CHAPTER 2d (Continuation of Chapter 2) ~
~ PARAMETERS USEFUL FOR PERSPECTIVE AND CALCULATION ~
Edition 9 of March 2010 (Updated October 2010)
The top part of this Chapter 2 (Sections (2-A) through (2-D-h) is in another file - Chapter 2. (se2.html)
~ TABLE OF CONTENTS ~
(2-A) ~ Sizes of Small Things ~
(2-E) ~National Land-Use Information ~
(2-F) ~Climatic Data
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - se2dNOTE: The notation (su1) means that the data is used in the document analyzing the sustainability of the productivity of the world's food, fiber and water supply systems. (See elsewhere in this website.)
Part [Di] ~ Potential Cropland ~ [Di1]~Global, [Di2]~Regional Data,
The FAO says crop yields can grow through more intense crop production, more harvests per year - mainly made possible by more irrigation - and new technology in areas where land and water are scarce, such as farming with less plowing (03F1). Comments: The FAO says that there is little remaining potential for expansion of cropland area, and there seems to be a broad consensus on this -despite analyses (below) saying that arable land is about double the existing area of cropland.
Sub-Part [Di1] ~ Potential Cropland ~ Global ~
Globally, arable land per capita has been declining since 1948 (
In the entire world there are 15,749,300 km2 of arable land. [CIA] This is 11% of the world's total land area. The present world population (in 2010) is about 6.9 billion. Dividing the figure for population by that for arable land, we see that there are about 440 people per km2 of arable land. On a smaller scale that means about 4 people/ hectare. Only about a third of the world's 200-odd countries are actually within that realistic ratio of 4:1. In other words, we have already reached the limits of the number of people who can be supported by non-mechanized agriculture. (CIA World Factbook. Annual. US Government Printing Office.http://www.cia.gov/library/publications/the-world-factbook
Before 1960 the major contribution to increasing food supplies came from taking more land into cultivation. Since 1960 increasing crop yields (tonnes/ unit area) has been the predominant contributor to increasing food supplies (99Y1) (98E1). For the next 25-50 years, it is generally agreed that increasing crop yields must continue to be the predominant contributor to increasing food supplies. However all projections of future food productivity include an increase in cereal harvest area of 25,000 km2/ year and an increase it total cultivated area of 42,000 km2/ year (99Y1). All these projections are supported by estimates of arable land area capable of being cultivated but not yet cultivated that are sometimes as high as twice the area of croplands currently under cultivation, i.e. twice 15 million km2. Young (99Y1) has done much research that casts considerable doubts on notion that such a huge area lies idle, waiting for someone to come along with a plow. The fact that all of the numerous projections of future annual increases in cropland area are such a tiny fraction of the estimates of total arable, but unused, cropland provides tacit admission that Young is probably correct. Young also points out that the total area of cereal-producing croplands in the LDCs (less-developed countries) peaked in 1996 at 4.45 million km2 (out of a total area of arable land of 7.49 million km2) and by 2002 had fallen to 4.27 million km2. For the low-income food-deficient countries (LIFDCs) the total area of cereal-producing cropland peaked in 1998 at 3.45 million km2 (out of a total area of arable land of 5.4 million km2) and by 2002 had fallen to 3.29 million km2 (See www.land-resources.com). Five major studies analyzed by Young estimated that the amount of arable land in the developing world (excluding China) not being cultivated was 16.7 to 19.0 million km2 (about twice the presently cultivated area in the developing world [excluding China]).
Young personally visited 30 developing world countries to try to find the arable land not yet cultivated that studies keep estimating. Below are some of the contradictions that Young found (99Y1).
The above situations could hardly be the case if there were plenty of unused but sustainably cultivable arable land.
In the above nations the alleged large amounts of arable lands that are not being used as croplands are clearly totally inconsistent with the facts on the ground. It is quite apparent that estimates of arable land that are not being use as cropland are grossly in excess of what detailed measurements would find. Below are some possible sources of the error (99Y1).
Today, virtually all of the productive land on this planet is being exploited by agriculture. What remains unused is too steep, too wet, too dry or lacking in soil nutrients (89B8). (in se13.doc) (P. Buringh) (su1)
Global arable landper person declined from 0.32 ha. in 1961-1963 to 0.21 ha. in 1997-1999, and is expected to drop to 0.16 ha. by 2030. (Rosamund McDougall, "Desertification and migration: An Optimum Population Trust Briefing," Optimum Population Trust, November 2006.) Comments: All of this decrease is likely to be population-growth-related, since the total area of arable land appears to have remained fairly constant. It is growing slowly, but much semi-arid and arid land is being converted to cropland even though it is unlikely to be able to serve in this capacity sustainably due mainly to wind erosion.
Projections suggest that an added 1.2 million km2 of arable land will be required worldwide by 2030 (03N1). Comments: It is commonly believed that the bulk of increased production by 2030 will come from more intensive land use - not increased cropland area.
A good part of the 38,000 km2/ year net new cropland during 2003-2030 (to give 1.026 million km2 in 27 years) will probably come from forest conversion. A high proportion will have steep slopes and will be in zones with high rainfall, so the water erosion risk will be high unless suitable management techniques are adopted (00F2) (03N1).
The arable area in the world as a whole expanded between 1961 and 1963 and 1997 to 1999 by 1.55 million km2 (or 11%), the result of two opposite trends: an increase of 1.72 million km2 in developing countries and a decline of 0.18 million km2 in developed countries (03B3).
The projected average annual increase in developing countries' arable area of 37,500 km2 (120/32), compared with 48,000 km2 (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 (03B3).
Result for developing countries projects a net increase in arable area of 1.20 million km2 (from 9.56 in the base year to 10.76 km2 in 2030), an increase of 12.6% (Table 4.7) (4). The increase for 1961/ 1963 to 1997/ 1999 was 1.72 million km2, an increase of 25%. The bulk of this projected expansion is expected to take place in sub-Saharan Africa (0.60 million km2), Latin America (0.41 million km2) and East Asia, excluding China (0.14 million km2), 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 expansion of arable land is mainly a consequence of the projected slowdown in the growth of crop production, and is common to all regions. Comments: In Sub-Saharan Africa and South America, Slash/ burn agriculture could be a large part of the expansion, but this is highly non-sustainable, with fallow times being a small fraction of the time needed for the tropical soil to recover. Soybean production expansion in Brazil could also be a part of this data (03B3).
Table 4.7 ~ (Left Panel) Total arable land: past and projected (03B3) (la)
Table 4.7 ~ (Right Panel) Total arable land: past and projected (03B3)
Source: Column (1) - (3): FAOSTAT, November 2001.
Note: "World" includes a few countries not included in other country groups shown.
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) Comments: In Sub-Saharan Africa and South America, Slash/burn agriculture could be a large part of the expansion, but this is highly non-sustainable, with fallow times being a small fraction of the time needed for the tropical soil to recover (03B3).
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 (95A2), and states that "an order-of-magnitude estimate reaches the conclusion that in a representative area with an estimated land balance of 50%, the realistic area is 3-25% of cultivable land" (03B3).
There is another reason for the (crop) land balance to be over-estimated: it ignores land uses other than for growing the crops for which it was evaluated. Forest cover, protected areas and land used for human settlements and economic infrastructure are not taken into account. Alexandratos (95A2) estimated that forests cover at least 45%, protected areas 12% and human settlements 3% of the land balance, with wide regional differences. For example, in the land-scarce region of South Asia, 45% of the land with crop production potential, but not yet in agricultural use, is estimated to be occupied by human settlements. (03B3).
Much potential cropland 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 ((95A2), Table 4.2) shows that over 70% of the land with rain-fed crop production potential in sub-Saharan Africa and Latin America suffers from one or more soil- and terrain constraints (03B3).
Some 90% of the remaining 18 million km2 (of potential croplands) is in Latin America and sub-Saharan Africa. More than half of that total is concentrated in just 7 countries (Brazil, Democratic Republic of the Congo, 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 hyper-arid land, etc. and is in agricultural use (03B3).
Potential Croplands (All numbers in 10,000 km2) (76R1)
Col.2 = Net arable area in humid tropics
Col.3 = Arable land without irrigation outside humid tropics
Col.4 = Land where irrigation is required for even one crop
Col.5 = Gross cropped area without irrigation
Col.6 = Gross cropped area added by irrigation
Col.7 = Total potential gross cropped area (Col. 5+ Col. 6)
Revelle thus concludes that potential arable land capable of supporting crops without irrigation (Col.2+3) constitutes 22% of the world's ice-free land surface (vs. 10-11% now in use as croplands). Water is available to irrigate another 820,000 km2 (Col.4). Omitting arable land for which no water is available (about 2 million km2 world-wide) the ratio of potentially arable land to total land in Africa, Asia, and North America is typical of the world as a whole: about 1/5. In Australia, New Zealand, and USSR, the proportion is less: about 1/6-1/7. In Europe, however, more than 1/3 is arable, and in South America the proportion approaches 2 in 5. Where climatic conditions allow, more than one crop/ year can be grown. Col.5, 6, and 7 above indicate the potential: figures represent potential arable land multiplied by number of crops possible in a 4-month growing season.
Cultivated land/ capita, and potential for 2000 (76R1) (Obsolete data: of historical interest only) (Check the databases described in Chapter 11 for more recent data.)
Col. 2 = Cultivated area in 1970 - (million km2)
Col. 3 = Population in 1970- - - - (millions).
Col. 4 = Cultivated area/person in 1970 (ha.).
Col. 5 = Potential Gross Cropped Area (million km2) in 2000
- - -(See Col. 7 of the table above.)
Col. 6 = Projected population for the year 2000 (millions)
Col. 7 = Potential gross cropped area (ha/ person) in 2000
Of 13.60 million km2 under actual cultivation in 1970, only a tiny fraction yielded more than one crop/ year. The potential gross cropped area of 42.3 million km2 projected for 2000 represents a figure that could be achieved by growing more than one crop a year on roughly a third of 29 million net arable km2. Comments: Does Revelle consider land and irrigation water lost to urbanization in 2000? How about land lost to soil erosion and desertification? How about decreases in land productivity when land is cropped several times/ year for prolonged periods?
Estimated Cultivated land by region vs. Potentially Arable Land, 1965 ((78W1), p. 59, and (70T1), p. 33) (Obsolete data: of historical interest only) (Check the databases described in Chapter 11 for more recent data.)
Col.2 = Total ice-free land area (million km2).
Col.3 = Potentially arable area (million km2).
Col.4 = Presently cultivated area (million km2).
Col.5 = Col.4/ Col.3 (%).
Col.6 = Cultivated land/person (ha.).
