The Economics of Desertification, Land Degradation, and Drought

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Figure 5.5—Per capita water storage in selected countries and regions North America Australia Brazil China Thailand Mexico South Africa Ethiopia Source: Grey and Sadoff 2006. Even in areas with well-developed irrigation infrastructure, investment is required to reduce irrigation water loss and improve water use efficiency. This is especially important given the predicted reduction of water due to climate change and the increasing demand for water. Development of Drought-Tolerant Varieties Crop breeding has contributed significantly to the development of drought-resistant varieties. Such development has helped reduce drought-related production risks and increase yield in areas with unreliable rainfall. Moisture Conservation and Water Harvesting These two methods are especially important in semiarid and arid areas. Moisture conservation practices include mulching, incorporating crop residues, planting cover crops, using minimum or zero tillage, and other practices that increase soil carbon. A study in a semiarid site in Kenya showed that mulching increased the length of the growing period from 110 to 113 days (Cooper et al. 2009). In general, mulching and other organic soil-fertility management practices could simultaneously increase crop yield and reduce crop production risks. For example, a study in Uganda showed that soil carbon increased crop yield and reduced yield variance, as shown in Figure 5.6 (Nkonya et al 2011). Figure 5.6—Relationship between soil carbon and crop yield and yield variance, Uganda Source: Nkonya et al 2011. 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 Per capita water storage (m 3 ) 98 . .
Water-harvesting management practices include tie ridges, water basins for trapping rainwater (for example, the zai in west Africa, which was invented by a farmer in semiarid Burkina Faso, is a half-moon planting pit that is filled with crop residues or other forms of plant residues and that traps rainwater and runoff). Income Diversification To build reliable livelihoods, it is important for communities to diversify their livelihoods. This diversification is especially important if the alternative livelihoods do not depend on rainfall. For example, nonfarm activities that do not depend on rainfall will smooth consumption, even in times with drought. Development of Weather Forecasting and Climate Change Information It is important for farmers to learn about this information so they know what to do and when. Summary This section gave an overview of the measures that are suitable to addressing the various types of land degradation. Water-induced soil erosion can be controlled on crop fields by mechanical methods (such as SWC structures), agronomic methods (such as mulching, planning patterns), and soil management techniques (such as zero tillage, minimum tillage). Establishing windbreaks and using planting techniques that make soil surfaces less vulnerable are common ways to reduce the impacts of wind-induced soil erosion. Soil nutrient depletion results from poor land management and leads to more outflow of nutrients than inflow. Soil salinity is a major problem in irrigated areas, with hot spots in Central Asia and Australia. A major management tool against salinity is the appropriate management of water tables. Measures to avoid or mitigate soil compaction and its impacts include improved drainage systems, salt-tolerant crop varieties, and remediation through leaching. A study by Pender (2009) showed that less than 3 percent of total cropland in Sub-Saharan Africa is under sustainable land and water management practices. Recent studies have shown that integrated soil fertility management (judicious manipulation of nutrient stocks and flows from inorganic and organic sources) is more beneficial to the soil than is the application of fertilizer or organic matter. Soil compaction may reduce yields quite tremendously—for example, by 38 percent in Pakistan (Ishaq et al. 2001). Whereas compaction due to livestock pressure is a problem in the Sahel, the horn of Africa, Central Asia, northeastern Australia, Pakistan, and Afghanistan, compaction due to heavy machinery occurs predominantly in the United States, Europe, South America, India and China. Practices to address compaction include periodic deep plowing, controlled traffic, conservation tillage, and crops with deep-tap root systems. The loss of biodiversity was assessed in the TEEB (2010) reports, which predicted a strong reduction in biodiversity (measured as mean species abundance) by 2050. Afforestation, reforestation, protection programs, diversified cropping, and livestock systems are all suitable methods to reduce the species loss. Overgrazing is a problem in the arid and semiarid rangelands. Transhumant livelihood is a sustainable way of using rangelands that has been threatened by expanding agricultural areas; thus, campaigns to protect transhumant pastoralists have been launched. This efforts need to be accompanied by strong local institutions that help manage rangelands sustainably. Involving rangelands in the carbon market is another strategy to improve rangelands. To mitigate the impacts of droughts, investments in irrigation and water storage, as well as measures for moisture conservation (for example, mulching, incorporation of crop residues) and water harvesting (for example, tie ridges, water basins), will help reduce drought-related risks to people. Developing drought-tolerant crops is another way to decrease vulnerability to droughts. In addition, income diversification is important for building reliable, less-vulnerable livelihoods. Development of weather forecasting and easy access to information would also allow farmers to prepare themselves better. 99
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IFPRI Discussion Paper 01086 May 20
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Contents Abstract vii Acknowledgmen
