Geographical Distribution of Crops - Part-2 Introduction, Crop Production | Crop Production Notes- Agricultural Engineering PDF Download

physiologies: Sugar cane is a C4 crop, while sugar beets are C3, and in sugar cane the sugar is stored in the stalk, while in beets it is stored in the roots. The two sugar crops together take up slightly more than 2% of the cultivated croplands in the world. Sugar beets are cultivated in the temperate latitudes of the Northern Hemisphere from 40
N to 60
N, mostly in Europe and the European part of Russia (Figure 4d), while sugar cane is a tropical crop, cultivated mostly in the Caribbean and Florida, but also in Central and South America, India, and other parts of south Asia (Figure 4d). Minor cultivation areas for sugar beets can also

be found in the American midwest and the northeastern tip of China, while sugar cane is also grown in Australia and South Africa. 4.4. Pulses [28] The FAO defines pulses as a group comprised of dry beans, dry broad beans, dry peas, chick-peas, dry cow peas, pigeon peas, lentils, bambara beans, vetches, and lupins.

Pulses are very important economically and provide us with food, medicines, oils, chemicals, timber, dyes, and ornamental garden plants. They also have extremely high dietary

value because they contain a higher percentage of protein than most other plant foods. [29] Most pulses prefer warm climates, but there are varieties that grow in temperate regions. Pulses are broadly cultivated from 60
Nto50
S (Figures 4d and 5f). On a global scale, they occupy 4% of the cultivated land and, as a group, they rank third in cultivation area, after cereals and oil-bearing crops. The most intense cultivation of pulses occurs around 25
N (in India, where census data on a dozen different kinds of lentils were collected), but pulses are also cultivated throughout Europe, parts of western Asia, the eastern half of China, Australia, the Rift Valley in eastern

Africa, the southeastern states of Brazil, Central America, and even in Canada. 4.5. Oil-Bearing Crops [30] On a global scale, oil-bearing crops are grown over 10% of the cropland. According to the FAO, 10% of the total calories available for human consumption are derived from oil-bearing crops such as soybeans, groundnuts (or peanuts), rapeseed (or canola), sunflower and oil palm fruit.

This percentage is slightly higher for developed countries (12%) and slightly lower for developing countries (9%).

While oil-bearing crops are used mainly for processing into

oil (about 79% of the world production), they are also used for direct food consumption (11%), for seed (2%), for feed (5%), and for industrial use (almost 1%), and 3% are wasted [FAO/GIEWS, 2001].
[31] Oil-bearing crops exhibit a distribution pattern similar to that of cereals: Soybeans, rapeseed (or canola), and sunflower prefer temperate latitudes, while groundnuts (or peanuts) and oil palm fruit are their equatorial and tropical counterparts (Figure 5g). Soybeans occupy
5% of the world’s croplands, while rapeseed/canola and sunflower each occupy
2% of the world’s croplands, groundnuts occupy 1%, and oil palm fruit occupies less than 1% of the world’s croplands. [32] The cultivation of soybeans, especially in North and South America, has been increasing rapidly in recent years, and this was the only crop that had a strong positive growth trend in the 6 years of census data collected. Soybeans are also unique in being the only oil-bearing legume. According to the FAO/GIEWS [2001], Asia and the Americas are the largest producers of oil-bearing crops. These crops amount to 50 and 34%, respectively, of the agricultural production of the two continents. Soybean rivals maize for domination in the maize belt of North America, but is also prevalent in central South America (southern Brazil and northern Argentina), eastern China, and central India (Figure 4e). The soybean belt in the United States alone is roughly the size of Bolivia (or 1.1 million km2). [33] Peanuts are grown in the southeastern United States and eastern China, but the greatest intensities are found in southern India and Gambia (Figure 4e). Rapeseed (or canola) is most prevalent in the southern Canadian provinces, but the crop is also cultivated extensively in the entire continent of Europe, in northwestern India, and in southeastern China (Figure 4e). Sunflowers are grown in southeastern Europe and the European part of Russia (Figure 4f), while oil palm fruit is characteristic of some equatorial nations, including Malaysia and Indonesia, and western Africa (Figure 4f). 4.6. Cotton [34] Cotton is the only major fiber considered here and the only non-food crop. It is cultivated over 3% of the croplands, mostly around 30
N (in the southeastern United States and Uzbekistan, and in Tajikistan, where cotton is the major agricultural commodity) and around 20
N (in India and Pakistan) (Figures 4e and 5). Smaller areas of cotton cultivation can also be found throughout southern

