Dataset

EPAR Research Brief #225
Publication Date: 10/15/2013
Type: Literature Review
Abstract

After cereals, root and tuber crops - including sweetpotato and yam (in addition to cassava and aroids), are the second most cultivated crops in tropical countries. This literature review examines the environmental constraints to, and impacts of, sweetpotato and yam production systems in Sub-Saharan Africa (SSA) and South Asia (SA). The review highlights crop-environment interactions at three stages of the sweetpotato/yam value chain: pre-production (e.g., land clearing), production (e.g., soil, water, and input use), and post-production (e.g., waste disposal, crop storage and transport). We find that sweetpotato and yam face similar environmental stressors. In particular, because sweetpotato and yam are vegetatively propagated, the most significant (and avoidable) environmental constraints to crop yields include disease and pest infection transmitted through the use of contaminated planting materials. Published estimates suggest yield gains in the range of 30–60% can be obtained through using healthy planting material. Moreover, reducing pest damage in the field can greatly increase the storage life of root and tuber crops after harvest – currently losses from rot and desiccation can claim up to 100% of stored sweetpotato and yam on smallholder farms.

EPAR Research Brief #215
Publication Date: 08/31/2013
Type: Literature Review
Abstract

Maize has expanded through the 20th and into the 21st century to become the principle staple food crop produced and consumed by smallholder farm households in Sub-Saharan Africa (SSA), and maize production has also expanded in South Asia (SA) farming systems. In this brief we examine the environmental constraints to, and impacts of, smallholder maize production systems in SSA and SA, noting where findings apply to only one of these regions. We highlight crop-environment interactions at three stages of the maize value chain: pre-production (e.g., land clearing), production (e.g., fertilizer, water, and other input use), and post-production (e.g., waste disposal and crop storage). At each stage we emphasize environmental constraints on maize production (such as poor soil quality, water scarcity, or crop pests) and also environmental impacts of maize production (such as soil erosion, water depletion, or chemical contamination). We then highlight best or good practices for overcoming environmental constraints and minimizing environmental impacts in smallholder maize production systems. Evidence on environmental constraints and impacts in smallholder maize production is uneven. Many environmental concerns such as biodiversity loss are commonly demonstrated more broadly for the agroecology or farming systems in which maize is grown, rather than specifically for the maize crop. And more research is available on the environmental impacts of agrochemical-based intensive cereal farming in Asia (where high-input maize is a common component) than on the low-input subsistence-scale maize cultivation more typical of SSA. Decisive constraint and impact estimates are further complicated by the fact that many crop-environment interactions in maize and other crops are a matter of both cause and effect (e.g., poor soils decrease maize yields, while repeated maize harvests degrade soils). Fully understanding maize-environment interactions thus requires recognizing instances where shortterm adaptations to environmental constraints might be exacerbating other medium- or long-term environmental problems. Conclusions on the strength of published findings on crop-environment interactions in maize systems further depend on one’s weighting of economic versus ecological perspectives, physical science versus social science, academic versus grey literature, and quantity versus quality of methods and findings.

EPAR Research Brief #213
Publication Date: 08/31/2013
Type: Literature Review
Abstract

 In this brief we examine the environmental constraints to, and impacts of, smallholder sorghum and millet production systems in Sub-Saharan Africa (SSA) and South Asia (SA). Millet in this paper primarily refers to pearl millet (Pennisetum glaucum), although a number of other millets of significance to smallholder production and food security are also discussed. Sorghum and millets are known for being more tolerant of major environmental stresses including drought and poor soil quality than other major cereals. But water availability is still among the greatest constraints to increased grain production, and soil fertility also significantly limits yields, especially in cases where cultivation occurs on marginal lands and where crop residues are removed for alternative uses. Ultimately sorghum and millets’ relatively higher tolerance to abiotic stresses is expected to promote an increase in global cropping area for sorghum and millets as an adaptation to climate change. Sorghum and millet exhibit relatively few of the environmental impacts commonly associated with more intensively cultivated crops such as fertilizer runoff, pesticide contamination, or water depletion, since both of these crops are overwhelmingly grown by smallholder farmers with few, if any, chemical or irrigation inputs. Nevertheless, the tendency to grow sorghum and millet on marginal and heavily sloped lands does pose some environmental risks – including soil degradation and erosion – that can be mitigated through the adoption of best practices as described in the brief. 

