1. HIST 480: CAPSTONE SEMINAR
FINAL PAPER
INTERESTING FINDINGS ON THE USE OF SWEET POTATO AND MAIZE IN
CHINA: A STUDY OF THE ONGOING IMPACT OF THE COLUMBIAN
EXCHANGE
MAX GOLDMAN
4/29/2015

2. Given an ever-expanding understanding of the specious present, historians have
sought to explain the origins and historical development of the globalized world of today
through new lenses. Such an approach seems to have been adopted by the likes of Alfred
W. Crosby and Charles Mann, historians who were instrumental in fostering in students
of history radical new ideas regarding the beginnings of the world we are so familiar with
today. In their narratives, these historians have attempted to argue that European contact
with the New World produced a chain reaction leading to 1) the deaths of millions of
Natives, the ecological devastation of American environments by European animals
along with the Old World reaping the fruits of the Americas leading to the former’s
population growth, 2) Europe’s ecological and biological conquest of Neo Europes in the
Americas and in Oceania and 3) the origins of global ecological, biological and cultural
homogenization. What these trios of historians do not illustrate sufficiently is the role of
the Columbian Exchange- specifically the introduction of the sweet potato and maize- on
20th century China.
As an aspiring historian of China and East Asia, I was initially drawn to the
methodology employed by historians Dennis Flynn and Arturo Giraldez. Though focused
on the silver, I found this following statement to be of critical importance in describing
the important role of China, be it in a “Columbian Exchange” or otherwise.

3. We intentionally emphasize the role of China and its tributary system… because
the scholarly literature in general has neglected this pivotal country, certainly in
recognizing China as a prime causal actor.1
According to J.S. Cooley, the sweet potato’s origins are shrouded in mystery.
Specifically, he notes, “no single wild species has been found that is definitely known to
be the plant from which the sweet potato derives.”2 Cooley further comments that the
plant is not known to be native to any regions other than tropical America and its
islands.3 However, Cooley also points out that prior to European contact, sweet potatoes
served an important function not only for the peoples of “tropical America but also for
the Maori of New Zealand, leading some anthropologists to theorize that the crop
originated in New Zealand.”4 Andrew Lawler would support this claim, and argues that
as masters of the sea, Polynesians were able to establish permanent biological contact
with South America, and thus were able to introduce sweet potatoes to Oceania.5 Alfred
W. Crosby would also point out that “sweet potatoes along with white potatoes allowed
the Maoris to gain the means to produce large quantities of food” and enter into a
European created world market.” 6
In his book The Columbian Exchange, Crosby provides an empirical illustration
of the historical significance of the sweet potato crop to the Old World, along with
1 Dennis Flynn and Arturo Giraldez, “Born with a Silver Spoon: The Origin of World Trade n
1571”, Journal of World History, Vol.6,No. 2 (1995), 201-219, 202.
2
J.S. Cooley,” The Sweet Potato: Its Origins and Primitive Storage Practices”,Economic Botany,
Vol.5, No.4. (1951), 378-386, 379.
3
Ibid., Also significant is that early historical literature documenting the “sweet potato” does not
clearly distinguish between the yam or the sweet potato.
4
Ibid., 381.
5
Andrew Lawler, “ Beyond Kon Tiki: Did Polynesians Sail to South America?”. AAAS, Vol.
328, No, 5984 (June 2010), 1344-1347: 1345.
6
Alfred W. Crosby, Ecological Imperialism: The Biological Expansion of Europe,900-1900,
new Ed( New York, NY: Cambridge University Press,2004), 230. I conclude that Crosby
would point out that New Zealand’s climate and soils were “nearly ideal”. Such is likely to be a
major factor in the success of sweet potatoes in New Zealand.