South America, the southern half of Africa, and in Australia. 4.7. Other Crops [35] While the top five major crops together constitute 65% of the cropland, this is not necessarily true for a few regions: the Caribbean, central Africa, East Asia, eastern Africa, Oceania, southern Europe, and western Africa (Table 5). To describe the agriculture of these regions better, we present the top three minor crops (Table 5). The top three minor (or other) crops add up to 26% of the cropland in southern Europe, 15% in central Africa, and 14% in the Caribbean. [36] Of the ‘‘minor’’ crop groups, the most dominant are fruit (with slightly more than 3% of the world’s croplands); other oil-bearing crops such as coconut, olives, safflower, sesame, and linseeds; other cereals such as oats and mixed grains; and other crops such as coffee, tobacco, and cocoa (all with slightly less than 3% of the world’s croplands) (Table 5 and Figure 6). Vegetables, other roots and tubers, nuts, other fibers, and spices each take up less than 2% of the world’s cropland area. [37] On a global scale, several minor crops have areas of cultivation larger than some of the chosen major crops. With over 220,000 km2, oats, a minor cereal, is 1.5 times larger in extent than rye, a major cereal. Coffee and coconuts are each cultivated over slightly more than 100,000 km2,an area larger than that of both sugar beets and oil palm fruit, both of which are considered major crops. Sweet potatoes cover an area of 90,000 km2, but their extent is half that of potatoes. Grapes and olives, each with over 75,000 km2,are two other regionally significant crops that cannot be disregarded on a global scale either.
5. Diversity of the Major Crops [38] Crop diversity is a critical factor in food security because having a variety of crops allows for the possibility

Table 6. Area and Relative Proportion of Seven Crop Groups Crop Groupa Area, 1000 km2 Relative Fraction, % Cereals 10,955 61 Roots and tubers 734 4 Sugar crops 419 2 Pulses 794 4 Oil-bearing 1,819 10 Fibers (cotton) 534 3 Others 2,664 15 Total cropland 17,920 100 a The crop groups here are comprised only of the 18 major crops considered in the study. All other crops are included in the ‘‘Others’’ group.

Figure 7. Degree of diversification of agricultural commodities. Here we map an Agricultural Commodity Diversification Index (ACDI), which is based on the ratio of the relative crop fraction of existing crops to the average mean relative crop fraction (see text for details). This data set only represents the diversification in cultivation of the selected major crops in this study. See color version of this figure at back of this issue.

that at least some crops will survive despite a poor climate, insect outbreaks, or other natural disasters. Social factors such as civil or economic strife, trade imbalances, and others can compound natural disasters to further threaten food security. [39] For a quantitative evaluation of the global distribution of the diversity of our chosen major crops, we define an Agricultural Commodity Diversification Index (ACDI). This index is based on the ratio of the relative crop fraction to the average crop fraction of the crops that exist in each grid cell.

For each grid cell (i), the ACDI is calculated as follows:

climate than that of the maize belt. Soybeans are planted slightly later than maize (May through June) but harvested around the same time (October through November) [USDA/ JAWF, 1994]. Throughout the soybean belt, the secondary crops are cotton and wheat. [49] The other important crops in North America are barley (which together with wheat forms a wheat-barley belt in the Canadian province of Alberta) and cotton (which dominates the cropland along the Gulf Coast with the exception of Florida, and forms a cotton or cotton-sorghum belt in Texas and cotton-groundnuts belt in Georgia).

Florida is dominated by sugar cane, making this region agriculturally similar to the rest of the Caribbean, rather than to continental North America. The state of Georgia also contains a small groundnuts belt. 6.2. Central America and the Caribbean [50] Central America has varied agroclimatic settings.