Col.7 = Potentially arable land that is arid or semi-arid ((70T1), p. 33) (million km2).
NOTE: Col. 7 is broken down among 8 types of arid- and semi-arid lands in Ref. (70T1).
Table 7-7 of Ref. (78B3) gives total area, area of potential cropland, area of potential irrigable land, and the maximum grain productivity, by continent.
The global supply of arable land is estimated to be 15 million km2, most of which is now in production (80P2).
The area of potential land suitable for cultivation is 34 million km2 (26.3% of the ice-free land on Earth ((78B3), Buringh et al, 1975).
The Earth's cultivable area is 14.06 million km2, and the potential cultivable area is 31.9 million km2 (78B3). 4 million km2 can be irrigated; 2 million km2 are already irrigated (78B3). 40 million km2 of the earth are now grazed (30.4% of the world's ice-free land area) (78B3).
Ref. (80S1) cites Revelle's 1974 estimate that the total world area available for cropping (counting more than once, areas where multiple crops can be grown) is 41 million km2. Less than 50% of this potential area is now cropped (80S1).
Only 11% of the Earth's land surface is arable and naturally suited to crop production ((76P2), p. 149, Ref. 5).
Although the amount of potentially arable land is 40% more than is currently cultivated, according to UN FAO - an extra 20 million km2 - most of the uncultivated land is marginal, with poor soils and either too little rainfall or too much of it. Bringing it into production would require costly irrigation systems, or large-scale soil fertility enhancement measures. Without massive technological change or substantial investments, increases in food production will have to come from existing agricultural land (98H1). Comments: Current cropland inventory is 15 million km2, and 40% of that is 6 million km2 - not 20 million. Comments: Huge external debts in developing nations often make investments in irrigation impossible.
Under 50% of the world's land area is suitable for agriculture, including grazing; total arable (crop) land, in use and potential, is estimated to comprise about 30 million km2 (90L4). However, nearly all of the world's productive land, flat and with water, is already exploited. Most unexploited land is too steep, too wet, too dry, or too cold for agriculture (89B8).
The world's arable land could be expanded at most by 5 million km2 (94K3). However the productivity of this new land would be much below present levels in land now being cropped (94K3).
About 25% of current croplands should not be in production (82D2). Comments: Presumably this means too arid or steep etc. for sustainable cropping. More recent data would be worse.
An assessment of climate and soil conditions in 93 developing countries (excluding China) shows that an additional 21 million km2 could be cultivated (94B5). Comments: Apparently slope was not part of the assessment.
Of the 130 million km2 of ice-free land in the world, 26 million are not arable because the temperature is below freezing over 9 months of the year. In an added 19 million, there are fewer than three months of the year when available moisture from rain, snow, or water stored in the soil exceeds potential transpiration from plants and soil, and there are no practical sources of irrigation water. Climate alone, therefore limits potentially arable land to 85 million km2 (76R1). Comments: Also subtract urban ("developed") lands (See Chapter 6 and Section (3-C)) and excessively steep lands.
A 1967 President's Science Advisory Committee concluded, after an intense study, that 32 million km2 of the world's land can be cultivated (76R1), ((70T1), p.33). 26 million km2 are mountainous or arid where ground is rocky or covered with stony and shallow lithosols (76R1). Non-cultivable desert cover 17 million. Highly leached, arid, dominantly podzol soils in the forested regions of the cool temperate zone occupy 16 million (76R1). Another 7 million of sandy, undifferentiated soils ("regosols") are non-arable (76R1). Another 5 million of arctic tundra are too cold for crops (76R1). The Earth's 32 million km2 of arable land covers 24% of the ice-free land area of the earth - 2.3 times the currently cultivated land area (14.6 million km2), and over three times the area actually harvested in any given year. Of this total, 3 million km2 requires irrigation for even one crop (76R1). 7 million km2 of this potentially arable land is arid or semi-arid ((70T1), p. 33)
Developed countries have had no increases in cultivated land area over the past 20 years, but have had a 63% increase in yield/ unit-area. In the same period, developing countries have increased cultivated land area for grain production by 32%, and increased yield/ unit-area by 32% ((78B4), p.134).
Sub-Part [Di2] ~ Potential Croplands ~ Regional Data ~ [Di2a]~South America, [Di2b]~Far East, [Di2d]~Developing Nations, [Di2e]~Europe, [Di2f]~Southeast Asia, [Di2g]~Africa, [Di2h]~North America (Canada), [Di2i]~North America (British Columbia), [Di2j]~North America (US), [Di2k]~Central Asia ~ USSR,
[Di2a] ~ Potential Croplands ~ South America ~
Brazil's Trans-Amazon colonization scheme, announced in 1970, foresaw resettlement of 1 million families in the jungle by 1980. In 1978, only 7600 families had been resettled. In 1980 the plan was sharply curtailed (Ref. 66 of (96G2)).
Argentina, mostly from cropland expansion, increased wheat production by 68% in 1996 and maize production by 48% in 1997 and another 25% in 1998, following price rises in the immediately preceding years (03B4).
[Di2b] ~ Potential Croplands ~ Far East ~
Potential new cropland in China: 100,000 km2 (Ref. 18 of (96G2)). Comments: See the statement directly below.
During 1987-1992, 45% of land China converted to cropland in recent decades was restored to forest or grazing land after it was realized that these lands were of minimal value as croplands (96G2).
South Korea's additional potential cropland area is estimated at between 950 and 3320 km2. Its cultivated land in 1978 was 22,200 km2 (p. 89 of (81G2)).
[Di2d] ~ Potential Croplands ~ Developing Nations ~
The FAO estimates that 930,000 km2 are available for agricultural expansion in developing nations (excluding China) during 1990-2010 (mostly in sub-Saharan Africa and Latin America) (Ref. 69 of (96G2)).
[Di2e] ~ Potential Croplands ~ Europe ~
If Europe released for production, the 10% of its croplands set aside in 1996, and the US reopened 70,000 km2 of the least-sensitive land set aside under the CRP, 110,000 km2 would be added to global stock of cropland (enough for 150 million people ~ 20 months of global population growth) (Ref. 64 of (96G2)).
[Di2f] ~ Potential Croplands ~ Southeast Asia ~
Indonesia's problems with resettling 10 million families on 200,000 km2 of new land with poor soil and lack of water are described on pp. 38-39 of Ref. (96G2) and in its Ref. 67.
The Philippines area suited for cultivation = 98,000-116,000 km2 (Ref. 24 and 33 of (81G2)). (Some 70% of the 90,000 km2 now under cultivation is used for cereals (81G2).)
[Di2g] ~ Potential Croplands ~ Africa ~
The experience of Côte d'Ivoire, Lopez (98L1) concludes, is 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 (99D1). 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 reduction of yields (
[Di2h] ~ Potential Croplands ~ North America ~ Canada ~
Less than 9% of Canada's land area is capable of being cultivated, and, of that, only half is actually cropped. The other half of the 9% is used for pasture, forest, recreational lands, transportation corridors and urban- or industrial land (84S2). Almost 50% of Canada's land is totally unsuited for agricultural production because of the cold climate. A further 28% is so rocky or dry that there is virtually no potential for agriculture (84S2).
Canadian farmland left fallow (uncultivated) is expected to decline 3% in 1992 to 78,400 km2. This is the lowest in 52 years (92U1). Comments: Fallowing allows the land to regain moisture and fertility that was lost during cropping.
[Di2i] ~ Potential Croplands ~ North America ~ British Columbia (Canada) ~
Some 4% of land of British Columbia has soil and climate suitable for production of agricultural crops (84S2).
[Di2j] ~ Potential Croplands ~ North America ~ US ~
According to the SCS National Inventory of Soil and Water Conservation needs, 907,000 km2 are potentially arable (Classes I, II, III, IV) in the six Plains States, with 606,000 being cultivated. For the 8 mountain states: 279,000 km2 are potentially arable, with 172,000 being cultivated. For the Pacific Coast States 167,000 km2 are potentially arable, with 104,000 being cultivated (70T1).
Many of the 471,000 km2 of arable land in the Western US not now cultivated require new water supplies, extensive improvement, or special management practices for successful crop production (70T1).
About 90 million acres (364,000 km2) of US pasture land could be cropland (76P2).
The USDA says that 51 million acres (206,000 km2) of US pasture land (out of 134 million acres of pasture) have the potential to be croplands (82W2).
About 170,000 km2 of US forestland could be converted to prime farmland (82W1). Comments: Meaning that it is flat enough, mainly.
Under the Conservation Reserve Program (CRP), 150,000 km2 of marginal land (about equal to the expansion of the 1970s) were removed from US crop-production under 10-year contracts (96G2).
A 1988 USDA study estimates that 100,000 km2 of timberland in the US South have high or medium potential for conversion to cropland over the next 35 years (99N1).
[Di2k] ~ Potential Croplands ~ Central Asia ~ USSR (former) ~
The Virgin Lands program in 1954-1962 bought 300,000 km2 of grain-land into production. This land is now being returned to pasture, its previous use (Ref. 61 of (96G2)). Comments: Wind erosion (the main problem in converting arid lands to croplands) was the main cause.
Kazakhstan's grain-harvest area was 250,000 km2 in 1985; now it is 184,000 km2 (Ref. 61 of (96G2)). Comments: Much of this is due to the failures related to the Virgin Lands Program.
To to Top of this Review's Appendices (units, conversions, definitions)
SECTION (2-E) ~ National Land-Use Information ~ [Ea]~Asia, [Eb]~Africa, [Ec]~North America, [Ed]~South America and Central America, [Ee]~Europe and Australia,
See Chapter 11 Section (F) (Databases) "World Resources 2005" and other databases for large compilations of national and regional data on:
~ Total Land Area (2002)
~ Land Area Classifications ~ Forested
~ Land Area Classifications ~ Agriculture ~ Arable and Permanent Croplands (1992, 2002)
~ Land Area Classifications ~ Agriculture ~ Permanent Pasture (1992 and 2002)
~ Land Area Classifications ~ Drylands
~ Agricultural Land Area (2002)
~ Irrigated Cropland as a % of Total Land (2002)
~ Population Density (people/ sq. mile)
~ Areas protected as national parks, local parks, etc.
