Sustainable water management in African agriculture

By Katrin Glatzel

Credit: Katrin Glatzel, 2015 (Senegal)

In sub-Saharan Africa (SSA) where agriculture is predominantly rainfed, farmers’ access to water is often limited based on seasonal variation. Yet water scarcity in the region is not necessarily caused by a physical lack of water, but rather by an ‘economic water scarcity’. This implies that the necessary public investments in water resources and infrastructure are not substantial enough to meet water demands in an area where people do not have the means to make use of water sources on their own. In fact, in many parts of SSA there is plenty of water available. However, groundwater resources, such as aquifers, remain a relatively abundant yet underused resource, with less than 5% of the water used for irrigation coming from groundwater.

The challenge is therefore to increase the amount of available water that is ‘harvested’ for crop growth. Such water harvesting can be done at the field, farm or watershed level. In some places, there is a potential for groundwater extraction using boreholes. And research by the International Food Policy Research Institute (IFPRI) has shown that motor pumps have the potential to expand the amount of agricultural land irrigated during the dry season to 30 million hectares — four times the current area. There is urgent need to sustainably increase the amount of irrigation from the current 6% of arable land. Until then an estimated 200 million people in SSA – that is 18% of the continent’s population – face serious water shortages.

Furthermore, climate change and a growing population continue to pose additional challenges to water management in agriculture. Prolonged periods of drought in many parts of SSA are becoming increasingly frequent. This increases pressures on valuable water resources and agricultural irrigation. In response, water conservation policies, strategies, and activities such as water harvesting, are ever more important to manage and protect fresh water as a sustainable resource to meet current and future human demands.

The Sustainable Intensification of Aquaculture

Two new reports out this week urge greater integration of fish in achieving food and nutrition security and sustainable food systems.

The World Resources Institute in their fifth instalment of the soon to be released World Resources Report, partnered with WorldFish, the World Bank, INRA, and Kasetsart University to explore how aquaculture can grow sustainably, reducing its environmental impact and contributing to food and nutrition security.

Aquaculture is a rapidly growing industry and production between 2000 and 2012 more than doubled. Aquaculture output is growing at 6.6%  per cent per annum worldwide. As wild catch fish stocks decline, peaking in the 1990s, aquaculture becomes ever more important for meeting demands for fish, which contribute one sixth of animal protein consumed across the globe. To meet future demand it’s estimated that aquaculture production will have to increase by over 100% by 2050.

Aquaculture has been linked with some serious environmental concerns particularly for high-input high-output intensive systems – the eutrophication of lakes and transformation of species assemblages on the seabed as a result of nutrient enrichment; the physical degradation and clearing of coastal habitats such as mangroves for shrimp aquaculture; the introduction of non-native species to natural ecosystems; and the salinisation of drinking water resources, for example. Already large-scale improvements to the aquaculture sector are taking place: increasing resource-use efficiency, mangrove conversion is largely being prevented and the share of fishmeal and fish oil in feeds is declining, putting less pressure on wild fish resources.

Without appropriate management of these systems, however, the intensification of aquaculture, as wild fish stocks decline and demand for fish increases, could also intensify these environmental impacts. Sustainable intensification is called for, in the case of aquaculture defined as: advancing socio-economic development; providing safe, nutritious food; increasing the production of fish relative to the amount of land, water, feed, and energy used; and minimising water pollution, fish diseases, and escapes. The WRI paper explores various scenarios of aquaculture growth to 2050 to investigate whether the sector’s development can be sustainable. They find that under most scenarios environmental impacts, such as greenhouse gas emissions, are increased. The report recommends five approaches to transforming the aquaculture sector, increasing production while reducing its impacts:

2014 Africa Progress Report

Released today, the 2014 Africa Progress Report, Grain, fish, money. Financing Africa’s green and blue revolutions, discusses agriculture, fisheries and finance, outlining reasons for optimism but also some of the priorities and barriers to Africa’s development.

The Africa Progress Panel (APP), chaired by Kofi Annan, former Secretary-General of the United Nations and Nobel laureate, consists of ten individuals across the public and private sectors who advocate for equitable and sustainable development for Africa. The annual Africa Progress Report, published every year in May, utilises the best research and analysis available on Africa to make viable, policy recommendations for African policy makers, international partners and civil society organisations.