However, a single crop, maize, dominates the region from central Mexico to Nicaragua inclusively (Figure 8a). In the dry climate of northwestern Mexico, maize is planted in September and October and harvested January through March of the next year [USDA/JAWF, 1994]. In Mexico, maize forms crop belts with three other crops: sorghum in the state of Tamaulipas, pulses in Coahuila, and wheat in Sonora. Throughout the Central American maize belt, pulses are the next most dominant crop, followed by sugar cane. [51] Costa Rica’s croplands are a transitional area with a mixture of maize, pulses, and rice being cultivated throughout the country (Figure 8a). Rice forms a much smaller second crop belt in Costa Rica and Panama, with maize as the secondary crop, although the average annual temperature and precipitation in this region are not much different from those to the north. The Caribbean is dominated by sugar cane (Figure 8a). In this region with a steady yearround climate, sugar cane is planted and harvested almost throughout the entire year (November through May) [USDA/JAWF, 1994]. Rice and maize are the secondary crops throughout the Caribbean. Although not considered a major crop in this study, coffee is a key commodity in the Caribbean and accounts for 7% of the cultivated land (a percentage higher than that of the third most dominant major crop). 6.3. South America [52] South America has far more diverse cultivation than North and Central America (Figure 7). Here maize and soybeans rival for dominance in the northern portions of the continent, while wheat dominates in the south. [53] One maize belt is draped over the entire Andes and the lowlands to their west from the Columbian highlands all the way into Argentina’s Patagonia, and another centers on the Brazilian Highlands in southeastern Brazil (Figure 8a).

Here maize is planted March through May and harvested October through December [USDA/JAWF, 1994]. While maize is a major dominant crop in Central America, the Andes, and the Brazilian Highlands, it is surpassed by wheat and soybeans in the La Plata region of South America.

Throughout the Andean maize belt the secondary crops

are rice (in the Columbian and Ecuadorian lowlands west of the Andes), potatoes (throughout the Peruvian and Bolivian Andes), and sunflowers (in the southern Andes of Argentina). In the Brazilian Highlands, sugar cane and soybeans complement the maize belt. [54] Soybeans form the next largest belt in South America (Figure 8a). This crop is extensively cultivated in the central portion of the continent from the Brazilian state of Mato Grosso in the north to the Argentinean state of Cordoba in the south, in the Gran Chaco region and the area east of it.

Soybeans in this region are planted in the beginning of the wet season (October through December) and harvested at the end of it (March through May) [USDA/JAWF, 1994].

The secondary crops throughout this soybean belt are maize in Brazil, cotton in Paraguay, and a combination of wheat, maize, and sunflower in Argentina. [55] Wheat forms the third largest crop belt in South America, but it is the major crop in the southern part of the continent in Argentina and Chile (Figure 8a). Wheat covers the pampas of Argentina and the Western Coastal Plain of Chile. As opposed to the maize and the soybean cultivation areas in South America, the regions of wheat cultivation do experience frosts. Wheat in this region is planted May through July and harvested mid-November through mid-January [USDA/JAWF, 1994]. Throughout the South American wheat belt in the pampas of Argentina, soybeans and sunflowers form the secondary crops, while throughout the South American wheat belt in Chile, the secondary crop is maize. [56] In addition to maize, soybeans, and wheat, there are several other major crop belts in South America. Although sunflowers are cultivated in other parts of the world, South America has the only sunflower belt (Figure 8a). In fact sunflowers are the third-ranking crop in southern South America, surpassing maize, with 12% of the cropland. Also, the northern coastline of the continent and the Tocantins river basin are regions of rice cultivation, while the Xingu´ river basin is a region of cassava cultivation (Figure 8a). In Brazil the region between Serra do Piaui and the town of Recife makes up a small pulses belt, while south of Sa˜o Paulo has a sugar cane belt (Figure 8a).

6.4. Europe [57] Europe, like North and Central America, is also composed of large homoge neous agricultu ral zones (Figure 7). The top five most common major crops for the continent as a whole (wheat, barley, maize, potatoes, and sunflower) represent 63% of the croplands (Table 5). The top five most common major crops for the continent as a whole (wheat, barley, maize, potatoes, and sunflower) represent 63% of the croplands (Table 5). Most locations in Europe can benefit from two harvests. Winter grains (winter wheat, winter barley, and rye) are planted September through October and harvested mid-June through August of the next year, and spring grains (maize, spring barley, and most oats) are planted April through May and harvested September through October of the same year [USDA/JAWF, 1994]. [58] Wheat is cultivated across the entire European continent, except for the Iberian Peninsula, Belarus, and the Baltic Republics (Figure 8b). While most of the wheat 