Part [Ea] ~ Land-Use Information ~ Asia ~ [Ea1]~General, [Ea2]~Central Asia, [Ea3]~Asian Sub-Continent, [EA4]~Far East, [Ea5]~Southeast Asia, [Ea6]~Middle East,
In terms of Major countries/ regions harvested area, global land area devoted to the main crops (cereals, roots and tubers, pulses, fibers, sugar crops and oil-crops) in the world as a whole expanded by 59 million ha (590,000 km2) (6%) since the mid-1970s. A 105-million ha increase in developing countries was accompanied by a 46-million ha decline in industrial countries and transition economies. The expansion of land under the four major oil-crops (soybeans, sunflower, rape and oil palm) was 630,000 km2. These four crops accounted for all the increase in world harvested area and more than compensated for the drastic declines in the area under cereals in industrial countries and transition economies (Table 3.19). In these countries, the expansion of oilseed area (250,000 km2) substituted and compensated for part of the deep decline in the area sown to cereals. But in developing countries, it seems likely that it was predominantly new land that came under cultivation, as land under the other crops also increased (03A1).
These numbers demonstrate the revolutionary changes in cropping patterns that occurred, particularly in developed countries, as a result of policies (e.g. EU support to oilseeds) and of changing demand patterns towards oils for food in developing countries and oilcakes/ meals for livestock feeding everywhere. They also demonstrate that cropland expansion still can play an important role in the growth of crop production. The 200% increase in oil-crop output between 1974/76 and 1997/99 in developing countries was brought about by a 70% (50 million ha) (500,000 km2) expansion of land under these crops. At the same time, land under their other crops also increased by an almost equal amount (Table 3.19) (03A1).
Sub-Part [Ea1] ~ Land-Use Information ~ Asia ~ General
In Asia, nearly 80% of potentially arable land is under cultivation (90U2), (90S8).
About 60% of cultivated, rain-fed land of the Middle East lies fallow each year. Areas of irrigated land left fallow each year range from nil in the UAR to 48-50% in Iraq and Sudan, and 40% in Afghanistan and Uran. Fallowing is practiced, in part to mitigate salinity in absence of adequate water supply (70T1).
A map of vegetation zones and oases of the Dry Belt of Inner Asia is given in Ref. (56V1) (pp. 288-9).
The 15 largest countries of southern and eastern Asia contain 25% of the world's cultivated land (as compared to 50% of the world's population and 14% of the world's inhabited land) (See Table in Chapter 2 of Ref. (80R1)).
A group at Wageningen Agricultural Univ. (Netherlands) estimates 75% of Southeast Asia's cultivable land is in use (80S1) (Earlier estimate: 93%).
Sub-Part [Ea2] ~ Land-Use Information ~ Asia ~
Central Asia ~
The Russian Federation has 2.32 million km2 of agricultural land (96G2).
[Ea2a] ~Land-Use Information ~ Asia ~ Central Asia ~ Russia ~
About two third of total agricultural phytomass of Russia are concentrated in the zones of steppe and temperate forests (Table 3). The distribution of the average phytomass density is geographically dependent, i.e. from 0.89 kg/ m2 in northern tundra to 1.04 kg/ m2 in southern steppe and 1.00 kg/ m2 in semi-desert- and desert zones (03S2).
Table 1. Phytomass of Russia's Agricultural Land (1990) (03S2)
Agricultural Land|Cropland|Hay land|Perennials|Total
Area, 106 ha~ ~ ~ | 130.34 | 78.96~ | ~2.56~ ~ |211.86
Phytomass, Tg. C | 397.4~ | 141.2~ | ~3.6 ~ ~ |542.1
Density, kg/m2 ~ | ~ 0.0~ | ~ 0.0~ | 24.8 ~ ~ | 24.8
Green part ~ ~ ~ | 397.4~ | 141.2~ | 28.3 ~ ~ |566.9
Woody part ~ ~ ~ | 251.1~ | 159.2~ | ~7.0 ~ ~ |417.2
Above ground ~ ~ | 648.5~ | 302.1~ | 37.9 ~ ~ |988.5
Below ground ~ ~ | 0.498~ | ~0.380 | 1.378~ ~ |0.464
1 Tg. = 1 billion tonnes = 1 Gt.
Table 2. Net Primary Production of Russia's Agricultural Land (1990) (03S2)
1 Tg. = 1 billion tonnes = 1 Gt.
Russia has managed (agricultural) land covering 2.12 million km2 (Land of Russia, 1995), including 1.30 million km2 of cropland. The rest (0.80 million km2) falls into the category of so-called other agricultural land - hay land (03S2). (la)
In spite of the huge extent of Russia total agricultural area occupies about 12% of the territory. This fact indicates rather limited natural potential of the country for agriculture that is caused by cold and humid climate, unsuitable for cropping mountain relief and expansion of poorly drained plains. The geographical variety stipulates production of different crops from which cereals, grasses and perennials are prevailed. These crops occupied more than 75% of the sown area of Russia in 1990 (03S2).
The arable area for all agricultural crops in Russia exceeded 1.0 million km2 in 1996. The structure of the arable area was as follows: perennial herbs (about 19.4% of the total), spring wheat (16.4%), spring barley (11.4%), winter wheat (9.4%), annual herbs (8.2%), oats (6.9%), corn for silage, green fodder and silage (6.4%), winter rye (4.2%), sunflower (3.9%), potatoes (3.4%), cereal-leguminous and buckwheat (1.4% each), millet (1.2%), sugar-beet (1.1%). Fruit/berry plants, vegetables, vineyards, corn for grain, soybean, winter barley, fodder roots, rice, and flax-fiber occupied less than 1% of sown area (each). Besides, at state farms, cereals (53.6% of total areas) and fodder crops (36%) prevailed; in crops of farming, cereals took precedence (more than 70% of their total sown area); and in crops of population, potatoes and vegetables prevailed (80%) (03S1).
As of 1/01/01, 1.291 million km2 or 7.6% of the total Russian land area was under the private ownership of citizens and legal entities. Of this land, 7.2%, or 1.22.6 million km2, belongs to citizens and their unions; 0.065 million km2 or 0.4% belongs to legal entities. The area of land portioned out among former members of state and collective farms was 6.6% (1.134 million km2) of the total Russian land area, or 87.8% of land in private ownership (03L1).
As of 1/1/01, Russia's farmland area by all categories was 2.211 million km2 or 12.9% of the total land area of the country. Non-agricultural lands account for 14.88 million km2 or 87.1%. The share of arable lands in the farmland area was 56.3%; the share of fallow lands was 1.8%. Gardens and orchards accounted for 0.8%; hayfields, for 10.7%, and pastures, for 30.4%. 71.3% of farmland was used by agricultural enterprises. Citizens used 18.7% of total farmland area (03L1).
The land area of the Russian Federation is 17.1 million km2. The breakdown is: agricultural lands, 4.06 million km2 (23.8% of the total land area of Russia); settlement lands, 0.187 (1.1%), including lands within the precincts of urban settlements (0.078), and in the precincts of rural settlements (0.109); lands of industry, transport, communication, and others, 0.173 (1.0%); specially protected lands, 0.32 (1.9%); forest lands, 10.97 km2 (64.1%); lands under water, 27.8 km2 (1.6%); and reserve lands, 1.112 million km2 (6.5% of Russia's total land area) (03L1).
Improvement in Russia's agricultural lands was sought by irrigating 14 km2, draining 24 km2, restoring 157 km2 of the improved lands, and ameliorating 392 km2. In addition, 210 km2 of forest shelterbelts were planted (03Z1).
In 1998, the structure of Russia's arable area (916,000 km2) was: grain-crops, 50,8000 km2; industrial crops, 64,000 km2; potatoes, vegetables, and gourds, 41,000 km2; and forage crops, 300,000 km2 (03Z1). Gross harvesting of grain crops made up more than 88 million tons (t). In addition, Russia's farms harvested more than 37 million t of potatoes, more than 11 million t of vegetables, about 14 million tonnes of sugar beet, and about 2.7 million tonnes of fruits and berries. More than 90% of potatoes, more than 70% of vegetables, and about 80% of fruits and berries were produced in the private sector (03Z1).
Agricultural enterprises in Russia use more than 208 million hectares (ha) of agricultural lands, including more than 125 million ha of arable lands, 19 million ha of hayfields, and 60 million ha of pastures (03Z1).
[Ea2b] ~ Land-Use Information ~ Central Asia ~ Azerbaijan ~
(87,000 km2). Over 12,100 km2 of Azerbaijan are used to grow crops. Chief agricultural district; Kura River Valley. Population: 7 million (94K1).
[Ea2c] ~ Land-Use Information ~ Central Asia ~ Kazakhstan ~
(2.75 million km2 total area): 1.97 million km2 are used for agriculture. Some 99.7% of Kazakhstan land characterized as arable, and 78% of all other land, are used in agriculture (93M2). Some 18% is used for crops, the rest is grazing land. 233,000 km2 are used for grain (93M2). Non-irrigated cropland area is 336,493 km2; Irrigated cropland: 18,560 km2. Perennial grasses: 779 km2; Hay: 46,249 km2: Pasture: 1,573,560 km2, Total: 1,971,171 km2 (93M2).
The Institute for Soil Management estimates that Kazakhstan's grain land area will be reduced by over 25% when the rapidly eroding portion of its grain land is abandoned (97B2). Grain land in Kazakstan is forecasted to stabilize at 130-160,000 km2 - 50-67% of the 1980s peak area (97G1).
[Ea2d] ~ Land-Use Information ~ Central Asia ~ Mongolia ~
Land use patterns in Mongolia, Inner Mongolia (in China), Xinjiang (in China), and Tuva, Buryatia and Chita Oblast (in Russia) are shown on a map in Ref. (
[Ea2e] ~ Land-Use Information ~ Central Asia ~ Soviet Union (former) ~
Around 1970, the Soviets consistently fallowed 170-180,000 km2 in the dryland region, but after 1972, fallow remained at 110-120,000 km2 ((78B2), p. 29).
Some 27% of the former Soviet Union's land area is "agricultural." No more than 2/3 of this land is arable (89S3). In 1987, Soviet farmers cultivated 2.26 million km2 (89S3). Harvested grain-area: 1.23 million km2 in 1977; 0.94 million km2 in 1994 (95B1).
USSR summer fallow: 170-180,000 km2 (late 1960s-early 1970s) (84B2). (la)
USSR summer fallow: 120,000 km2 (mid-1970s) (84B2). (la)
Peak Soviet Union grain area of 1.23 million km2 (1979) shrank to 910,000 km2 in 1995 as falling productivity forced abandonment of marginal, often heavily eroded, land (Ref. 17 of (97B2)).
Agricultural land increased by 1.38%/ year during 1986-1996 in West Asia (00F1).
Sub-Part [Ea3] ~ Land-Use Information ~ Asian Sub-Continent ~
Land use in India in millions of km2 (and %) (OECD data is from 1987 - historical value only.)