EPAR Research Brief #208
Publication Date: 05/01/2013
Type: Literature Review
Abstract

Rice is the most important food crop of the developing world and is grown on over 155 million ha worldwide. Food security of the poor, especially in Asia, depends critically on rice availability at an affordable price. In this brief we examine the environmental constraints to, and impacts of, smallholder rice production systems in South Asia (SA) and Sub-Saharan Africa (SSA), noting where the analysis applies to only one of these regions. We highlight crop-environment interactions at three stages of the rice value chain: pre-production (e.g., land clearing), production (e.g., water and other input use), and post-production (e.g., waste disposal). At each stage we emphasize environmental constraints on production (e.g., poor soil quality, water scarcity, crop pests) and also environmental impacts of crop production (e.g., soil erosion, water depletion, pest resistance). We then highlight best or good practices for minimizing negative environmental impacts in smallholder rice production systems. Evidence on environmental issues in smallholder rice production is uneven. Far more research is available for Asian rice production systems, as compared to African rice systems. And with the possible exception of the evidence on water limits to increasing productivity, conclusions on the strength of published findings on crop-environment interactions in rice depends on one’s weighting of economic versus ecological perspectives, physical science versus social science, academic versus grey literature, and quantity versus quality of methods and findings.

EPAR Research Brief #212
Publication Date: 03/05/2013
Type: Literature Review
Abstract

This literature review examines the environmental constraints to, and impacts of, wheat production systems in South Asia (SA) and Sub-Saharan Africa (SSA). The review highlights crop-environment interactions at three stages of the wheat value chain: pre-production (e.g., land availability), production (e.g., heat, water, and soil), and post-production (e.g. storage, crop residues, and transport). At each stage we emphasize environmental constraints on production (e.g., poor soil quality, water scarcity, crop pests, etc.) and also environmental impacts of crop production (e.g., soil degradation, water depletion and pollution, greenhouse gas emissions, etc.). We then highlight published best practices for overcoming environmental constraints and minimizing environmental impacts in wheat production systems. We find that wheat is a significant crop that will need to increase production to meet increasing demand. Most land suitable for wheat production is already under cultivation. Improved production methods are needed to address the demand and avert environmental impacts of producing wheat.  It should not be assumed that improved varieties alone will be able to realistically address growing demands for wheat. Improved variety seeds should be combined with best practices of improved crop management techniques: optimal planting time, zero tillage, fertilizer management, intercropping, crop residue incorporation, and improved storage techniques.

EPAR Research Brief #50
Publication Date: 12/29/2009
Type: Research Brief
Abstract

EPAR’s Political Economy of Fertilizer Policy series provides a history of government intervention in the fertilizer markets of eight Sub-Saharan African countries: Côte d’Ivoire, Ghana, Kenya, Malawi, Mozambique, Nigeria, Senegal, and Tanzania. The briefs focus on details of present and past voucher programs, input subsidies, tariffs in the fertilizer sector, and the political context of these policies. The briefs illustrate these policies’ effect on key domestic crops and focus on the strengths and weaknesses of current market structure. Fertilizer policy in SSA has been extremely dynamic over the last fifty years, swinging from enormous levels of intervention in the 1960s and 70s to liberalization of markets of the 1980s and 1990s. More recently, intervention has become more moderate, focusing on “market smart” subsidies and support. This executive summary highlights key findings and common themes from the series.

EPAR Research Brief #78
Publication Date: 11/06/2009
Type: Literature Review
Abstract

In the decades following independence in 1960, Côte d’Ivoire stood out as a shining example of economic growth in Sub-Saharan Africa. GDP increased at an annual average of 8.1 percent from 1960 to 1979, led largely by cocoa and coffee exports.  Low export earnings from a fall in world cocoa prices and a heavy public debt burden halted this growth in the 1980s, followed by civil conflict beginning in 1999. Three decades of focus on export crops rather than food crops also left Côte d’Ivoire with a growing food deficit. This literature review examines the state of agriculture in Côte d’Ivoire and the history of government involvement in the agricultural sector. We find that while the country is poised to reemerge from a decade of economic stagnation and civil war after signing the Ouagadougou Political Accord in 2007, the political economy of Côte d’Ivoire is still heavily dependent upon and influenced by the production of cocoa. Cocoa is the top export, and cocoa export taxes provide one of the largest sources of revenue for the Government of Côte d’Ivoire (GoCI). Cocoa is not heavily dependent on fertilizer inputs and growers have increased production by expanding cropland. The small contribution of fertilizer to the production of this essential crop may help explain the GoCI’s low priority on expanding fertilizer production and use. Given that a large part of government revenue comes from the export of cocoa and coffee, the government has chosen to focus resources on crops that increase revenue. Even with the food riots in 2008, the GoCI has not made increasing domestic food production an important focus of agricultural policy.