cultivated throughout this region is winter wheat, durum wheat is also grown here. Winter wheat is most often cultivated in combination with winter barley and rye, and is also most often cultivated on the same land (doublecropped) with maize, oats and to a lesser extent with spring barley [USDA/JAWF, 1994]. Throughout southern Europe, spanning France, Italy, Hungary, Moldova, and all countries south of there, the secondary crop is maize. To the north, in Croatia, Bosnia and Herzegovina, northern Serbia, and Romania, can be found a maize-wheat belt. In Poland, the much more cold-tolerant rye can be found as the secondary crop. In this northern sub-region, barley and rye are also found. Throughout Poland, the Russian oblast of Nizhny Novgorod, and the surrounding regions the croplands can be described as a mixture of wheat, barley, rye, and potatoes. [59] Second in size in Europe is the area of barley cultivation (Figure 8b). Winter barley is the dominant crop on the Iberian Peninsula, especially in Spain, and is surrounded by barley-wheat and wheat alone belts. The spring barley belt is found in Belarus, the Baltic Republics, and the European part of Russia. Ireland stands alone in having both spring and winter barley cultivation. Throughout the barley belts, the secondary crops are wheat, potatoes, and rye. [60] The region along the Mediterranean Sea has a distinct climate. While wheat and barley are the top crops, a minor crop, olives, occupies a large portion of the region’s cropland (over 43,000 km2 or 15%). In this region, fruits come next in the other categories with 40,600 km2, of which area 65% is in grapes, 7% in oranges, and 6% in peaches and nectarines. 6.5. Africa [61] With 13% of the global harvested area, Africa has less cropland than any other part of the world. The agroclimatological zones in Africa are very diverse, ranging from the dry and barren desert, through the rich soil of the Rift, Nile, and Niger Valleys, to the southern extremes. But unlike any other parts of the world, there are no large crop belts in Africa.

Rather, there are agricultural regions within which different combinations of crops are cultivated (Figure 8b). [62] Northern Africa is characterized by a Mediterranean climate with the alternation of pronounced warm dry and cool wet seasons. Morocco, Algeria, Libya, and Tunisia have large crop areas along the coast, dominated by a mixture of wheat and barley (Figure 8b). With a single growing season, both winter wheat and barley are planted November through December and harvested May through June of the next year [USDA/JAWF, 1994]. In the Nile delta and Nile Valley, wheat, maize, and rice form a unique agricultural belt (Figure 8b). Again, akin to southern Europe, olives are a major crop in this region, representing 11% of the cropland. [63] The Sahel region, with low rainfall, is dominated by the drought resistant millet and sorghum. In Senegal, Gambia, and Guinea-Bissau another drought resistant crop, groundnuts or peanuts, is grown. Maize and a mixture of other crops are also found in northern Nigeria (Figure 8b).

With a single growing season in the Sahel, most crops are planted May through July and harvested October through

November [USDA/JAWF, 1994]. Coastal West Africa has a more moderate climate because of the oceanic influence and thus benefits from two growing seasons. The dominant crops here are hydrophilic: rice from Guinea to Liberia and maize from the Ivory Coast to Nigeria. Here the first crop of rice is planted April through May and harvested August through October, and a second crop of rice is planted November through December and harvested March through April. Maize is also cultivated in two crops, with the first one being planted March through April and harvested June through August, and the second being planted August through September and harvested December through January [USDA/JAWF, 1994]. The secondary crop throughout Africa’s West Coast rice belt is cassava, while in the maize belt it is a mixture of sorghum, rice, cotton, and millet. Since the agricultural area along the western coast of Africa is much smaller than the one in the Sahel, rice is not one of the top five crops in Sahelian Africa (Figure 6).