Permanent pastures + other grasslands
0.12 ( 3.7%)
Land under cultivable tree crops
0.04 ( 1.3%)
Other non-agricultural uses
Barren and wasteland
No records (including urban)
0.24 ( 7.3%)
[Ea3a] ~ Land-Use Information ~ Asian Sub-Continent ~ Bangladesh ~
Bangladesh's cultivable area: 94,000 km2. Net cropped area (1977-1978): 84,000 km2 (81G2).
[Ea3b] ~ Land-Use Information ~ Asian Sub-Continent ~ India ~
More than 90% of the terrain in the Indian state of Uttaranchal is classified as hilly and two thirds (of that) is in forests. This limits the availability of land for agriculture (05U1). Comments: Urban lands also tend to be located on fairly level land, so only a fraction of the 10% level land can be used for agriculture.
About 70% of India's land is unsuitable for cultivation because of dryness of climate, steepness of slope, and outcroppings of rock or laterite. India has an actual cultivated area of 930,000 km2 (30% of its total area) and 360 people/ cultivated km2 ((56G1), p. 338).
Some useful discussions/ information on Indian agriculture are found in Ref. (70K1).
In the Jawaja Block in Ajmer District in Rajasthan India in a broad pass through Aravalli Hills are 100,000 people on 585 km2 (245 cropped, 240 barren and uncultivable, 24 non-agricultural, 73 owned by Forestry Department) (90S6).
India plus Pakistan contain 1.7 million km2 of arid land (86G2). (la)
While 20% of the arid land in India's Rajasthan could be cultivated in the 1970s, 30% was being cultivated in 1951, and 60% was being cultivated in 1971, mainly at the expense of grazing lands and traditional long-fallow periods (FAO data) (86G2) (86G3) (FAO data).
South Asia's agricultural land area has remained constant for over 20 years (2.23 million km2) (00F1).
[Ea3c] ~ Land-Use Information ~ Asian Sub-Continent ~ Nepal ~
Cultivated area on Nepal's hill-slopes increased from 8,000 km2 to 15,000 km2 from 1970-71 to 1985-86. Over the same period, forest area declined from 64,000 to 43,000 km2 (91N2).
Sub-Part [Ea4] ~ Land-Use Information ~ Far East
China has about 960,000 km2 of arable land, but it may be as high as 1.25 million km2 (99B1).
Far East: Multiple-Cropping (95B2)
Taiwan~ | 1.90 in 1964| 1.55 in 1980| 1.23 in 1993
Japan ~ | 1.33 in 1960| 1.03 in 1980| 1.03 in 1988
S. Korea| 1.45 in 1963| 1.30 in 1980| 1.08 in 1992
(A figure like 1.45 means 45% of croplands were cropped twice, etc.).
(South Korea peaked in 1963).
(Downward trend is attributed partly to rising prosperity (labor shortages).)
Conversion of grain land to other uses, combined with a decline in multiple cropping over the past few decades, cost Japan 52% of its grain-harvest area, South Korea 46%, and Taiwan 42%. As a result, by 1994, these 3 countries collectively imported 71% of their grain (95B2).
[Ea4a] ~ Land-Use Information ~ Far East ~ China ~
China's shortage of farmland is expected to exceed 66,700 km2 by 2020, according to a senior official with the Ministry of Agriculture. Official statistics show that China has 1.22 million km2 of farmland, accounting for less than 7% of the world total. Of the total, only 1.04 million km2 - 1.0667 million km2 is used for grain production. An average of nearly 10,000 km2 was lost each year between 1996 and 2004, but the loss dropped to 3600 km2 in 2005 thanks to tough measures imposed by the government. China's territory is 9.6 million km2. More than 60% of the total population lives on the plains and basins that make up less than 33% of China's territory. One third of China's area is mountainous, about 25% of China is plateau, and about 10% is hilly (
China's per-capita area of cultivated land is about 40% of the world's average level("Look on Green GDP Objectively", China Economic Net (6/30/04).). Comments: This perhaps explains why China has so much irrigated cropland.
China's arable land dropped by 2% in 2003, putting pressure on China's ability to feed its population. It fed 20% of the world's population on 7% of the world's arable land for the 1990s, now has 1.234 million km2 of available farmland. China's per-capita arable land dropped from 0.098 ha. in 2002 to 0.095 ha. in 2003. China, with 1.3 billion people, has seen falling grain output, with production plunging from 512 million tons in 1998 to 430 million tons in 2003. [Comments: Part of this might be due to soybean area growth.]~China's growing demands on world markets have caused food prices to rise domestically and globally. The loss of arable land has been the result of development and urbanization in rural areas, as well as desertification and projects like the Three Gorges Dam. From 1998 to 2002, Chinese croplands were reduced by 99,000 km2, due to requisitioning of land by local governments. The central government has ended unauthorized requisitioning of farmlands("China's Arable Land Shrank 2% in 2003, Hurting Grain Output", Agence France Presse (4/9/04)).
China's per-capita farmland area was 0.097 ha. around 2002 ("China Marks 34th Earth Day with Focus on Resources Protection", Xinhua General News Service (4/22/03)).
Rapid economic development in China saw farmland acreage drop to 1.22 million km2 in 2005, 3616 km2 less than in 2004. China's per-capita arable land was 0.093 hectares in October, 2005, down from 0.094 hectares in October, 2004, according to a China Youth Daily report. A recent national land survey (excluding Hong Kong, Macao and Taiwan) by China's Ministry of Land and Resources showed that land used for new construction (urbanization) totaled 2120 km2 in 2005. During the 10th Five-Year Plan (2001-2005) period, China lost 61,600 km2 of arable land, an average of 12,300 km2/ year annually, as a result of economic growth and frequent adjustments to the agricultural production structure. Accelerated industrialization and urbanization, expanding investment and afforestation also contributed to the decrease. Vice Minister of Agriculture pointed out that China could have problems feeding its 1.3 billion-plus population unless the trend is curbed. "With the current acreage, it would be difficult to guarantee China's safe grain supply," he said. A ministry official said that the 11th Five-Year Development Guidelines (2006-2010) call for the cultivation of a guaranteed 1.20 million km2 of arable land. This means that China can only afford to lose 20,000 km2 of farmland over the next 5 years. In 2005 China tightened restrictions on the acquisition of farmland for construction. China's annual grain production is 484 million tons. (Xinhua News Agency (April 6/06))
The US has 8 times as much land useable for agriculture as China, even though China and the US are of similar size (74H1). Hilly and mountainous soil constitutes 65% of China's land. Government policy prohibits cultivation on slopes steeper than 28%. 15% of China's commune land are allowed to be used by individuals to produce crops for sale or for home consumption. North and west China have extensive grasslands that are too dry or cold for intensive cultivation (82B2).
Agricultural land (cropland + grazing land) increased 0.8%/ year during 1986-1996 in China (00F1).
Some 16% of China's land is desert (6/29/99 Xinhua). (la) (0.16 x 9.597 million km2 = 1.54 million km2 See table below.)
Land Use in China ~ Areas in millions of km2 (%) (Ref. 2 of (82B2)) (la)
China'sfood-growing capacity is mainly in a band of river valleys along China's southern and eastern coasts (about 1/3 of China) (See map in Ref. (94B3)). 51% (9.3 million km2) of China is steep uplands (watershed slopes over 30 degrees) (94W3).
China's arable land/ capita shrank by more than 50% in the past 40 years (95K2).
China's grain-growing area declined 9% since 1976 due to urbanization and to the shift to more profitable crops (Ref. 34 of (88B4)) e.g. soybeans. China's grain-producing area: 908,000 km2 in 1990; 874,000 km2 in 1994 (1% drop/ year) (94B3).
Per-capita Area Planted to Grain in China (89L1)
(1990 data is extrapolated.) Comments: This data needs to be adjusted to account, in some way, for soybean area expansion.
Grain-land area in China: 908,000 km2 in 1990; 857,000 in 1994 (95B2), (Some 80% of China's grain harvest is from irrigated land.)
Vegetable Area vs. Time (95B2) (1000 km2)
Comments: Does "vegetable" include soybeans?
China is slightly larger than US. About 11% of China cultivated vs. 17.5% in the US (81H2).
Some 4 million km2 (42% of 9.6 million km2 total) of China were originally grasslands. More than half of these grasslands are in northern China (92N2).
China's land area suitable for agriculture dropped from 1,120,000 km2 in 1957 to 1,040,000 km2 in 1965, to 960,000 km2 in 1990. China's per-capita arable area has fallen 50% since 1957 (96M1). Comments: Much of this 160,000 km2 drop over 33 years could easily be due to urbanization.
China's loess (wind-deposited soil with low organic matter content) plateau covers 500,000 km2 (92D1). (la)
China's Loess plateau covers 500,000 km2 of which 110,000 km2 produce about 80% of sediment (81H2).
Total area of China's Loess Plateau (360,000 km2). Thickness of loess: 30-200+ m. Organic matter: 20,000 tonnes/ km2. Loess has covered 633,000 km2 of China (89Y2). No water is available for irrigation on China's Loess Plateau (89Y2).
China's deserts are widely distributed throughout the northern districts, and cover 13% of China's total land area of 9.6 million km2 (86W2). Comments: China's deserts are expanding rapidly, so this data is obsolete.
[Ea4b] ~ Land-Use Information ~ Far East ~ Japan ~
Some 67% of Japan is forested and under strict state control. Less than 20% of Japan is cultivated, but that is cultivated intensely (largely to grow surplus, government-subsidized crops of rice!) ((74C1), p. 219).
Japan's Grain-land area (plotted on p. 91 of (95B2)) (Areas are in units of 1000 km2)
Area | 50 | 50 | 33 | 27 | 25
Sub-Part [Ea5] ~ Land-Use Information ~ Southeast Asia ~
Thailand has 9.82 million hectares (98,200 km2) of rice fields (08U1).
The Philippines 4.0 million hectares (40,000 km2) of rice fields are spread over 7,000 (square) miles (08U1).
In the Philippines, hillside agriculture accounted for 10% of all agricultural lands in 1960, but 30% in 1987 (Per Pinstrup Anderson and Rajul Pandya-Lorch, "Alleviating Poverty, Intensifying Agriculture and Effectively Managing Natural Resources", Food, Agriculture and the Environment Discussion Paper 1, International Food Policy Research Institute, Washington DC (1994).) Comments: Presumably "agricultural" here refers only to croplands, not grazing lands.
[Ea5a] ~ Land-Use Information ~ Southeast Asia ~ Java ~
Java has one of the most densely populated islands in the world. 136,000 km2 with 160 million in 1984 give 787 people/ km2. A central range of volcanoes in Java limits level land for cultivation (90H2). Slopes over 50% are being cultivated on a continuous basis in Java (90H2).