4. several others. In a chart titled “Varieties of Old and New World Staples” (in millions of
calories per hectare.”7 The chart indicates that sweet potatoes, along with maize, potatoes
and manioc produced higher caloric yields than Old World crops, with sweet potatoes
and maize producing 7.1 and 7.3 million calories per hectare, higher than the “chief Old
World Crops” rice and wheat, which yielded 7.3 and 4.2 million calories per hectare.8 In
support of these findings, historian Andre Gunder-Frank remarks that sweet potatoes,
along with maize, squash and beans” radically increased the cropping possibilities and
chances of survival in Europe and China,” since American crops were better adapted for
growing in harsher climates.9
Sweet potato cultivation, as noted by Gunder-Frank was first undertaken in China
during the 1560’s.10 But how did the sweet potatoes arrive in China? During the Ming
Dynasty, there lived certain Chen Zhenlong- an enigmatic figure. According to Historians
Charles Mann and Christopher Cumo, Chen served as a human agent of the Columbian
Exchange in China. Specifically, Mann points out Chen’s contribution in making China
the “world’s biggest sweet potato grower, producing more than three quarters of the
global harvest.”11 A merchant in the Fujian city of Yuegang,12 he first encountered the
sweet potato during the 1590’s while visiting Manila. A shrewd businessman, Zhen
decided to bribe “the barbarians (probably a reference to the Spanish or the Portuguese)
7
Alfred. W Crosby, The Columbian Exchange: Biological and Cultural Consequencesof 1492
(Westport, CT: Greenwood Publishing Group. Inc, 2003), 175.
8
Ibid.
9
Andre Gunder-Frank, ReOrient:Global Economy in the Asian Age ( United States: University of
California Press,1998), 60.
10
Ibid.
11
Charles Mann, 1493: Uncovering the New World Columbus Created ( Toronto, Canada:
Random House of Canada, 2011), 167-168.
12
Fujian and Yuegang had been China’s “centers of maritime trade”. During the “Age of Sail”,
this meant that both were centers of international trade. Also interesting to note is that Fujian
province was “the worst affected by piracy” and was also chronically at rise of famines.

5. to acquire segments of the vine.” 13 A similar narrative is told by Christopher Cumo, but
differs slightly from Mann’s version with the additional detail that “ the story leaves
unclear how and when the Philippines received the Sweet potato, if Portugal did not plant
it until 1600”.14 Both Mann and Cumo agree that the actual date of introduction of the
sweet potato is unknown, as Fujian merchants kept this information secret.15 However,
Mann suggests that the account of the sweet potato’s introduction into China comes from
a narrative composed by a descendant who wrote the True Account of the Story of
Planting Sweet Potatoes in Qinghai, Henan and Other Provinces an essay detailing how
the crop should be planted. 16 Another interesting hypothesis connects decisions made by
China’s historical bureaucratic leadership positive economic growth in China vis a vis the
cultivation of New World crops.17 According to Angus Madison,
the economic impact of the Chinese bureaucracy was very positive for
agriculture…the bureaucracy promoted the introduction of new world crops such
as maize, potatoes, sweet potatoes, peanuts and tobacco in the Ming.
Did the introduction of the sweet potato yield any tangible outcome? According to
Ruixue Jie, who relates climate change, sweet potatoes and peasant revolts, argues that
prior to the introduction of the crop, “exceptional droughts increased the probability of
peasant revolts by approximately 0.7 percent, while after the arrival of sweet potatoes,
13
Ibid., 168.
14
Christopher Cumo, The Ongoing Columbian Exchange: Stories of Biological and Economic
Transfer(United States of America: ABC Clio, 2015), 293.
15
Mann, 1493, 168. Ibid., 293.
16
Ibid.,
17
Angus Madison, “China in the World Economy: 1300-2030”,International Journal of Business,
Vol 11. No. 3( 2006), 239-254, 240-241. Madison also praises the historical Chinese
bureaucracy by noting that it has helped improve agricultural yields, developed printing, and
settled farmers in new regions. However, he also points out that Chinese bureaucrats considered
agriculture the most significant sector “from which they could squeeze a surplus in the form of
taxes and compulsory levies”.

6. droughts only increased the likelihood of peasant uprisings by 0.2 percent.” 18
Further, it is important to note that since its Chan’s introduction of the crop into
China in the 16th century, one must take into consideration an argument made by
Jennifer Woolfe in her book Sweet Potato: An Untapped Resource. Woolfe describes
China as “ an excellent example of a country which has diversified into many products,
illustrating the versatility of sweet potatoes as a raw material for industrial and food
processing.”19 Historian Jonathan D. Spence would point out that in Modern China, the
sweet potato was a food associated with the peasantry.20 He points out that for farmers in
Shandong Province during the 1930’s, sweet potatoes rather than millet represented an
important crop for the world they lived in.21 Specifically, Spence notes that the poor in
Shandong consumed sweet potatoes at every meal, “every day throughout the year,”and
describes the variety of uses of the sweet potato in local cuisine
From harvest time until the spring of the following year, farmers eat fresh
sweet potatoes; when these are gone, they eat the stored dried slices; these are
boiled, ground into a meal that is mixed with other flour to make bread or
noodles22
Woolfe provides a supplementary account of the sweet potato to Spence’s, and statesthat
the “sweet potato was no doubt an important staple food for most Chinese people until
18
Ruixue Jia, “ Weather Shocks, Sweet Potatoes and Peasant Revolts in Historical China”, The
Economic Journal, Vol. 124, Issue 575 ( 2013), 92-118, 92. Jia also comments that “Weather
shocks” are often considered to increase the likelihood of civil unrest due to associated “negative
income shocks”. However,Jia point out that this connection cannot be decisively confirmed as Jia
lacks “systematic output data for historical China”.
19
Jennfier A. Woolfe, Sweet Potato: An Untapped Resource (Victoria,Australia: Cambridge
University Press,1992), 288.
20
Jonathan D. Spence, The Search forModern China (United States of America: W.W
Norton&Company, 1990), 432. In an interesting contrast with Jia, Spence does not seem to
mention whether peasants revolts were still linked to sweet potatoes,or he might have lacked
records detailing a connection.
21
Ibid.
22
Ibid. Spence suggests that such a monotonous diet was an “indelible part of the rural poor’s
existence.