However, maize is the third most dominant crop, after sorghum and millet, occupying 11% of the cropland in this region (Table 5). [64] Directly east of the Sahel, in Ethiopia, is the northern tip of the African Rift Valley. Throughout the Rift Valley, maize is the dominant crop (Figure 8b). The only locations where maize is not dominant are Zaire (where cassava and cassava-maize-pulses are the prevalent combinations), Mozambique (where cassava dominates), and the drier Botswana and Namibia (where sorghum and millet, respectively, are the crops of choice). Throughout eastern Africa, maize is a winter crop generally planted March through June and harvested August through December, while in South Africa, maize is a summer crop planted October through December and harvested April through June. With water being the limiting factor throughout eastern Africa, the secondary crop is cassava (in Tanzania, Angola, Zambia, and Mozambique), pulses (in Uganda and Tanzania), sorghum (in Mozambique), and cotton (in Zimbabwe, with somewhat better irrigation facilities). South Africa, on the other hand, benefits from a second crop of winter wheat that is planted May through July and harvested October through December [USDA/JAWF, 1994]. The island of Madagascar benefits from two growing seasons, and the most dominant crop is rice, followed by cassava and maize. Rice here is planted November through mid-January and harvested April through June. The two winter crops in this area are wheat and sweet potatoes. The former is planted in May and harvested in November, and the later is planted mid-February through mid-May and harvested mid-May through midDecember [FAO/GIEWS, 2001]. There is a ’’minor’’ crop that should be included for a more complete regional picture; plantains occupy a significant portion of the croplands in both eastern and central Africa, representing about 6% of the cropland (Figure 6 and Table 5). 6.6. Middle East [65] The dominant crop in the Middle East is wheat, cultivated from Turkey in the west to Iran in the east and along the Mediterranean coast, briefly interrupted by a combination of barley and wheat in Syria (Figure 8b).

Winter wheat and barley are planted mid-September 

through December and harvested April through August [USDA/JAWF, 1994]. With a far smaller proportion (7% of the cropland) pulses are the third major crop in the Middle East, cultivated in the summer together with maize in northern Turkey, with cotton along the Turkey-Syria border, and with sunflowers in western Turkey.

6.7. Asia [66] Rice dominates this region with 24% of the cropland.

The Asian rice belt stretches from India and Nepal on the west to Japan, South Korea, and Taiwan on the east, from the Yangtze River in the north to Timor in the south (Figure 8c).

This area receives ample precipitation from the monsoons.

Throughout this region, farmers plant a single crop of rice in April and May and harvest it in August through October; however, several sub-regions plant multiple crops of rice [USDA/JAWF, 1994]. Rice is double cropped in southeastern China, along the final stretches of the Xun Xi River, throughout most of Indochina, in the eastern half of India and the Ganges floodplain, and on the island of Java.

Throughout parts of Bangladesh, in the Ganges-Brahmaputra floodplain, three crops of rice are cultivated. This large crop belt is dominated almost exclusively by rice, but there is a large number of diverse secondary crops: wheat, maize, groundnuts, and sugar cane in China; maize, cassava and pulses in Indochina; wheat in Nepal; wheat, pulses, and groundnuts in India; and maize in Indonesia. [67] With only a slightly smaller area (19% of the cropland), wheat forms the second largest crop belt in Asia.

This crop is characteristic of the Indus River Valley in Pakistan, the Huang He River Valley in China, and most of Central Asia with the exception of Turkmenistan, Uzbekistan, and the southern parts of Kazakhstan (Figure 8c). In Pakistan and northwestern India, winter wheat is planted October through December and harvested March through May. In the Huang He River Valley, spring wheat is planted in March and April and harvested in mid-July through midAugust, but winter wheat accounts for 85 – 90% of the wheat and is planted mid-September through October and harvested in June. In Kazakhstan and the Russian oblasts north of it, winter wheat is planted in September and harvested mid-July through August, but spring wheat is the larger crop and is planted in May and harvested midAugust through September [USDA/JAWF, 1994]. Unlike in the Asian rice belt, secondary crops are far fewer in the wheat belt. In the Indus River Valley, the major secondary crop is cotton, in the Huang He River Valley it is maize, and in Kazakhstan and the Russian oblasts north of it the major secondary crop is barley. [68] In Asia, maize is grown in small pockets of dominance (Figure 8c). It is the dominant crop in two of the northeastern Chinese provinces of Jilin and Liaoning. To the north, this area transitions into a maize-wheat-soybean area and then into a soybean-maize-wheat area, while to the west, it progresses into a wheat-maize and later into a wheat cultivation area. The secondary crop throughout this area is rice. China has another maize pocket in the southern province of Yunnan; this stands alone in the middle of the Asian rice belt, and the secondary crop here is wheat.