Many African countries have seen significant economic development and transformation in the last few decades and incomes are set to double in the next 22 years. Senegal, for example, has gone from a debt crisis to selling sovereign debt on eurobond markets in ten years. But this economic growth is slow to trickle down to the many rural-dwelling Africans whose livelihoods are still precarious. In west Senegal, ongoing illegal, unreported and unregulated fishing by commercial fleets from other countries has left fish stocks dwindling, affecting tens of thousands of artisanal fishermen. As the report states this is just one example of the growing divide between the few who can benefit from Africa’s rising economic prosperity and the large number of people chronically poor and hungry.

On the one hand, the report states, the political and economic landscape of Africa is changing: exports and foreign investment are increasing while dependence on aid is declining. Democracy, transparency and accountability are entering into the language of policymakers more and more. But poverty and hunger are still enormous challenges and progress in making economic growth both wide-ranging and sustainable has, so far, fallen short. For Africa, as the report states, “the time has come to set a course towards more inclusive growth and fairer societies.”

In order to translate some of the economic growth to improving people’s wellbeing and livelihoods, Africa’s policymakers must focus on developing the continents farming and fishing industries, those economic sectors employing and supporting the majority of the Africa population. Smallholder farmers receive relatively little support from the government. As the report states, “Agriculture remains the Achilles’ heel of Africa’s development success story.” Subject to conflicting and sometimes damaging development initiatives, African farmers have some of the lowest levels of access to productive resources, markets and technologies in the world. As such agricultural productivity is very low. As has been seen in many developed and emerging economies an agricultural revolution is essential to overall growth and poverty eradication. Africa, as the report goes on to say, needs its own Green Revolution, one designed for the African continent. In particular increasing access to technologies such as drought-resistant varieties and tackling policy and market failures, which prevent farmers from increasing their productivity and incomes.

World Water Day 2014

By 2025 1.8 billion people will be living in regions of absolute water scarcity. Global water use grew at more than twice the rate of human population increase in the last century. Of the world’s population without access to clean and safe water, 37% live in sub-Saharan Africa. These are just some of the shocking statistics that highlight the urgent need to ensure access to clean and safe water for people across the world.

Tomorrow is World Water Day 2014, a day that aims to increase global recognition of the water resource scarcity challenges we face. It seems that more and more we are hearing reports of water scarcity leading to transboundary conflict, particularly in regions that may already be politically unstable. For example, in 2006, Israel bombed irrigation canals that supplied water from the Litani River to 10,000 acres of farmland in Lebanon. And these conflicts are not new, the fight over the water of the Jordan River was one of the causes of the 1967 Six-Day War between Israel and Egypt, Iraq, Jordan and Syria. In a 2012 report from the U.S. National Intelligence Council entitled, “Intelligence Community Assessment on Global Water Security,” North Africa, the Middle East and South Asia were identified as regions that are likely to face serious challenges managing water resources.

Water stresses have also led to cooperation though, and much more often than they have led to conflict. How this will change as water scarcity intensifies is unknown. Something like 3,600 agreements and treaties on water have been signed to date including the establishment of the 1957 Mekong River Commission between Cambodia, Laos, Thailand and Vietnam, an ongoing partnership held up as being successful. The UNESCO–Green Cross International project entitled “From Potential Conflict to Cooperation Potential” (PCCP), launched in 2006 aims to help parties negotiate and prevent conflict over water.

In their 2006 International Herald Tribune article, “A global problem: How to avoid war over water“, Watkins and Berntell suggest a four-part solution based on:

1) Improving domestic water policies that support efficiency and conservation;

2) Negotiating with other nearby countries when planning such things as river alterations and shared groundwater usage;

3) Establishing intergovernmental river-basin institutions; and

4) Bringing together political leaders and technical experts to find solutions and promote cooperation.

Of course it isn’t just water scarcity that can pose a threat to national and international security. Conflict over energy is just as evident, if not more so in the media, and this year’s World Water Day has a theme of “Water and Energy”. The UN launched their World Water Development Report today. Key messages for this year’s report on water and energy include:

• Water requires energy and energy requires water
• Supplies of both are limited and demand is increasing
• Saving energy is saving water. Saving water is saving energy
• The “bottom billion” urgently needs access to both water and sanitation services, and electricity
• Improving water and energy efficiency is imperative as are coordinated, coherent and concerted policies

World water day celebrations are taking place in Tokyo today and tomorrow. Information resources on water and energy can be found here.