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List of Figures 1.1—Conceptual fr
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ABSTRACT Attention to land degradat
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ABBREVIATIONS AND ACRONYMS ADB Asia
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SCAR Soil Conservation in Agricultu
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In the present report, the conceptu
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Framework: Confronting Action versu
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understand these arrangements in or
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Figure 1.3—Prevention, mitigation
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on assessments at the micro level (
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does not clearly distinguish betwee
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Figure 2.1—GLASOD (1991) global a
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International Earth Science Informa
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Box 2.1—Continued Normalized Diff
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Figure 2.4—Loss of annual NPP, GL
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Figure 2.7—Annual loss of NPP in
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Table 2.2—Nitrogen application ra
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Figure 2.12—Areas affected by hum
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output—which is a selection of su
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GLADIS also underlines the linkage
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Box 2.2—Continued A map on global
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Table 2.3—Global land degradation
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Table 2.3—Continued Project and d
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Table 2.4—Continued Location 10 2
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Table 2.6—Extent and severity of
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National Level Policies As discusse
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Such support has also been directed
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Migration, either as outmigration o
Page 60 and 61: The preceding discussion shows the
Page 62 and 63: Results Correlation Analysis Consis
Page 64 and 65: Figure 2.23—Relationship between
Page 66 and 67: Effects of Land Degradation On-Site
Page 68 and 69: soils and higher land productivity.
Page 70 and 71: Acknowledging the work of GLADIS, a
Page 72 and 73: health, education, security, enviro
Page 74 and 75: Box 3.1—Recent major economic ass
Page 76 and 77: An appropriate economic tool for a
Page 78 and 79: Figure 3.4—Cost of action and cos
Page 80 and 81: enefit—for example, income. This
Page 82 and 83: Figure 3.6—Ecosystem services fra
Page 84 and 85: Replacement Cost Approaches The rep
Page 86 and 87: Box 3.2—Measuring land degradatio
Page 88 and 89: land degradation and conservation m
Page 90 and 91: Flooding and Aquifer Recharge Richa
Page 92 and 93: year (Diao and Sarpong 2007). Sonne
Page 94 and 95: Bringing together the different cos
Page 96 and 97: This section discusses the most imp
Page 98 and 99: governing land use patterns (Leeman
Page 100 and 101: promotion of community forest manag
Page 102 and 103: Box 4.3—Reducing emissions from d
Page 104 and 105: Soil Nutrient Depletion Soil nutrie
Page 106 and 107: that the yields of salt-tolerant wh
Page 108 and 109: Figure 5.3—Forest area as a perce
Page 112 and 113: Introduction 6. CASE STUDIES Five c
Page 114 and 115: Salinity The effects of salinity on
Page 116 and 117: Third, to correctly decide which ac
Page 118 and 119: Costs of Action and Inaction We eva
Page 120 and 121: The NGOs and religious organization
Page 122 and 123: have a strong influence on NRM (And
Page 124 and 125: We estimated the cost of action (de
Page 126 and 127: Figure 6.15—Costs of action and i
Page 128 and 129: Of interest to us is the strategy t
Page 130 and 131: 7. PARTNERSHIP CONCEPT The review o
Page 132 and 133: degradation. All this should be don
Page 134 and 135: Finally, the global assessment of D
Page 136 and 137: the experience of and lessons learn
Page 138 and 139: Table 7.3—Example of E-DLDD resea
Page 140 and 141: 8. CONCLUSIONS Since the publicatio
Page 142 and 143: lowest in the region. From a socioe
Page 144 and 145: Table A.1—Land degradation assess
Page 146 and 147: Table A.2—Continued Author Region
Page 148 and 149: Table A.3—Continued Author Countr
Page 156 and 157: Table A.5—Costs of land degradati
Page 158 and 159: Figure B.1—Land use systems of th
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REFERENCES Abelson, P. 1979. Cost B
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Benin S., E. Nkonya, G. Okecho, J.
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Clark, E. H. 1985. The Off-Site Cos
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De Jager a., D. Onduru and C. Walag
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Foster, V., and C. Briceño-Garmend
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Holden, S. and H. Lofgren. 2005. As
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Lapar, M. L., and S. Pandey. 1999.
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Nachtergaele, F., M. Petri, R. Bian
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Pender, J. L. 2009. “Food Crisis
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Sauer, J., and H. Tchale. 2006. Alt
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Tan, Z. X., R. Lal, and K. D. Wiebe
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———. 2010. “Assessment of L
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RECENT IFPRI DISCUSSION PAPERS For
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The Economics of Desertification, Land Degradation, and Drought

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