Finally, together with rice, maize forms the dominant crop

combination in the Philippines, where cassava and sugar cane compete for third and fourth place. While for Asia as a whole, maize represents 7% of the cropland, this crop is one of the top five only in East and Southeast Asia (Table 5 and Figure 6). [69] Together with rice and wheat, pulses form a dominant crop complex in western India. In Asia as a whole, they represent 6% of the cropland, but in India, this proportion is 12%. Here they are the third most important major crop after rice and wheat, and the area they cover is about half that of rice and about equal to the area of wheat. Pulses are also the secondary crop in Myanmar and a tertiary crop in North Korea and several southern Russian oblasts. [70] Several other crops form a number of small crop belts (Figure 8c). Potatoes dominate in far northeastern Russia, barley is the most dominant crop in parts of southeastern Kazakhstan, a combination of cotton and wheat dominates Uzbekistan, and oil palm fruit stands out in Malaysia. India alone has the most diverse combination of crop belts.

Groundnuts stand out in Gujarat; millet in Gujarat and Rajasthan; a combination of pulses, rice, and wheat exists in Madhya Pradesh, with the agriculture of the rest of this state being a mixture of more than three crops; sorghum dominates the state of Maharashtra; while rice spreads along the southern and eastern coast. 6.8. Australia and New Zealand [71] The agriculture of this region closely resembles that of the other temperate regions of the world. Wheat dominates Australia (Figure 8c); it is interrupted only briefly by a combination of wheat and barley in the area around Adelaide. Winter wheat here is planted May through July and harvested October through December [USDA/JAWF, 1994].

In the western portion of the Australian wheat belt, pulses are the most prominent secondary crop, while barley is the secondary crop in the eastern portions. Winter barley is also the most dominant crop in New Zealand, forming its own belt there; it is planted April through June, and harvested November through January. Wheat is the secondary crop in New Zealand. Pulses are the third crop category with a significant enough proportion to be included here (11%). 7. Summary and Conclusions [72] Agricultural activities have been one of the most important drivers of global environmental change in recent decades and centuries. To assess the consequences of cultivation practices for global food production and the health of the environment, data sets of the worldwide extent and intensity of agricultural land use and land cover change are critically needed. While remotely sensed data are able to delineate some of the patterns of agricultural land cover, they are unable to distinguish some of the important features of agricultural land use practices such as the different types of cropping systems (crop varieties, crop rotations, intercropping, multiple cropping), agricultural inputs (irrigation, fertilization, machinery), and outputs (yield, production).

Such information is critically needed for studying the consequences of food production systems on the global biogeochemical cycles, global and regional climate, and 

food security; only ground-based data sources, such as agricultural censuses, contain the necessary information. [73] In this study we have synthesized crop specific agricultural census data and spatially explicit data on the extent of the world’s croplands to generate global data sets for the distribution of 18 major crops. Although the study uses a simplified approach with several assumptions, it succeeds in producing a ‘‘first cut’’ global data set that is generally consistent with common agricultural knowledge.

Quantitative validation of the data set has not been possible due to the lack of good alternative data sources for many regions of the world. However, we have qualitatively compared our data sets to a recent publication on the distribution of major crops of the world by the U.S.

Department of Agriculture; the comparison reveals the major consistencies between the data sets, as well as the deficiencies in our approach. [74] This study shows that the selected 18 major crops (barley, maize, millet, rice, rye, sorghum, wheat, cassava, potatoes, sugar beets, sugar cane, pulses, soybeans, groundnuts/peanuts, rapeseed/canola, sunflower, oil palm fruit, and cotton) are representative of the agriculture of most regions in the world. In certain regions however, one would need to include other crops to obtain a more complete picture (i.e., oats for many parts of the world and grapes and olives in the Mediterranean) (Table 5). Using the crop cover data, we were able to objectively delineate the major crop belts of the world (Figure 8). The location of these crop belts is also in concert with the rest of the agricultural literature. Some continents are composed of large agriculturally homogeneous zones (North America, Europe, Asia, the Middle East, Australia, and New Zealand), while others truly are tapestries of crop mixtures (South America and Africa). [75] These crop data sets have a wide range of applications. They can be used within global ecosystem models and climate models, to assess global food production systems (food production, food security), global water use (irrigation water requirements, impacts on water quality), and consequences for global climate and biogeochemical cycles.