7. 1949”.23 Specifically, she provides a table indicating “Total Area Devoted to Sweet
Potato Growing in China, 1946-88.” From the table, one can infer that sweet potato
cultivation has been experiencing steady increases since 1946, but these figures decline
gradually from the 1980’s onwards. 24 For example, sweet potato cultivation area
achieved a high of 9.6 million hectares in 1963 – and began to slowly decline in the
1970’s leading to a cultivation of only 6.9 million hectares in 1982, and 6.5 million by
1985.25 Another fact worth noting- earlier, I noted that Spence tells us that for rural
farmers in Shandong province, sweet potatoes served as the basis for a rather
monotonous diet. On that note, Woolfe notes that in Shandong Province sweet potato
production is described as “insufficient but profitable.”26 Yet despite this, the area for
sweet potato cultivation there continues to decline.27
Another New World crop that impacted China in a significant way was American
maize. Much like that of the sweet potato, the exact date when maize was first cultivated
remains unknown.28 Specifically, James McCann notes that although it is unclear when
the crop was first grown, by 1500 AD the Aztec and Mayans civilizations begun calling
the plant descended from a “single unknown ancestor” maize- which meant that which
sustains life.29 McCann also states that maize, like sweet potatoes serve as a major raw
material, as “agribusiness uses its starches for and cellulose for fuel, food, fodder, paint
23
Woolfe, Sweet Potato: An Untapped Food Resource, 488.
24
Ibid.
25
Ibid., Woolfe points out that although sweet potatoes continued to play an important role in
subsistence agriculture, its function began to radically change after the 1970’s as a result of a
government initiative to increase wheat and rice production.
26
Ibid., 492.
27
Ibid.
28
James McCann,“Maize and Grace: History, Corn, and Africa’s New Landscapes,1500-1999”,
Comparative Studies in Society and History,Vol. 43, No. 2(2001), 246-272, 248.
29
Ibid.

8. and penicillin. 30 ” Though McCann suggests that maize evolved from a mysterious
ancestor, Mary Eubanks would argue that scientists have discovered evidence linking
maize to “teosinte”- a “closely related wild grass endemic to Mexico where maize is
believed to have originated.”31 Further, Eubanks exclaims that a great mystery in botany
lies in how teosinte was able to radically transform into a “structure that is unparalleled
anywhere in the plant kingdom, the highly prolific ear that produces hundreds of
kernels.”32
Many theories circulate around when maize was actually introduced into China.
Some historians, such as Joseph Needham provide varying accounts detailing the origins
of maize in China. One suggests that maize had been known in China since
approximately 1570 as “tribute wheat”, “jade wheat”, “jade grain “or “wrapped
grain.’’33 It was also referred as “barbarian wheat” since it came to China from the West,
but other hypotheses postulated that maize arrived in China from India and Burma, yet
other accounts suggest an even earlier date of introduction- 1511- arguing that maize
must have arrived from coastal regions. 34 Still others have cited Spanish historical
documents, stating that “enormous quantities of maize were paid as tax grain in the late
16th century” which might refer to a Spanish origin for Chinese maize. 35 However,
Zheng Yangwen suggests a more concrete origin to maize cultivation in China and notes
30
Mary W. Eubanks, “The Mysterious Origin of Maize”, Economic Botany,Vol.55 No. 4 (2001),
492-514, 494.
31
Ibid.
32
Ibid. Eubanks does note that one possible reason for the mystery of the aforementioned
“radical transformation” is progressive evolution, during which time “mutations accumulated
over a long period”.
33
Joseph Needham, Science and Civilization in China:Volume 5,Chemistry and Chemical
Technology, Part 2, Spagyrical Discovery and Invention: Magisteries of Gold and Immortality
(Cambridge, UK: Cambridge University Press,1984), 455.
34
Ibid.
35
Ibid.

