Tropentag 2010 ETH Zurich, September 14 - 16, 2010 Conference on International Research on Food Security, Natural Resource Management and Rural Development
The effects of population and land cover change on food security in Latin America from 1961 2001 Ervina, Daniel, David López-Carrb and Anna López-Carrc a
The University of California, Santa Barbara, 4640 Ellison Hall, Santa Barbara, CA 93106. Email:
[email protected] b
The University of California, Santa Barbara, 4638 Ellison Hall, Santa Barbara, CA 93106. Email:
[email protected] c
Department of Geography, San Diego State University. Email:
[email protected]
Introduction Unprecedented population growth accompanied equally unprecedented land use and land cover changes in Latin America during the second half of the twentieth century, affecting the food security of thousands of agriculturally based communities. The more than doubling of the population of Latin America was accompanied by rural migration to urban areas and extensification, or expansion, of agricultural land at the expense of forest and natural environments (Carr, Lopez, and Bilsborrow 2009). We have previously found that when these processes were examined at a country scale, both Malthusian and Boserupian demographic factors were important in explaining rural out-migration and forest cover decreases (Carr, Lopez, and Bilsborrow 2009). Our results supported Bilsborrow’s application of the theory of multiphasic response: that these two different types of drivers can be simultaneously present, acting influentially at different spatial and demographic levels (Carr, Lopez, and Bilsborrow 2009). The process of agricultural extensification has obvious natural limits, as the remaining high-quality arable land is increasingly exploited in response to growing populations or market demands. In addition, much of the world’s undeveloped arable land is either protected by laws or is of poor soil or topographic quality (World Bank 1995). As extensification becomes more difficult the only viable option for continued increases in food production is agricultural intensification. Of course, the process is not linear and both extensification and intensification occur in areas simultaneously. In addition, a causal relationship between these processes is far from certain, with some
researchers positing that, for example, percentage of forest versus agricultural land is a result of economic development levels (Mather et al., 1999), rather than agricultural necessities. Regardless, for the purpose of this work it will be assumed that agricultural intensification is seen as the answer to increasing agricultural production as viable agricultural land becomes scarcer, or more expensive. Land intensification takes numerous forms, be it existing developed land changing from pasture to cropland, an increase in irrigation, increased use of fertilizers or pesticides, or an increase in active production time by growing multiple crops during one year or not allowing fields to lie fallow. The use of these methods causes environmental problems, including aquifer depletion, the flooding of soil tables, chemical contamination associated with the use of fertilizers and pesticides, and bacterial imbalances in natural water sources from excess nutrients (Carr et al 2006). This final problem is most commonly associated with the ocean dead zones surrounding many developed countries (NASA 2010). The net environmental effects by using less land more intensely is open to debate, but the increase in the byproducts of intensive agricultural practices seems inevitable. The purpose of this paper is to contrast the intensification of agricultural practices and food production in eight countries in Central America and thirteen in South America. This paper is not meant to test this complex and often site-specific relationship but merely to examine the statistics on a broad level to determine any general trends. Methods We use data gathered from the Food and Agriculture Organization of the United Nations’ (FAO) Agricultural Yearbooks, as well as FAO online statistical resources (www.fao.org). The results contain indices measuring kilogram (Kg) of fertilizer use per hectare (Ha), and total number of tractors, which includes all engine-driven agricultural machines like harvesters, threshers, or milkers. These capital-intensive inputs will be contrasted with production yield measures. Yield is expressed as hectogram of crops produced over hectare of cultivated land for two groups of crops: cereals, which include maize and rice, and oil cakes, which includes soybeans and oil palms. We chose these groups because we felt that they contain products that were likely to be cultivated in some significant level throughout the diverse nations of Latin America. Results and Discussion Table 1 contains statistics concerning the use of fertilizer and irrigation in Latin America. It indicates that for all of the nations in Central America fertilizer per hectare of cropland has steadily and dramatically increased since 1961. The least dramatic increase is in Belize where they use a mere 142% more fertilizer per hectare than in 1971, while Honduras uses 2701% more than they did 40 years prior. In most nations this has also been accompanied by an expansion of cropland, leading to a large increase into total fertilizer used (not shown). The results for the South American nations are much the same, with large increases in per hectare use of fertilizer more or less across the board. Table 1 also contains the number of ‘tractors’. The results are similar, if less dramatic, with steady increases in almost all countries.