[Ea5b] ~ Land-Use Information ~ Southeast Asia ~ Malaysia ~
Hill-slopes in Malaysia comprise about 80% of land area (91H4). In Malaysia's Cameron Highlands most cultivated areas are on slopes of 18-70% (91H4). Malaysia has severe soil erosion even though terracing is common (91H4).
[Ea5c] ~ Land-Use Information ~ Southeast Asia ~ Philippines ~
Over 58% of Philippine land has slopes over 11% (Ref. 1 of (95P1)).(la) Cultivated upland forest area increased from under 10% of total cultivated area in 1960 to over 30% in 1987. Cropped area in lowlands increased 1.9% during 1980-1987; hillside-cropped area expanded 7.6% (Ref. 49 of (96G2)). Cultivated upland forest (Ref. 35 of (97G1)): 10% of total cultivated area in 1960 (30+% in 1987).
[Ea5d] ~ Land-Use Information ~ Southeast Asia ~ Thailand ~
Thailand's 514,000 km2 (total land area) includes 200,000 cultivated km2, of which 140,000 are cropped annually (p. 63 of (81G2)).
Cultivation of rice alone on unsuitable soils in Thailand occurs on 22,000 km2; upland crops on unsuitable soils accounts for an added 23,000 km2 (88P3).
Sub-Part [Ea6] ~ Land-Use Information ~ Middle East ~
Some characteristics of land degradation in the Arab States region - results of a worldwide assessment of soil degradation problems, the GLASOD project, (ISRIC, 1991). (la)
C.2 Total degraded land (% of total land)
C.3 lightly degraded land (% of total land) (C.3+ C.4+ C.5 = C.2)
C.4 moderately degraded land (% of total land)
C.5 strongly degraded land (% of total land)
C.6 % of degradation by water erosion (C.6+ C.7+ C.8+ C.9= 100%)
C.7 % of degradation by wind erosion
C.8 % of degradation by chemical degradation
C.9 % of degradation by physical degradation
C.10 % of degradation caused by deforestation (C.10+ C.11+ C.12= 100%)
C.11 % of degradation caused by overgrazing
C.12 % of degradation caused by agricultural activities
Col.1 Population size, 1995 (millions)
Col.2 Population growth rate (1990-95) (%/ year)
Col.3 Percentage urban (1995)
Col.4 Urban pop. growth rate (1990-95) (%/ year)
Col.5 Cropland (1993) (ha/ capita)
Col.6 Forest/ woodland (1993) (ha/ capita)
Col.7 Renewable water (1995) (m3/ capita/ day)
Some demographic characteristics and natural resources availability in the Arab States region(96M3) (Data sources are:
[Ea6a] ~ Land-Use Information ~ Middle-East ~ Lebanon ~ (10,400 km2 total area)
Terraced lands in Lebanon cover 950 km2. Nearly all exhibits clear signs of terrace degradation and decay (94Z1). (la)
[Ea6b] ~Land-Use Information ~ Middle-East ~ Saudi Arabia ~
About 30,000 km2 were under cultivation in 1988, vs. 1500 km2 in 1975. Saudi farmers now produce 35% of Saudi Arabia's food, vs. 15% in 1984 ((90W1), p. 176).
Go to Top of this Review's Appendices (units, conversions, definitions)
Part [Eb] ~ Land-Use Information ~ Africa ~ [Eb1]~General, [Eb2]~North Africa, [Eb3]~Eastern Africa, [Eb4]~Central Africa, [Eb5]~West Africa, [Eb6]~Southern Africa
Sub-Part [Eb1] ~ Land-Use Information ~ Africa ~ General
Before the 1950s, African farmers routinely would leave less productive fields fallow for a generation. Then the population exploded and now every piece of land is taken up (statement by USDA soil scientist Hari Eswaran) (
Arable land per-capita declined 24.5% in Africa between 1980-93, vs. global average of 18% (10/15/99 ENN Direct).
Africa's land area = 29.7 million km2 (87L1). In early 1980s, 1.81 million were cultivated, 7.84 million were permanent pasture, 6.96 million were forest. The remaining 13.09 million were shrubs, desert, and miscellaneous uses. Population of Africa: 380 million (87L1). (la)
About 30% (22,245 km2) of Sub-Saharan Africa can sustain production of rain-fed crops. 1/4 of that is used for crops. Cropland acreage in Sub-Saharan Africa expanded 0.7%/ year over the past 20 years ((90W1), p. 89).
As of 1993, there were 663 public reserves or parks in Sub-Saharan Africa, totaling 1.252 million km2, no more than 4.6% of the total land area of the region, compared to 6% for the world as a whole (95M1). Comments: The figure for the world as a whole is now (2003) closer to 10%.
Some 19% of Africa's soils are inherently fertile, as compared to 36% in Asia (87H1). Most of Africa's arable soils are coarse; clay content is so low that soils cannot hold moisture, and are therefore highly susceptible to erosion ((90W1), p. 90, Ref. 21).
About 50,000 km2 are irrigated in Africa (mainly in Madagascar, Nigeria and Sudan). Some 200,000 km2 may be suitable for irrigation - most of it in the 3 above nations plus Chad, Ethiopia, Malawi, Mali, Mauritania, Senegal and Uganda (Ref. 24 of (90W1), p. 90). Comments: Huge external debts tend to prevent investments in irrigation. The world's second-fastest population growth rate absorbs whatever financial capital is produced internally.
About 1 million km2 of new land have been bought into cultivation in Africa over the 7 decades prior to 1988. Most of this land was rendered unproductive and barren shortly after vegetation was removed (88L1).
Moisture Zones in Africa (million km2) (93H1) (Data from M. Hulme, R. Marsh, P. D. Jones, Climate Research, 2 (1992) pp.1-22) (la)
Sub-Part [Eb2] ~ Land-Use Information ~ North Africa ~
Sub-Part [Eb3] ~ Land-Use Information ~ Eastern Africa (Ethiopia, Kenya, Somalia, Sudan, Tanzania) (Note: Eritrea is now part of Ethiopia. It bordered on the Red Sea.) ~
Tanzanian farmers cultivate 63,000 km2 of Tanzania's 430,000 km2 of arable land (04K2).
[Eb3a] ~ Land-Use Information ~ Eastern Africa ~ Kenya (total land area = 580,370 km2 ) ~
Population densities for areas with large proportions of arable land, such as Western, Central and Nyanza provinces in Kenya, have reached over 230/ km2 (
Only 17.5% of Kenya's land is suitable for cultivation (01U4).
Population in Kenya's Machakos District is 1.1 million, but carrying capacity for subsistence farming = 530,000. Machakos District of Kenya has 14,156 km2, of which 10,000 is in mixed farming. Average farm size: (2 ha crops+ 3 ha grazing) (3 adults+ 6 children) (90K1).
Only 17.5% of Kenya's land is suitable for cultivation (01U1). Population densities in Kenya for areas with large proportions of arable land, such as Western, Central and Nyanza Provinces: over 230 persons/ km2 (01U1).
Cultivated area: 91,238 km2 (17.2% of Kenya). All land suitable for rain-fed cropping is cultivated (91D2).
In 1946 there were 5 million Kenyans. Now there are 30 million (98M1).
About 20% of Kenya receives enough rainfall to raise cash crops (98M1).
In the last 20 years, tens of thousands of people have migrated into Kenyan lands not suitable for farming. These farmers have plowed under and over-grazed buffer zones around parks and reserves that wild animals must use as dispersal areas during wet seasons. Kenyan wild lands are disappearing at 2%/ year (98M1).
In Kenya's Taita Hills, a range of mountains sandwiched between the western and eastern halves of Tsavo Park, competition for land over the last 25 years has forced tens of thousands of Taita people to migrate from the fertile slopes of the mountains to rangelands below, an arid savannah that was carved up into large communal ranches for cattle grazing in the 1960s (98M1).
Sub-Part [Eb4] ~ Land-Use Information ~ Central Africa (Burundi, Central African Republic, Congo (Belgian Congo, Zaire), Gabon, Malawi, Rwanda, Uganda and Zambia (Namibia)) ~
[Eb4a] ~ Land-Use Information ~ Central Africa ~ Namibia ~
Most of eastern Namibia forms the Kalahari Desert (used as grazing land) (95K1). The Namib Desert stretching along Namibia's 1490-km. Atlantic coastline averages 97 km. in width (Area = 144,000 km2). It is one of the world's most barren regions (95K1). (la)
[Eb4b] ~ Land-Use Information ~ Central Africa ~ Rwanda ~
The latest (1994) of several genocides in Rwanda claimed over 900,000(?) people - 14% of Rwanda's population, the overwhelming majority of them Tutsis, but in northwestern Rwanda at least 5% of the residents were slaughtered even though there were no Tutsis. Rwanda contained 2040 people per square mile, twice the population density of the Netherlands (a nation that has far better soils, far more fertilizer and far greater ability to import food). The average Rwandan farmer worked 0.07 acre of land with agricultural practices not far removed from those of the Stone Age. By 1990, 40% of Rwanda's population was living on less than 1600 calories per day - famine level. A team of Belgian economists concluded that the outbreak of fighting "provided a unique opportunity to settle scores or reshuffle land properties, even among Hutus". It is not rare to hear Rwandans argue that the war was necessary to wipe out an excess population and bring numbers in line with the available land resources (
Cropland acreage increased from 26% to 45% of total land area during 1965-1987 ((90W1), p. 90).
Cumulative distribution of slopes on Rwandan fields (88L1) (la)
Rwanda's population = 6 million on 26,338 km2: population density = 494/ sq. mi. = 668/ sq. mi. of arable land (one of the most densely populated agricultural countries in the world (88L1).) Comments: Compare to US cropland slope profile (83L1) (Also see 80U2): 0-2% on 45%; 2-6% on 70%; 6-12% on 90%; 12-20% on 97%.
In Rwanda, 50% of all farming took place on hillsides by the mid-1980s (Ref. 16 of (97R1)). Comments: Interpreting this data requires a definition of farming, i.e. is grazing included?
Rwanda has under 0.03 ha/ person of arable land, most is on steep slopes (95D2).
[Eb4c] ~ Land-Use Information ~ Central Africa ~ Zaire (Congo) ~
About 25,000 km2 are cultivated land (1% of the total area of Zaire (Congo) (400 people/ km2 of cultivated land) ((56G1) p. 337).