9. that it arrived several decades prior to 1550, prior to yams, which were introduced in
1594.36 Maize was initially introduced into the coastal provinces of Jiangsu, Zhejiang
and Fujian37(interestingly, Fujian was also the site where Zhenlong Chen, the merchant
who introduced sweet potatoes into China, hailed from and is likely also where sweet
potatoes first entered China). Thus when maize was introduced into China, it was
discovered that a major advantage that crop had was that it was capable of growing in
differing climates, specifically “ cold, hot, dry, or wet climates- even on mountains,
valleys or plains.” 38 E.N. Anderson would support this claim and remarks that during
the Ming Dynasty, maize began a massive regional proliferation as the crop “took over
vast stretches of the West and South and began to encroach everywhere.”39 Rebecca
Earle, who suggests that maize, like the sweet potato was a crop more highly valued by
peasants than elites, supports this claim. Specifically, she claims “peasants embraced
these new foods because they required less labor than rice to cultivate.”40 It would seem
that maize was generally a successful crop in urban regions during the 1970’s and
1980’s.41 In fact, maize quickly became a crucial ingredient in many local seasonal
cuisines. In one case( in the city of Shenyang), during the spring 15% of families
36
Yangwen Zhen, China on the Seas: How the Maritime World Shaped Modern China (Leiden,
Netherlands: BRILL,2011), 120.
37
Ibid.
38
Ibid., 124-125. It is interesting to note that while Chinese peasants dedicated the most fertile
lands to cultivating rice, they utilized the sides of mountains and valleys to cultivate maize.
39
E.N. Anderson, The Food of China ( United States of America: Yale University Press,1988),
115. Anderson also relates the presence of maize and the occurrence of rebellions in the South
and South West of China. Specifically, he argues that such a connection exists because the
presence of maize allowed for increases in population.
40 40
Rebecca Earle, “ The Columbian Exchange” in The Oxford Handbook of Food History ed.
Jeffrey M. Pilcher (New York, NY: Oxford University Press,2012), 351.
41 41
Elizabeth J. Leppman, Changing Rice Bowl: Economic Development and Diet in China
(Hong Kong: Hong Kong University Press,2005), 133.

10. claimed that they consumed corn at 5% of their meals,42 while a study conducted in the
fall in Kangping County showed a high incidence of maize consumption where 50% of
families consumed it at 17% of their meals.43 These figures are significant not only
illustrating the significance of the crop in allowing the people of Shenyang and
Kangping County to have a more diversified pallet, but these statistics also provide
evidence supporting the notion that maize was a resilient crop, capable of producing
enough in multiple seasons. In comparing maize to rice, Leppman points out that maize
“requires less water but produces more calories per unit of land.”44
Historically, maize was not only of use to China urban dwellers, for it also had
major impacts on the environment. Specifically, historian Robert B. Marks states
that because general New World crops were available, certain ethnic minorities in
China were able to migrate “throughout the mountainous areas of the south of
China.”45 One such group was the Hakka peoples. Marks notes that in order for the
Hakka to plant maize, they had to cut down “upland forest to open fields.”46 Further,
because maize was a “heavy feeder,” it was able to rapidly decrease the fertility of
upland soils in which it was grown within 2 years.47 In support of this evidence,
Evelyn S. Rawski states that maize supplanted millet as the major “autumn crop” in
some places. Quoting Yen Ju-I, Rawski notes that although mountains harvests in
42
Ibid., 133.
43
Ibid.
44
Ibid., 135.
45
Robert B. Marks, China: Its Environment and History (Lanham,MD: Rowman& Littlefield
Publishers, 2012), 206. Marks also notes that because “hungry crops depleted the soil, soil
naturally returned to a state of infertility, lack of humus, acidity, podsolization or latosolization”.
46
Ibid.
47
Ibid., 214.