Table 1 - Agricultural Intensification Measures Fertilizer Use (Kg/Ha. of Cropland) % Change 1961 1971 1981 1991 2001 1961-2001 27.3
64.2
47.5
Tractors (4umber) 1961
1971
1981
1991
2001
% Change 1961-2001 445%
Belize
8.6
22.9
454%
211
596
825
1100
1150
Costa Rica
38.9
115.2 142.2 226.0 239.1
514%
3800
5200
6000
6500
7000
84%
El Salvador
31.8
121.0 116.3 93.6
142%
1600
2642
3320
3420
3430
114%
77.0
Guatemala
9.8
15.9
50.8
80.2
102.7
946%
1950
3250
4020
4220
4300
121%
Honduras
3.8
17.8
16.1
19.3
106.1
2701%
304
1950
3440
4650
5200
1611%
Mexico
8.0
26.4
63.1
61.1
67.8
743%
Nicaragua
A
A
A
A
A
A
Panama
7.2
56000
92800
143078 317313
324890
480%
130
550
2250
2650
2900
2131%
5420
5047
48.0
107.3 52.6
27.8
286%
347
2693
8066
2224%
Central Americaa 8.8 Central Americab 15.5
29.2
61.3
61.0
69.8
696%
64342
109681 168353 344900
356936
455%
52.5
74.7
85.3
95.4
518%
Argentina
0.8
2.9
3.6
6.1
29.7
3464%
120000 171000 213000 274034
299608
Bolivia
0.6
2.4
3.3
3.4
3.6
555%
1300
2300
6000
362%
Brazil
9.5
25.9
51.8
57.4
102.9
982%
72000
183500 569000 730000
806000
1019%
Chile
12.1
30.9
29.0
104.1 223.7
1756%
33550
34050
34370
37570
54000
61%
Colombia
14.3
36.5
53.8
125.2 149.9
949%
18241
23469
29500
31000
21000
15%
Ecuador
4.4
7.2
27.7
27.6
2750%
1558
3400
6844
10919
14680
842% 1995%
124.9
901% 4200
5300
150%
French Guiana
A
A
150.5 108.3 75.0
A
20
39
106
303
419
Guyana
24.0
32.6
28.7
31.0
27.2
13%
3240
3340
3480
3620
3630
12%
Paraguay
6.2
25.6
16.3
11.5
9.1
48%
3900
4900
8035
15878
16500
323%
Peru
0.3
1.6
2.6
5.2
15.7
5024%
6950
11100
11900
12750
13191
90%
Suriname
31.7
63.4
75.0
33.8
60.0
89%
580
940
1120
1300
1330
129%
Uruguay
16.4
61.8
44.6
60.4
82.3
401%
24695
29910
33160
32800
33000
34%
Venezuela
5.5
19.1
41.1
109.8 88.3
1518%
11400
20700
39000
48500
49000
330%
South Americaa South Americab
8.1
19.3
35.2
46.3
82.8
918%
297484 488748 953832 1204101 1318475
10.5
25.8
40.6
52.6
76.3
629%
343% 412%
a Indicates that the bolded region has been treated as a whole. b The mean of the country rows for calculated measures, to avoid unduly large influence by Mexico and Brazil’s on their regions.
Although this country-level data is both broad in area and in to varying degrees estimated or inaccurate, its usage here is meant to outline the general trend of increasing intensification of agricultural land. This intensification should have a relationship with per-area agricultural production, which is displayed in Table 2. The results of these tables show that yield per acre is increasing along with intensification throughout Latin America but at a much lower rate.