Sub-Part [Eb5] ~ Land-Use Information ~ West Africa (Benin, Cameroon, Cape Verde, Cote D' Ivoire, The Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Sierra Leone) ~
Only 8% of the land area in the West African Sahel is suitable for farming. Irrigated agriculture currently occupies about 5% of the land (Siebert et al., 2005; Lotsch, 2006) (07N1). (Africa.doc)
To meet the growing needs for food and the limited availability of cultivatable land, farmers of the West African Sahel are expanding into marginal lands traditionally used by pastoralists, producing conflicts (07N1). (Africa.doc)
[Eb5a] ~ Land-Use Information ~ West Africa ~ Nigeria ~
Nigeria's harvested area has increased 2.5 times since 1950 ((78B2), p. 30).
In Nigeria's Benue River area farmers generally crop 3-6 years, then bush fallow for no more than 2 years in heavily populated areas. Fallow 10 years in sparsely settled areas (70V1).
Forested land in Nigeria was converted to agricultural uses at increasing rates over 1981-90. Such changes accounted for 25% of changes in forest cover during 1981-90 (95M1) (FAO data).
Sub-Part [Eb6] ~ Land-Use Information ~ Southern Africa (Angola, Botswana, Lesotho, Madagascar, Mauritius, Mozambique, South Africa, Swaziland, and Zimbabwe (formerly Rhodesia)) ~
[Eb6a] ~ Land-Use Information ~ Southern Africa ~ Zimbabwe ~
Zimbabwe's agriculture sector consists of a densely populated smallholder sector and a large-scale commercial (LSC) sector. The LSC sector occupies about 33% of Zimbabwe's land area and a disproportionately large share of high potential agricultural land. LSC farms are highly mechanized and show very high crop yields. Smallholder farms cultivate a much higher proportion of the arable area they occupy but show lower yields. These features reflect historical land allocations, stringent restrictions on farm subdivision, and the absence of an agricultural land tax (IFPRI Abstract, Research Report 128 (December 2002).
Zimbabwe's land distribution by rainfall: 1.8% of land gets over 39"/ year; 16.8% gets 33-39"/ year; 17.8% gets 26-33"/ year; 36.3% gets 18-26"/ year; 27.3% gets under 18"/ year (92T1) Total land area = 391,000 km2. Population = 9.5 million growing 3%/ year. 80% of population live in communal farming areas, while the rest live in large commercial farming areas and cities (92T1).
Ten years after independence from Rhodesia, Zimbabwe's 4200 white-owned commercial farms occupy the best lands, while 750,000 black farmers remained tied to the poor, rocky soils of the officially designated "communal lands" (90B3). Communal lands comprise 42% of Zimbabwe. Some 75% of "communal" lands are dry, hilly, isolated, and of value mainly for grazing - not crops (90B3).
Go to Top of this Review's Appendices (units, conversions, definitions)
Part [Ec] ~ Land-Use Information ~ North America ~ [Ec1]~Canada. [Ec2]~US Land Basics, [Ec3]~US Fallow Land, [Ec4]~US Floodplains, [Ec5]~US Cropland Inventory, [Ec6]~US Land-Use Inventory, [Ec7]~Changes in US Cropland Area, [Ec8]~Potential for Conversion to Cropland, [Ec9]~Conversion of US grass-lands to cropland, [Ec10]~US Croplands Maps, Tables and Charts, [Ec11]~Removals from the US Cropland Inventory, [Ec12]~US Forest Land Inventory Changes,
Sub-Part [Ec1] ~ Land-Use Information ~ Canada
The Canadian Land Inventory considers Land Classes 1-3 as arable. Almost all of Canada's Class 1-3 land is now being farmed. Canada's Class 1 lands are 2.33 times more productive than Class 4 land ((78B2), p. 31).
The Canadian prairie contains more than 80% of Canada's cultivated acreage, and generates the bulk of Canada's grain exports (87M1). A soil map of the 3 prairie provinces (Alberta, Saskatchewan, and Manitoba) is shown in Ref. (87M1).
Summer fallow in Canada (percent of cultivated land) (84S2) (la)
(The wheat-fallow rotation is blamed for declining organic matter content, increased erosion, and increased salinization of Canada's Prairie Provinces soil (84S2).)
Less than 9% of Canada's land is capable of being cultivated. Half of that area is currently being used to cultivate crops. The rest is pasture, forest, recreation land, transportation corridors and industrial- and urban land (Ref. 6 of (87I1)).
Of Canada's 9.22 million km2, 7% is farmland and less than 5% is improved land (86D1). Prime (Class 1) agricultural land occupies 0.5% of Canada's land area. "Dependable" (Class 1,2,3) cropland covers 5% of the land area (Ref.9, 19 of (86D1)). Canada's area of improved land has increased 0.5%/ year for the past 20 years (86D1).
The 3 Prairie Provinces of Canada had 220,000 km2 of seeded cropland, and 90,000 km2 of summer fallow in 1983 (90G2). (la) Small grain production for 1979-83 averaged 39 million tonnes/ year (20 million wheat, 11 M barley, 2M canola). 70% of national grain cash receipts (90G2).
[Ec1a] ~ Land-Use Information ~ Canada ~ Nova Scotia ~
In Nova Scotia some 5000 km2 was in cropland around 1900. That figure was reduced to 1790 km2 in 1981 (84S2). Comments: This is comparable to trends along the east coast of the US during that period.
[Ec1b] ~ Land-Use Information ~ Canada ~ Quebec ~
Corn area in Quebec increased by a factor of 5 in the past 20 years (84S2).
Sub-Part [Ec2] ~ Land-Use Information ~ US Land Basics ~
~ ~ US Farmland decreased by 2.9 million acres.
~ ~ 11,980 US farms went out of business
In 2004: Total land in US farms 936,295,000 acres on 2,112,970 farms
In 2005: Total land in US farms 933,400,000 acres on 2,100,990 farms.
~ ~ 95,410 US farms went out of business
~ ~ Farmland decreased by 29,115,000 acres
~ ~ In1995 there were 2,196,400 US farms: in 2005 there were 2,100,990 US farms
Allocation of US cropland area among various crops in 2006http://usda.mannlib.cornell.edu/usda/current/Acre/Acre-09-12-2006.txt
Crop- - | Acres~ ~ | Acres
- - - - | Planted~ |Harvested
Corn~ ~ |79,366,000|72,091,000
Wheat ~ |57,873,000|47,084,000
Cotton~ |14,940,000| - - - - -
Sorghum | 6,282,000| 5,317,000
Oats~ ~ | 4,312,000| 1,907,000
Rice~ ~ | 2,913,000| 2,895,000
Hay ~ ~ |62,697,000| - - - - -
Ref. (72U1) tabulates areas of all 50 US states (land, inland water, federal land, total area). Total area of US = 2271 million acres including Alaska (365.5 million acres) and Hawaii (4.1 million acres).
Sub-Part [Ec3] ~ Land-Use Information ~ US Fallow Land ~
As world wheat prices rose during the 1970s, US summer fallow land dropped from 170,000 km2 in 1969 to 130,000 km2 in 1974 ((78B2), p. 29). Fallow acreage in the US increased steadily until recently.
In 1973 the US had 125,000 km2 of summer fallow (Ref. 21 of (78M1)).
Between 1930-1973, US summer fallow acreage increased 2.6 times, even though the area of all crops declined from 1.7 to 1.56 million km2 (78M1). A map of regions of the US where summer fallow is commonly used is given in Ref. (78M1). Even with modern tillage methods, no more than 30% of all precipitation is stored in most dryland soils during an entire 21-month fallow period. Evaporation causes most of the precipitation loss (78M1).
The land in fallow in semi-arid wheat-producing areas of the US declined by nearly 50% during the 1970s, raising the potential for dust-bowl conditions ((78B1), p. 37). In recent years, 6.4 million acres (25,900 km2) of marginal (rainfall under 20"/ year) land in Montana and Colorado, and 27 million acres in the rest of the US have been plowed for crops. Federal crop subsidies seem largely responsible (83G1).
Until recently, as many as 240,000 km2 in the US have lain fallow as a result of payment-in-kind programs, annual set-aside requirements, and mandatory conservation (94L1).
US summer fallow (km2): 170,000 km2 in 1969; 130,000 in 1974 (84B2).
Sub-Part [Ec4] ~ Land-Use Information ~ US Floodplains ~
The USDA National Inventory of Soil- and Water Conservation Needs (1959-62) found floodplain area in the conterminous US was 134,156,000 acres. A 1973 US Corps of Engineers estimated US floodplain to cover 136,012,000 acres. In 1977 the US Water Resources Council estimated the US floodplain to total 178,822,000 acres. The 1977 NRI estimated US floodplains to total 175 million acres (85T2).
Sub-Part [Ec5] ~ Land-Use Information ~ US Cropland Inventory ~
In 1977 the US had 1.68 million km2 (649,000 sq. mi.) in crop production (83L1). Of the 421 million acres (1.70 million km2) of US cropland, 327 million acres are cropped, 165 million acres are affected by the highly-erodible-land conservation provisions of the 1985 farm bill (88M2). 118 million acres (478,000 km2) of US cropland are highly erodible (88M2). (la) Comments: Obsolete data - of historical value only.
1992 NRI Estimate of US Prime Farmlands (Areas are in units of 1000 km2) (94K2) (la)
Land Category - - | Area | Area | %~ ~ |% of 1992
- - - - - - - - - | 1982 | 1992 |Change| Area
All prime farmland|1375.6|1351.2| -1.8 |100.0
Cropland~ ~ ~ ~ ~ | 932.6| 873.1| -6.4 | 64.6
Pastureland ~ ~ ~ | 152.4| 148.8| -2.4 | 11.0
Rangeland ~ ~ ~ ~ | ~80.9| ~75.6| -6.5 | ~5.6
Forest land ~ ~ ~ | 184.6| 187.9| ~1.8 | 13.9
CPR Area~ ~ ~ ~ ~ | ~ 0.0| ~39.2| ~N.A.| ~2.9
Other Rural Land~ | ~25.1| ~26.7| ~6.3 | ~2.0
Cultivated acreage in the Plain States (million acres) ((82S1), p. 23):
There are 346 million acres (1.40 million km2) of "prime" (Class I and II) farmlands in the US, with 231 million (935,000 km2) of these being cropped in 1977 (79D1) (81G1) (USDA study).
US Croplands in 1977 (millions of acres) by Class (80U2)
Comments:Classes I and II are usually referred to as "prime". 345 million acres are prime farmland, but only 230 million acres (931,000 km2) are cropped. Of the remainder, 40 million are native pasture and pastureland, 22 million are rangeland, 42 million are forestland, and 11 million are "other" lands (80U2).
Distribution of US Croplands by Slope (la)
Line 1 is from (80U2): Line 2 is from (83L1)
(20-25% slopes (9-11 degrees) are considered the maximum that can be cropped in the US ((74C1), p.70).). Comments: China limits cropland slopes to about 25% (See elsewhere in this document.)