11. the fall largely yielded millet, maize yielded more profit.48 Further, Rawski points
out that for those who settled on “marginal lands,” maize became a dominant
staple.49 According to an 18th century gazetteer, who commented on the significance
of the crop to settlers on marginal lands,” what the peasants rely on for food is
barley, buckwheat, millet and primarily, maize.”50 After having several successful
harvests, mountain peasants began relying solely on this crop for food.
In a table provided by Ashtok Gulati, John Dixon, and John Mezies Dixon titled
“ Sown Area and Production of China’s Maize Economy and its Place in the World,
1970-2000”, one can infer that from the 1970’s until the present, the amount of land
dedicated to cultivating maize, along with maize production, has steadily
increased. 51 Specifically, the editors point out that in 1970, maize cultivation
represented 17 percent of China’s arable area, while also making up 16.9 percent of
agricultural production. 52 These figures increase gradually- by the end of the
twentieth century and the beginning of the 21st century, maize cultivation in China
took up between 23 and 27 percent of China’s agriculturally useful land area,
representing approximately 25 to 26 percent of China’s agricultural production.53
Another intriguing statistic is also given- “China’s maize in World Maize
Economy.” By 2000, the area of maize cultivation levels in China was 16.6 percent
of global levels, while Chinese production of the crop represented 18 percent of
48
Evelyn S. Rawski, “Agricultural Development in the Han River Highlands”, Ching-shih wen
t’i, Vol. 3 , No.4 (`1975), 63-81, 68.
49 Ibid.
50 Ibid.
51 Ashok Gulati, John Dixon and John Mezies, eds., Maize in Asia: Changing Marketsand
Incentives( New Delhi,India: Academic Foundation, 2008), 97.
52
Ibid.
53
Ibid.

12. world totals. 54 As of 2010, maize has become China’s “third most important grain,
and China has become the world’s second largest producer of it.”55 Perhaps one the
most significant new uses of maize are in the production of ethanol, in response to
rising oil prices and the search for “cleaner energy sources to combat global
warming.”56 These facts and statistics would no doubt impress the 3rd to 10th
century CE Zapotec and Moche native Americans of Central Mexico, who would
likely marvel at how the crop they once worshipped by “displaying it on ceremonial
ancestral figures in the Zapotec pantheon associated with growing maize”57, has not
only served as a staple crop for the mountain dwelling peasantry of a faraway land
but also as one of that same land’s most important grains.
Ultimately, it can be inferred that though some of the commodities of the
Columbian Exchange have impacted China’s population in profound ways, in none of the
sources I explored did I find a relationship between the cultivation and consumption of
sweet potatoes and maize in 20th century China and China’s population growth, a
hypothesis I had originally intended to formulate. What can be known to historians,
however, are the following: both the sweet potato and maize served as crops that helped
diversify the diets of China’s poor. Though we may never know for sure the exact role of
individual agents of the Columbian Exchange such as the Ming Dynasty Fujian merchant
54
Ibid. Gulati, Dixon and Mezies point out that “currently, maize is grown in every province in
China”, although major differences exist between the types of maize grown and cropping
patterns.” Further, much of China’s maize in grown in the Northeast and Northwest,regions with
a temperate climate.
55 Ibid.
56
Jennifer Huang McBeath, Jerry McBeath, Environmental Change and Food Security in China(
Dordrecht, Heidelberg, London, New York: Springer, 2010), 35. The authors also point out a
controversial fact regarding the 21st century usage of maize in China- specifically, the authors
note that “most corn is used as animal feed”.
57 Eubanks, “Mysterious Origin of Maize”, 493.

13. Chen Zhenlong in introducing the sweet potato into China nor the true means by which
maize first was introduced there, fortunately, tangible, empirical evidence abounds
detailing the impact of these crops on China’s population. As Spence points out , during
the first half of the 20th century, the sweet potato proved to be a reliable staple for the
rural poor in Shandong Province, and experienced a period of rapid increase in
cultivation area, but declined after the after the 1970’s. Even more interesting is the
proposed link between droughts, sweet potatoes and uprisings in China, as Jie remarks
that the introductions of sweet potatoes, “droughts increased the probability of peasant
movements slightly.” 58Evidence suggests that maize impacted China in equally profound
ways-for example, maize allowed urban Chinese resident to enjoy a wider array of foods,
quickly becoming a crucial ingredient in many local cuisines. Kangping County
demonstrated a high incidence of maize consumption where at least half of families there
consumed maize in some form at their meals. Maize however did impact China in more
observable ways as well. When planted by the Shack people in mountainous regions,
maize- what Marks describes as a “heavy feeder”, was capable of causing soils to become
unfertile. 59However in another example, almost ironically, this “heavy feeder” has also
found a new role as a clean source of energy. 60 Thus, the findings that have been
presented are significant in supporting the notion that the Columbian Exchange and its
associated commodities continue to significantly affect regions of the world today-in this
case, one can infer that though sweet potato cultivation rates have likely declined,( as I
have already illustrated), other commodities such as maize continue to be a major
58
Jia, “ Weather Shocks, Sweet Potatoes and Peasant Revolts”,92.
59
Marks, China: Its Environment and History, 214.
60
McBeath and McBeath, Environmental Change and Food Security, 35.

14. agricultural staple in China and may continue to benefit China and the world as an
alternative energy source in years to come.
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