Table 2 - Agricultural Production Measures Cereals Yield (Hg/Ha) Year
Oilcakes yield HG/HA
% Change 1961-2001
1961
1971
1981
1991
2001
15290 20714 22761 31012
420%
NA
NA
NA
3612
8354
NA
11535 18378 22763 32989 35496
208%
4546
4305
4685
3591
3490
-23%
16771 16913 16335 19096
104%
6837
7808
6014
4393
6397
-6%
11422 15240 18100 18254
122%
4074
6519
8328
8506
6957
71%
10511 12095 13769 13170 14469
38%
4335
4209
3038
2581
4018
-7%
11049 15299 22925 24269 28556
158%
5206
7207
7836
9077
6761
30%
4172
1961
1971
Belize
5963
Costa Rica El Salvador
9378
Guatemala
8221
Honduras Mexico
1981
1991
2001
% Change 1961-2001
Nicaragua
9397
10826 14712 14171 16928
80%
5121
6430
5623
12728
149%
Panama
9515
11988 16255 18829 18315
92%
99377
103254
85117 3732
2083
-98%
Central Americaa 10702 14850 21704 22839 26795
150%
5249
7129
7526
8238
6624
26%
Central Americab 9446
14009 17911 20078 22766
119%
18499
19962
17234
4958
6349
18%
14106 17835 24249 26661 32068
127%
3624
4247
9408
13237
17694
388% 150%
Argentina Bolivia
9543
11031 13005 13580 17849
87%
4809
5364
9114
14038
12001
Brazil
13463 12908 16110 18506 31485
134%
3426
4029
10208
10693
20864
509%
Chile
14413 19944 21204 40508 49356
242%
5933
9010
6762
11355
16113
172%
Colombia
12752 19045 24797 24507 35483
178%
4850
5921
6195
6483
6778
40%
Ecuador
10106 9619
88%
2354
2457
6103
8096
5690
142%
17679 16739 18994
French Guiana
23877 37142 10784 42722 37870
59%
NA
NA
NA
NA
2920
NA
Guyana
20137 18210 31163 31422 39478
96%
NA
NA
NA
3457
3642
NA
Paraguay
12517 12574 15277 17684 21602
73%
3068
6177
10619
12705
16743
446%
Peru
14877 17501 21349 22926 32413
118%
4708
5385
6178
4803
5782
23%
Suriname
27633 33915 39581 38134 37673
36%
3119
3139
2419
1914
4232
36%
Uruguay
8597
288%
2705
3047
5677
6111
7848
190%
10349 18041 24188 33381
Venezuela
11155 12348 18853 26214 33033
196%
2416
3079
3883
3675
3087
28%
South Americaa South Americab
13466 14985 19404 21446 31450
134%
3572
4177
9824
11520
18749
425%
14860 17879 20930 26445 32360
133%
3728
4714
6961
8779
11218
193%
Conclusions and Outlook Simple arithmetic comparisons of intensification and production figures for each country indicate that there is no linear relationship between agricultural input and output. For example, from 1961 to 2001 Honduras increased its fertilizer use per hectare by 2701 percent and its number of tractors by 1611 percent, yet its gains in yield are low or nonexistent. While other countries have had increases in production along with increases in intensification, the results point to inputs increasing exponentially, while outputs at best increase arithmetically, a familiar and worrisome relationship to those who are familiar with Malthusian theories. This perhaps calls into question the wisdom of Latin America following the agricultural path that the developed nations have taken, and certainly calls for further research into the relationship between intensification and production in Latin America.
References Carr, D.L. A. Barbieri, W. Pan, and H. Iravani, (2006). Agricultural land use and limits to deforestation in Central America. Chapter 6 in Agriculture and Climate Beyond 2015: A new perspective on future land use patterns. Eds. Floor Brouwer and Bruce McCarl. Dordrecht, The Netherlands: Springer. p. 98-107. Carr, D.L., A.C. Lopez, and R.E. Bilsborrow (2009). The population, agriculture, and environment nexus in Latin America: Country-level evidence from the latter half of the 20th century. Population and Environment. 30:222–246. Mather, A.S., C.L. Needle, J. Fairbairn (1999) Environmental Kuznets curves and forest trends. Geography, Vol. 84 (1), pp. 55-65. National Aeronautics and Space Administration (NASA). “Aquatic Dead Zones”. Last modified July 17, 2010. http://earthobservatory.nasa.gov/IOTD/view.php?id=44677.
