics (11)

Cereals

Wheat

Rice

Maize

Dev'g

Dev'd

Dev'g

Dev'd

Dev'g

Dev'd

Dev'g

Dev'd

Production. 1998 (m t)

290

299

550

13

281

223

Area growth % p.a.

1966-1982

1.0

0.2

1.5

-0.1

0.6

3.7

1.7

0.7

1982-1998

0.4

-0.4

0.4

-1.2

0.2

-1.2

1.0

0.3

1995-2020

0.4

0.1

0.4

0

0.2

0.1

0.6

0.1

Yield Growth % p.a.

1996-1982

2.7

2.4

3.7

2.3

2.3

0.2

2.9

3.1

1982-1998

1.7

1.0

2.2

1.3

1.3

2.0

2.1

1.3

1995-2020

1.3

0.8

1.5

0.8

1.2

0.8

1.3

0.8

Evans has an excellent discussion of all plausible means of meeting these growing future food demands, including reductions in post harvest losses and in grain fed to animals. Most debate, however, centres around the projected yield increases of Table 3, something Cassman has considered in detail recently. He has closely watched maize yields in USA and rice yields at IRRI, sounding a note of caution. He points out that linear growth rates imply falling exponential rates, and that world maize yields are at 4.34 tonnes per hectare in 2000 according to the linear trend, the slope of which (60 kilograms per hectare per year) is only 1.4 per cent per annum, and close to that projected in Table 3 until the year 2020. He argues that breeding progress for yield in rice at IRRI has been slower than claimed.

In discussion of future yield growth, I think it is useful to look both at likely movements in (i) potential yield and (ii) closing the so-called yield gap, the difference between on farm economically attainable yield and actual yield. Attainable yield can be considered as potential yield discounted, typically by about 20 per cent, for economic and other on-farm considerations. It is also useful to separate irrigated and well watered situations, where potential yield determined by radiation and temperature prevail, from rain-fed and especially dry-land regions where yields are inevitably cut due to lack of water, defined as water-limited potential yield.

Increases in genetic yield potential through new cultivars tend to be reflected in similar relative increases at the farm level. Some farm yields are already approaching attainable ones in favoured regions (e.g., maize in Iowa, wheat in irrigated Yaqui Valley of Mexico and Indian Punjab, rice in central Luzon), meaning actual farm yield growth is limited by potential yield growth. Future projections for yield potential growth are therefore important. Little or no evidence was presented in a 1998 symposium on the subject that the growth rate in genetic yield potential of most crops is decreasing. In most crops, rates are around 0.5 to 1.0 per cent per annum, but from time to time there has been faster progress associated with breakthroughs, like semi-dwarf wheat and rice, and hybrid rice and maize. Overall the power seems still to reside with the breeding, not to mention the role of agronomy in realizing genetic potential in favoured and water-limited environments. But breeding for yield is taking more resources, including the growing need for even greater input from allied disciplines such as physiology and molecular biology.

In many places there remains substantial scope for closing the yield gap, with actual yields less than one half of attainable ones (e.g., most of sub Saharan Africa). In the developing world this requires applied and adaptive agricultural research, and agricultural extension, posing many challenges to crop agronomists (e.g., site specific nutrient management, conservation tillage, crop rotation, etc.). But there must also be attention to rural infrastructure, institutions, and agricultural policy. Lately there has been a lot of attention to innovative technology transfer paradigms, many of which contain reference to farmer participation and to action research. None of these activities are sufficient in themselves, but taken together yield gap closing should result.

In conclusion, and not wanting to down play the critical role of maintaining real investment in agricultural R & D, as emphasized by the IFPRI sensitivity analyses, and in rural infrastructure and institutions, I believe that a 1.3 per cent per annum growth rate in cereal yields out to 2020 is well within the capability of developing countries. A rate of 0.8 per cent per annum seems fine for developed countries, bearing in mind that some of the slow down in Table 3 in 1982-1998 has been due to the upheavals in the ex-USSR.