EPAR Research Brief #77
Publication Date: 11/03/2009
Type: Literature Review
Abstract

Agriculture is the most important sector in the Ghanaian economy. In 2008, it accounted for over 32 percent of GDP and employed over half of the labor force. Economic development in Ghana has historically been dependent on the success of agriculture, particularly the main export crop, cocoa. Despite the sector’s importance, Ghanaian farmers have one of the lowest fertilizer application rates in Sub-Saharan Africa. The combination of a dominant agricultural sector, nutrient-poor soils, low fertilizer use among smallholder farmers, and the absence of locally produced inorganic fertilizers has prompted the government of Ghana (GoG) to intervene in the fertilizer market. This literature review examines the state of agriculture in Ghana, the history of the fertilizer market, and the current market structure. We find that the GoG has been a major actor in the inorganic fertilizer market over the past 50 years, from exercising total control of the domestic supply chain in the 1960s and 1970s to more indirect interventions in later years. In recent years, agricultural growth has averaged 5.5 percent as compared to 5.2 percent growth in the rest of the economy.  However, most of this growth has been due to land expansion and favorable weather conditions rather than increased productivity.  Increased fertilizer use among smallholder farmers has the potential to contribute to future agricultural growth and continued economic success.

EPAR Research Brief #80
Publication Date: 10/19/2009
Type: Literature Review
Abstract

Governments in Sub-Saharan Africa have often intervened in the fertilizer sector to promote more optimal levels of fertilizer use. Many West African nations, in particular, have inherited a legacy of government involvement, stemming from French colonial policies that encouraged state participation in the agricultural sector. Senegal's colonial past has influenced much of its present economy, from its principal export crop (peanuts) to its major food import (rice). The colonial legacy includes a relatively high degree of urbanization; limited domestic industrial capacity; institutions, policies, and agricultural networks focused on supporting a single export crop; and a history of state intervention into markets. After government intervention in the 1960s and 1970s, followed by a period of liberalization in the 1980s and 1990s, Senegal is again defining its agricultural policy. This literature review examines the state of agriculture in Senegal and the history of Senegalese agricultural policy in order to understand past and current trends in fertilizer usage. We find that Senegal continues to experience a high level of food price fluctuations as it imports increasing amounts of rice to cover its food deficit. Increased use of fertilizer, along with irrigation technology may help improve rice production and increase food security. To achieve this goal, the Government of Senegal (GoS) has embarked on several initiatives, notably the Agro-Silvo-Pastoral Law (LOASP) and the Grande Offensive Agricole pour la Nourriture et l’Abondance (GOANA), employing subsidies to increase fertilizer demand and making food sovereignty a national priority. In the coming years, GoS will need to determine what role the government should play in the agricultural sector, and what level of intervention can be sustained in the long-term.

EPAR Research Brief #42
Publication Date: 07/31/2009
Type: Research Brief
Abstract

Nigeria’s experience with fertilizer subsidy programs has been different than that of other countries in Sub-Saharan Africa. Nigeria is one of the only African countries capable of producing fertilizer domestically. But Nigeria is also large and densely populated. This makes national agricultural policy difficult due to logistical problems with implementation and the unique fertilizer needs of the various agro-ecological zones. This research brief discusses the effects of Nigeria’s input subsidy programs on maize production and fertilizer consumption. It focuses on the years 2000 to 2007, but also includes a discussion of Nigeria’s subsidy history from the early 1970s to 2009. Researchers have had difficulty studying Nigeria’s subsidy schemes due to a lack of data. In spite of decades of authoritarian, centralized leadership, Nigeria’s states have significant power to implement their own subsidies. This complicates any evaluation of a program’s effectiveness, in part due to the variety of subsidies at any given time, as well as inconsistent accounting practices.