Farmland Categories in the US, a Historical Perspective (areas are in millions of acres) (81B1)
Cropland Area (million acres) by Soil Erosion Class and Land Use(1977 NRI (84H3))
Percentage distribution of US cropland acreage by soil erosion class and conservation practice (1977 National Resource Inventory(84H3))
Sub-Part [Ec6] ~ Land-Use Information ~ US Land-Use Inventories ~
Agricultural and Non-agricultural Uses of Land in the Conterminous US in 1974(Areas are in millions of acres) (79F2)
(100% =7.68 million km2)
# excludes forest lands duplicated in parks and other special-use land.
* Dept. of Defense and Nuclear Regulatory Commission lands.
*# marshes, swamps, bare-rock areas, deserts and tundra.
Land-Use Categories for 50 US States in 1978 (millions of acres) ((81U2), p. 418)
Of the US's 1400 million acres of rural, non-federal land, 422.8 million acres are croplands, 401.7 are rangelands, 394.4 are forested lands, and 59.9 are in minor land uses (89G2).
Trends in use of non-federal US Lands (Table 3 of Ref. (79D1)) (millions of acres)
Sub-Part [Ec7] ~ Land-Use Information ~ Changes in US Cropland Area ~
In the 1970s, US farmers (spurred by rising export demands) bought 50-60 million acres into production (83C1). In the 4 decades preceding 1970, US cropland area shrank. After 1970, US cropland area increased dramatically. More than 54 million acres were bought back into production (82O2).
During 1934-1984 in the 5 states IL, IN, IA, MO and OH, corn acreage increased from 30 to 40 million acres; soybeans increased from 0 to 31 million acres; oats and hay dropped from 29 to 11 million acres (85T3). New crop acreage increased 27% during 1967-1977 (83L1). Close-grown crops increased 4%, while rotation crops (hay and pasture) decreased 40% (83L1).
Since 1900, 125 million acres (506,000 km2) have been added to the US cropland inventory by bringing unused arable land into production, by irrigation and draining (76P2). US croplands increased 1.4 million acres during 1982-1987 (89G2). Idle cropland increased by 65 million acres during 1982-1987 (89G2).
In the 25 years after WWII, cropland area decreased by over 50% in New England and West Va., by nearly 50% in NY, NJ, PA, SC and GA, and by 1/3 in NC and VA. (82M2).
NRI 1992 Estimates of land uses and land-use changes in the US (Alaska excluded, Puerto Rico and Virgin Islands included) (94K2) (Areas are in 1000 km2)
Sub-Part [Ec8] ~ Land-Use Information ~ Potential for Conversion to Cropland ~
Some 127 million acres of US pasture, range and forestland were considered to have potential for use as croplands in 1980 (81B1).
About 25% of the land in the US is arable - 470 million acres, with about 81% of this (380 million acres) now under cultivation ((76P2), p.149). In 1977 the US had 344.5 million acres of "prime" agricultural land (230 million acres available for cropping and 114.5 million acres of pasture, range, and forest that could be converted to "prime" cropland (81B1).
About 50 million acres of this pasture, forest, etc. in the US in 1977 had medium-high potential for conversion to prime croplands. The remaining 65 million acres had zero- or low potential for conversion to prime farmlands due to field size, accessibility, and use as parks, etc. ((81G1), p. 37). 75 million additional US acres are potentially arable, but to develop this land would require draining swamps, irrigating deserts, and grading land (76P2).
In 1977 the US had 0.51 million km2 with high potential for conversion to croplands. Of this potential cropland, over 50% is susceptible to erosion. A USDA study contends that the entire US cropland base will be in production by 2000 ((83L1), p. 464).
Currently, 90 million acres (365,000 km2) now in pasture could be used as cropland (76P2).
Sub-Part [Ec9] ~ Land-Use Information ~ Conversion of US Grassland to Cropland ~
In late 1973-early 1974 in the US, 3.6 million acres switched from grassland to crops; 0.4 million acres switched from woodland to crops; 4.9 million acres switched from idle cropland and land held by federal programs to cropland, a total of 8.9 million acres (36,000 km2) added to the cropland base. Total soil loss on these acres (above that that would have occurred had the conversion not occurred) was 60 million tons. 13 million of these tons were by wind erosion (75G1).
Over 2 million of these 36000 km2 had inadequate conservation treatment. The average loss of topsoil to wind and water on this land was 2450 tonnes/ km2 (76E1). In the southern portion of the Great Plains that year, soil losses on 200 km2 of newly planted land ranged from 3100 to 28,500 tonnes/ km2 (76E1).
Grazed land (rangeland + pasture) in the US decreased by 8.3 million acres during 1982-1987. Of this amount, 2.7 million acres of rangeland, and 0.89 million acres of pastureland were converted to croplands (89G2). From 1978 to 1983, nearly 600,000 acres of fragile grasslands in eastern Colorado were plowed and converted to dryland wheat production. (325,188 acres of Class IV + 233,993 acres of Class VI + 12,884 acres of Class VII) (Ref. 5 of (84H2)) (Land in these categories is not considered suitable for sustained, non-irrigated cultivation.) More that 4.5 million acres of grassland may have been plowed in recent years throughout the northern and central Great Plains (Ref. 5 of (84H2)). (The reason is partly the reduced demand for beef and the increased demand for wheat.).
Sub-Part [Ec10] ~ Land-Use Information ~ US Croplands Maps, Tables, and Charts ~
A lot of useful maps, tables and charts on US farmlands is found in Ref. (80U2). (prime farmland and potential cropland by region, acres planted in major crops, cropland acreage in various slope categories, erosion-rate map of the US, wind erosion by state, average annual precipitation map, erosion rates for various land uses, use of non-federal land by capability class). Maps of 1977 US prime farmland, prime farmland in crops, prime farmland in pasture, prime farmland in rangeland, prime farmland in forest, etc. is found in Ref. (80H2). A plot of US cropland in actual production during 1910-1981 is given in Ref. (83B1). A map of the US showing locations of wheat, corn, grain sorghum, barley and oats-growing areas is on p.108 of Ref. (76H1). The percent of the labor force on the land is plotted against time (1820-1975). The number of US farms is plotted against time (1960-1974) (76H1). A map of the US giving the percent of the land in farms in 1945 is in Ref. (56A2).
Sub-Part [Ec11] ~ Land-Use Information ~ Removals from the US Cropland Inventory ~
Since 1900, 200 million acres (809,000 km2) in the US have been totally ruined for crop production by soil erosion, or have been so severely eroded that the land is only marginally suited for production (76P2). In the late 19th and early 20th centuries, 80% of the Piedmont region of the Southeastern US was cultivated, largely in cotton. Economic depression, boll weevil infestations, and erosion-related soil depletion led to widespread abandonment of cotton production (Ref. 25 of (88M1)). Today less than 25% of the Piedmont is in row crops. Pines and grasses, better able to utilize the remaining soil resources, are now the major crops (88M1).
Also see Chapter 6 on Urbanization of croplands.
In 1996 the US released for production the remaining land held out under commodity set-aside programs (97B2).
In 1994 the US returned, to production, all grain-land idled under commodity-supply management programs. Even with this land in use, and one of the best US harvests in memory, world grain stocks still fell (Ref.15 of (95B2)). The US still has 36 million acres (146,000 km2) in the CRP. This land typically produces 250 tonnes/ km2/ year (Ref. 16 of (95B2)) (Normal Midwest grain production is 800 tonnes/ km2/ year.).
In 1995, 7.5% of US corn-land and 12% of European grain-land were held out of production under commodity set-aside programs. If all this land had been in production it would have produced 34 million tons of grain (95B1).
Sub-Part [Ec12] ~ Land-Use Information ~ US Forest Land Inventory Changes ~
Forested land in the US increased by 800,000 acres (3240 km2) in the 5 years 1982-87 (89G2).
Go to Top of this Review's Reference List
Part [Ed] ~ Land-Use Information ~ South America and Central America ~ [Ed1]~Amazon Basin, [Ed2]~Brazil, [Ed3]~Andean Mountain Region, [Ed4]~Central America, [Ed5]~Southeastern South America,
Sub-Part [Ed1] ~ Land-Use Information ~ Amazon Basin ~
Only 1/3 of the Amazon Basin's 3 million miles2 (7.8 million km2) is suitable for cultivation - the savannas on the south rim and the terra altas (800-1100 ft. elevation) scattered throughout (89G1). 50% of Brazil is in the Amazon Basin (89G1). 1.4 million km2 of savannas are found in 4 of the Amazon countries: llanos of Venezuela, Cerrados of Brazil, llanos orientales of Colombia (See map of South America showing these areas on p. 93 of (90W1), p. 93). Savanna soils are highly acidic, have low nutrient content, and are erosion-prone when hilly ((90W1), p. 93). Savannas cover 2.5 million km2 of South America ((90W1), p. 116). (la)
Less than 5% (under 390,000 km2) of the Amazon Basin's 7.8 million km2 (overlaying 6 countries) is suitable for single-crop agriculture. Another 15% could support mixed tree cropping, and the remainder can produce medicine plants, rubber, fruit, nuts, and fibers (89D1).
Sub-Part [Ed2] ~ Land-Use Information ~ Brazil
The Esquel Foundation found that, between 1977-1994, the planted area of foodstuff production increased by 25% in Brazil's semi-arid lands (937,000 km2 total area). The region's average rate of reduction of agricultural productivity of foods (tonnes/ ha) is 2-3%/ year (2.6%/ year between 1977-1994) (
Brazil (8.5 million km2) now farms 470,000 km2, but could farm another 500,000 km2 for soybeans and wheat if aluminum toxicity problem could be solved (80S1). Brazil is now opening 500,000 km2 of acid soils on the Cerrado Plateau using lime and phosphate ((85A1), p. 409).
Agricultural land (cropland + grazing land) increased 0.8%/ year during 1986-1996 in Brazil (00F1).
Brazil (8.5 million km2) farms 190,000 km2 (250 people/ cultivated km2) ((56G1), p. 337). Soybean area in Parana state went from 4000 km2 to 20,000 km2 in the 1970s ((90W1), p. 43).
The Cerrados of Northeastern Brazil is secondary woody savanna. Savannas cover 1.5 million km2 of Brazilian cerrado ((90W1), p.116). (la) Caatinga is semi-arid, low, dense forest of woody and shrubby, spiny xerophytes (85L2). The Caatinga of Northeastern Brazil covers 800,000 km2. It consists of thorn-scrub vegetation in shallow soil. Most of the land is over-grazed and severely eroded ((90W1), p. 116). Comments: More recently, Brazilian soil scientists have learned how to make the Cerrado productive.