Land degradation, irrigation and the big picture

The world's vegetated land is 8,700 million hectares, comprising forest and woodland (4,000 million hectares), permanent pasture (3,200 hectares), and in 1997, arable crop land (,380 million hectares) and permanent crop land (trees and shrubs, 131 hectares). Scheer and Yadav cite a 1992 study pointing to 38 per cent of the world's arable crop land being degraded, having lost some or much productive capacity, principally due to water erosion, but nutrient loss and salinization are also important. The degradation of cropland is greatest in Africa (65 per cent) and Latin America (51 per cent). They also cite estimates that the productivity depressing effect of the increasing degradation of cropped land globally amounted to a yield loss of about 0.4 per cent per annum over the last 45 years. But this is mostly temporary degradation, and not loss of crop land area, such that the past yield gains referred to above in Table 3 are net of this loss, while likewise our forward projections may assume it will continue. Besides if it were slowed, or even reversed through more sustainable farming practices, then this would add to expected yield growth. Research points to many ways that the soil base of arable cropping could be improved.

More relevant to our discussion here is severe degradation, leading to permanent loss of cropland, essentially irreversible things like severe erosion, permanent salinization, exhaustion of non renewable water resources and loss of water to non-agricultural activities (to this we should also add cropland loss due to urbanization, but in Asia, where this is greatest, I estimate that it does not exceed 0.1 per cent per annum). How much loss of cropland is occurring is not clear. If severe degradation was running at 5 million hectares per annum, a high estimate, it would amount to 0.3 per cent per annum loss of crop land. Recent estimates for China and India, where talk of land losses due to degradation and urbanization is most common, do not show net loss of arable areas (FAO 1999).

It should also be pointed out that although potential new arable land of reasonable quality is scarce in the developed world and Asia, several hundred million hectares do exist in sub Saharan Africa and South America. There, net crop area increases in excess of the 0.4 per cent per annum referenced in Table 3 seem quite possible. Remoteness appears to be a major economic constraint on the development of this new land which is mostly tropical savanna; developed society may wish to impose other constraints, but it is unlikely the developing countries with favourable potential arable land would feel bound by this.

The percentage of cropland irrigated and the intensity of cropping (crop area per annum relative to cropland or arable land) are two other very important aspects of land management. In 1997, 268 million hectares, or approximately 19 per cent of all arable land, were irrigated, of which 218 million hectares were in developing countries, an area which included 48 per cent and 43 per cent of their wheat and rice areas, respectively, and a significantly greater proportion of the production. Indeed, about 57 per cent of developing country cereal production is irrigated (cf., only 23 per cent for developed countries). Irrigation expansion in developed countries appears to have almost ceased. For developing countries, Alexandratos estimated that irrigation area, after increasing at 2 per cent per annum between 1970 and 1990, would only increase at 0.8 per cent per annum from then until 2010, while cropping intensity on irrigated lands may also increase slightly, from 110 per cent in 1990 to 124 per cent. These intensity numbers exclude China, for which the national average in 1997 was claimed to be 154 per cent across all arable land, meaning that much of the land carries two crops per year. Development of new irrigation is becoming more expensive and water is becoming scarcer. There is clamour about a water crisis, but demand management and better agronomy to increase irrigation efficiency, which is presently very low in most developing countries, and water recycling in industry, could prevent increasing non-agricultural demands for water from reducing crop irrigation for some time to come. Overall then, expansion in irrigated cropping should continue to contribute to the yield growth, but not nearly to the extent seen in the last 30 years (see also Epilogue).

Marginal lands and the big picture

Favoured crop lands (irrigated and moderate to high rainfall areas) have undoubtedly shown remarkable yield progress in the last three decades. It is commonly stated that the remaining croplands, variously defined as less favoured or marginal or dryland, have largely missed out on progress. Marginal lands usually suffer from insufficient rainfall (some lands are considered marginal for other reasons, like irreversible soil problems of shallowness, excessive slope or high acidity, but lack of water is by far the main cause). I will use the definition of CIMMYT that a rainfed environment is marginal when the water-limited potential yield of a crop falls to less than 40 per cent of its potential yield. For example by this definition much of the Australian wheat belt, with an average ET of about 300mm compared to a potential one of around 500-600mm, is marginal. There is growing pressure for more focus on marginal croplands of developing countries. Partly this is because such areas are commonly perceived to have the greatest rural poverty and land degradation, while others see poorer progress to date, and hence greater scope for future progress through research. It is this last-mentioned issue that interests us here.

It is difficult to get a measure of the area and production of marginal croplands. Much of the wheat of North America, Australia and Eastern Russia is produced under marginal moisture conditions, but apart from this, most marginal cropland is in developing countries. CIMMYT estimates for the mid 80s indicate that 36 per cent of the area and 18 per cent of the production of developing country wheat is marginal. For rice, if marginal production is assumed to be all rice cropping which is not bunded and fully flooded through irrigation or high rainfall, and if we take the latter to be half of the rainfed lowland area and all the rainfed upland, we can estimate from IRRIs recent numbers that 32 per cent of area, but only 15 per cent of production, is marginal. For maize in the mid 90s, CIMMYT estimated 22 per cent of the non-temperate area of 65 million hectares, and 15 per cent of its production, is marginal (there are however also 31 million hectares of temperate maize in developing countries, and 43 million hectares in the rest of the world, most of which is definitely not marginal). Sorghum, millet, and barley are the marginal area cereals, and some 60 per cent of their area and 40 per cent of their production appears to come from marginal areas. However these crops only contributed 11 per cent of total developing world's cereal production in 1998.

Overall it would appear that no more than 20 per cent of world cereal production takes place in marginal lands, an amount relatively insignificant for the big picture. In addition, although there may be the impression that yield progress has been slower in such lands, especially in developing countries, there has been good progress in developed countries, as technologies spill over from more favoured areas and others are developed especially for dry areas. High yield potential wheat varieties are one example of spill over, while conservation tillage and chemical fallowing are examples of techniques targeting dry areas. The consequences are well illustrated by wheat yield change in Australia, a largely marginal production region . Wheat yield increase has averaged 1.0 per cent per annum since 1950, and over 2 per cent per annum in the last decade. Herbicides, more timely operations, improved varieties, reduced tillage techniques, and more recently, better crop rotations and greater use of nitrogen fertilizers are all implicated in this progress. Similar progress in wheat yields under dry conditions can be pointed to in developing countries like Turkey and Tunisia. In conclusion, although at first glance it might appear that marginal croplands are a major constraint on future yield progress needed to feed the world, progress can be made if research and extension is focussed on the problem. Besides even if it isn't made at the rate anticipated in Table 3, the relatively small contribution to global production from the marginal lands means that the pressure on good lands is not greatly increased.

Uneven distribution of food and need for targeted interventions

Many observers point with deep concern to the persistence of serious malnutrition in the world despite an apparently positive big picture of growing average per capita food production and a falling percentage of undernourished. According to IFPRI there are currently 800m people, largely in developing countries, who do not have access to sufficient food to lead healthy, productive lives. Some 160m of these are children, more than one in every four in developing countries. The majority of these people are in rural areas, many are subsistence farmers and the rural landless. Their numbers are not projected to decline rapidly, unless special attention is paid to both food access as well as food availability for the undernourished, the former meaning that they have the livelihood to acquire adequate amounts and quality of food. Studies in India have shown that investment in rural roads through its effect on non-farm rural employment has the biggest impact on rural poverty, followed by investment in agricultural research and development, and then investment in education, and finally in rural development. More recent work in China also supports investment in agricultural R and D, and in roads for greatest alleviation of poverty. These studies point out that many of these investment policies can be better targeted at the undernourished poor (e.g. land reform, market development for inputs and outputs, micro-credit, women's education, non-farm rural employment, research against micronutrient deficiencies, etc.). However targeting marginal areas referred to above may not necessarily be the most effective: at least one review of the situation failed to find a clear association between these and greater poverty. Still, wise targeting of substantial investments in the rural sector will be necessary if the absolute numbers of undernourished can be brought down to 300m by 2020, the goal of the recent World Food Summit.

It is an open question as to what extent mainstream agricultural research and development should be focussed on the twin problems of a