Sertao (nearly 3/4 of area of Northeast Brazil): Soils on crystalline rocks (3/4 of semi-arid region) are thin (1/2-1 m). 5% of Sertao is cultivated (subsistence) (85L2).
Sub-Part [Ed3] ~ Land-Use Information ~ Andean Mountain Region ~
[Ed3a] ~ Land-Use Information ~ Andean Mountain Region ~ Colombia and Venezuela ~
Savannas cover 300,000 km2 of the llanos of Colombia and Venezuela ((90W1), p. 116). (la) Comments: By comparison, Africa has about 10 million km2 of savanna - see elsewhere in this document.
Sub-Part [Ed4] ~ Land-Use Information ~ Central America ~
[Ed4a] ~ Land-Use Information ~ Central America ~ Costa Rica ~
In 1950, Costa Rica's arable farmland was 35% pasture. It was 54% pasture in early 1991, (91D1).
[Ed4b] ~ Land-Use Information ~ Central America ~ El Salvador ~
All arable land in El Salvador is now under cultivation. Farmers are being driven onto steeper slopes where erosion may require abandonment after 1-2 years of cultivation (76E1).
[Ed4c] ~ Land-Use Information ~ Central America - Jamaica ~
About 2/3 of Jamaica's bed rock is erodible limestone. Some 25% of Jamaica's surface area has slopes over 30%; 52% of the land has slopes over 20% ((82B3), Ref. 1 of (95P1)). (la) Jamaica's farmers commonly plant row crops on steep hillsides (82B3).
[Ed4d] ~ Land-Use Information ~ Central America ~ Mexico ~
Topography and uneven rainfall limit potentially arable land to 15% of Mexico. About 9% of Mexico was cultivated in the early 1970s (76W2).
A map of Mexican croplands and irrigated areas is shown on p. 130 of Ref. (76W2).
About 20% of all Mexican croplands are on steep slopes (Ref. 16 of (97R1)). (la)
Of the 46,705 km2 of croplands in 5 Mexican states in 1960, 47% was left fallow (due to lack of spring rains) or lost to drought. These fallowed areas are subject to wind erosion. An increasing body of evidence suggests that Mexico may be creating her own dust bowl through acceleration of wind erosion (70X1).
Sub-Part [Ed5] ~ Land-Use Information ~ Southeastern South America ~
[Ed5a] ~ Land-Use Information ~ Southeast South America ~ Argentina ~
Argentina Area Planted in Grains and Oil seeds (million acres) (from charts in 3/2/00 Wall Street Journal)
Argentinahas about 250,000 km2 of arable land and over 60,000 km2 in conservation tillage (99B1).
Part [Ee] ~ Land-Use Information ~ Europe and Australia ~ [Ee1]~Australia, [Ee2]~Europe,
Sub-Part [Ea1] ~ Land-Use Information ~ Australia
Australia has about 480,000 km2 of arable land, of which an estimated 130,000 km2 are in conservation tillage (96G2).
New Zealand has more than 50% of its total land area in permanent pasture (99B1).
Rainfall in Australia is highly variable. Frequent droughts last several seasons, resulting in massive die-offs (01B1) (02C1).
Australia's rangelands = 75% or 5.70 million km2 of Australia (01B1) (02C1). (la) About 4.06 million km2 of Australia's rangeland are used for grazing, with stock density running as low as one beast per 100 ha (01B1) (02C1). Comments: This is about the same as in the most arid grazing lands of the US (2-3 cows per sq. mile).
Problems with dryland salinity in Australia affect 25,000 km2, with 170,000 km2 of the 300,000 km2 (of dryland cropland) likely to be destroyed by salinity by 2050 based on current trends (01B1) (02C1).
Less than 300,000 km2 (less than 4%) of Australia's land are of good, or very good, quality in terms of broad scale cropping potential (02C1).
Total Australian land stock is 7.7 million km2 (01B1).
The majority of Australia is hot desert (01B1).
Australia is the world's driest habitable continent. It is exhausting its soils. According to the Division of Wildlife and Ecology of CSIRO, Australia's national research organization, the current population of 18.3 million is already close to consuming the entire continent's life-sustaining resources. The "ecological footprint" of modern Australians - the amount of good arable land needed to provide food, water, forest products and energy is 4.1 ha/ person. "Australia is short of good soils. Australia is an old weathered continent. Once the ecological footprint gets up to 3-4 ha/ person and the population hits 20 million, "we start to about equal our stock of reasonable soils" Australians treat the country like a slice of Europe, with scant regard for the fact that they live in "by far the smallest, flattest, driest, least fertile and climatically the most unpredictable continent" (Wilson da Silva , "Long dry spells, outlook gloomy", New Scientist 10/12/96).
Australia is an ancient land with very shallow infertile soils and low and erratic rainfall. It has very little arable land. The land is mostly desert, and is increasingly desertified each year. Its rivers are dying and it may soon not be able to feed the current population of 20 million, never mind the 50 million Australians feed overseas via exports. (See Mary White's books - Gondwana, the Greening of Australia; After the Greening the Browning; Listen, Our Land is Crying; and Running Down - Water in a Changing Land.)
About 10% of Australia's 7.7 million km2 can support crops and improved pasture (Ref. 6 of (91L1)).
Sub-Part [Ea2] ~ Land-Use Information ~ Europe
Cultivated land area in most European countries has been decreasing since the early 1980s at a rate of 3-12%/ decade, e.g. Austria 5.6%, Germany 3.7%, Ireland 12.2%, Italy 3.7%, Rumania 5.3%, and UK 7.7%. However the Netherlands has been increasing its cultivated area by 12%/ decade (99B1).
The EU's arable land base is about 1.48 million km2 (99B1).
Western Europe's area of meadows and pastures declined by 10% between 1970-88 (91O2). This decline was associated with the rise in (livestock) stocking rates (intensities) (03N1). Comments: Does this imply abandonment due to erosion?
In western European countries from the 1950s and 1960s onwards (80C3)(96B2), and in Eastern European countries since the 1990s, rural out-migration and restructuring of agriculture led to abandonment of steep slopes and other marginal land and reduced pressure to develop more land. Substantial areas of marginal land were abandoned and reverted to forest or scrub. In France this amounted to around 3%/ year in the 1960s and early 1970s (75F1). In Italy, around 1.5 million ha (15,000 km2) were abandoned in the 1960s, of which some 70% was slope land, with decreases of 20% in some provinces (80C3). The decline was very rapid, and closely related to sharp falls in agricultural employment (03N1).
In 1996 most of the 10% of idled EU cropland was returned to production (97B3).
The EU is reducing its set-aside area from 10% of its croplands in 1996 to 5% in 1997 - an addition of 20,000 km2 to the EU's cropland base (97B1).
Between 1969-1971 and 1983, EEC-10's agricultural (farmed) area declined by 45,000 km2, EEC-12 declined by 60,300 km2. Woodland area increased 12,000 km2 (87L3).
Cropland in France, Italy, and Spain decreased by 59,000 km2 from 1965-84 while forested area increased by 64,000 km2. Thinks most change in 1960's and 70's. With increased crop production/ ha, land abandonment will occur more rapidly in future (90L2).
Eastern European nations have been hard-pressed to maintain their cultivated-land area over the past 15 years ((78B2), p. 34).
About 50% of Western Europe is unsuited to food production, implying 1.5 acres (0.61 ha.) of arable land/ person (74C1). The OECD Agriculture Committee reports that opportunities for new land reclamation in Western Europe are negligible ((78B2), p. 34).
About 25% of EEC-12 is level (0-8% slope), 14% level/ sloping (0-15% slope). About 26% is moderately steep/ steep (15- 25+% slope) (87L3). (la)
Greece, Italy, and Spain have 65, 56, and 42%, respectively of land in the moderately steep (15- 25+% slope) - and steep slope (25+% slope) category (87L3). Comments: 25% slope is probably the far upper limit for croplands - this is around China's upper legal limit.
[Ea2a] ~ Land-Use Information ~ Europe ~ European Mediterranean countries ~
During 1965-1984, the area of cultivated land in European Mediterranean countries decreased 8% (59,000 km2). Forests increased by 14% (64,000 km2) (89L3).
LeHouerou estimates that cultivated land area in European Mediterranean countries has decreased by 66,000 km2 in the last 20 years. Of these, 20,000 km2 were taken from area devoted to cereals (but total yields have increased). Orchards and vineyards increased by over 10,000 km2; forests and shrubland increased by 64,000 km2 (87L2).
[Ea2b] ~ Land-Use Information ~ Europe ~ Norway ~
Some 4% of Norway is cultivated. Agriculture is stable in spite of steep slopes (which are kept in grass or legume crops most of the time ((74C1), p. 182).
[Ea2c] ~ Land-Use Information ~ Europe ~ Serbia (central) ~
Some 87% of Serbia's cropland is on slope over 5 degrees, and 79% is on slope over 10 degrees (90D3). (la) Severe water erosion is evident on sloping cropland (90D3).
[Ea2d] ~ Land-Use Information ~ Europe ~ UK (South Downs) ~
In South Downs in the UK, soil thickness (loess over limestone) rarely exceeds 20 cm (90H3).
SECTION (2-F) ~ Climatic Data ~
Aridity maps of Australia, Africa, Eurasia, North America and South America are on pp.1-6 of Ref. (70D1). Classifications: "extremely arid", "Arid" and "Semi-Arid".
A map of global variations in soil moisture (mm.) is on p.169 of (90W1).
The Tsetse fly virtually excludes draft animals from 10 million km2 of Africa (87H1).
A map of average precipitation in the US is on p. 452 of Ref. (80H1).
A map of average precipitation in the US, + Alaska, is on p. 20 of Ref. (80U2).
A map of average runoff in the US is on p. 453 of Ref. (80H1).
Laboratory studies under favorable conditions indicate that enhanced CO2 levels can improve growth rates and water utilization of crops significantly (89M3). Under field conditions, estimated increase in yields are projected to be 25-33% of that observed in the controlled greenhouse conditions (92B3). This is without taking into consideration other consequences of climate change, so yields may, in fact, not improve at all (92B3).
Of 200 plant species studied, two thirds show a sensitivity to ozone damage (89U6).
In 1988 the US experienced the hottest year on record to that time which, accompanied by a mid-continent drought, resulted in a 30% decrease in grain yield. Canadian production dropped 37% (90U4). Comments: The heat was accompanied by drought that probably did most of the damage. The above is one argument for avoiding global warming - land heats up faster than oceans, resulting in increased aridity.
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