Scaling Up Sustainable Land and Water Management Practices

Land degradation and declining soil fertility are major threats to agricultural productivity and food production, particularly in the drylands of sub-Saharan Africa, where land management practices, high fertiliser prices and water shortages contribute and exacerbate the problems. The World Resources Institute have previously calculated that to eradicate food insecurity we need to produce 69% more calories between 2006 and 2050, while at the same time protecting the world’s water, climate and ecosystems. A new report by the WRI entitled Improving Land and Water Management, instalment four of their Creating a Sustainable Food Future series, outlines some of the land and water management practices that can mitigate land degradation and increase agricultural output. They highlight four practices that are particularly promising, which along with raising yields and productivity can increase incomes, natural capital and resilience to climate change. These are:

Agroforestry – the integration of trees and shrubs onto farms

Conservation agriculture – the combination of reduced or no tillage, crop rotations and on-farm conservation of crop residues or cover crops

Rainwater harvesting – the use of on-farm systems such as bunds, pits and trenches, to collect rainfall and prevent water loss from soils

Integrated soil fertility management – the incorporation of prudent and targeted use of fertiliser with organic alternatives such as manure, compost, leaf litter, crop residues and phosphate rock

The report provides evidence of the impacts these farming practices can have, for example, the combination of conservation agriculture and crop rotations has resulted in 50% higher yields of maize in Zambia. These practices can be combined with each other as well as with more conventional technologies e.g. microdosing of fertilisers.

Implementing and combining these four techniques at scale will require much coordination between different users of the landscape, warranting an integrated landscape approach that acknowledges and plans for multiple land uses. Adoption of these practices is currently low and the main barriers to successful scaling include poor knowledge dissemination, weak land tenure systems and poor coverage of extension services. The potential of these improved land and water management practices has been calculated: if implemented on some 75 million hectares of cropland, with an expected increase in yields of 50%, farmers would produce 22 million tons more food each year, equating to an extra 615 kilocalories per person per day for 285 million people living in Africa’s drylands.

Agroecosystems: the future of sustainable farming

A new book launched last month at World Water Week in Stockholm sets out the challenges the world faces in feeding a growing population in the face of severe resource constraints and climate change. Authors of the book, the CGIAR Research Program on Water, Land and Ecosystems in partnership with the United Nations Environment Program (UNEP), emphasise the importance of adopting a new way of farming, viewing farms as interfaces between achieving global food security and environmental protection or in other words as agroecosystems.

With a focus on water, the book details the importance of ecosystem services for the direct provision of food and as the ecological foundation upon which agriculture rests. In a recent UK government report ecosystem services were estimated to benefit the UK economy by as much as £1.6 billion per year with pollinators contributing some 13% of the country’s annual income from farming. Not only are these services under threat from farming systems that degrade the resource base but from such global hazards as climate and demographic change.

The book, Managing Water and Agroecosystems for Food Security, not only details the challenges we face in providing enough food to feed the population and the importance of water for agriculture and a range of other ecosystem services, it also provides practical approaches to managing water for agroecosystems. For example, increasing water productivity across a range of food producing industries as well as market mechanisms such as Payments for Ecosystems Services. As the authors acknowledge, however, an agroecosystems approach will require societal and political change at the local, landscape and global levels.

A Paradigm Shift for Agriculture: The Case for SRI

Perhaps the greatest change in mindset in human history was from the belief in a Ptolemaic or geocentric view of the universe (Earth at the orbital centre of all celestial bodies) to a Copernican or heliocentric (the sun at the centre).

Today the world is facing many threats not least the need to feed an ever increasing population amid severe resource constraints. World food production per capita peaked in 1984 and if we are to achieve global food security we require, according to Norman Uphoff, political scientist at Cornell University and lead of the SRI-Rice group, a similar paradigm shift.

Presenting his case for the use and adoption of Systems of Rice Intensification at the International Institute for Environment and Development on 4th July, Uphoff explained the dire need for a change in mindset in agriculture: from an egocentric view, placing humans as the producers of food and manipulators of nature, to a heliocentric, whereby humans capitalise on the power and resources of natural systems while accepting their role within the system rather than outside. So often we view food production systems as closed, whereby inputs and outputs are measurable, linear and proportional but in doing so we neglect the biology of these systems. We fail to understand the myriad of ecological relationships that combine to create the food on our plate.

For decades the Green Revolution has allowed food production to keep pace with population growth, based on two pillars:

1) The improvement of genetic potentials of crop and animal genotypes; and

2) Greater application of external inputs.

But today we are seeing declining returns to this form of farming. In China where the application of 1kg of nitrogen fertiliser to crops would result in a 20kg increase in rice yields we are now seeing an increase of only 1 to 5kg. Despite this failing to maintain the momentum of past productivity trajectories, Uphoff explains that many agronomists are still arguing for current farming methods, only slightly improved. He believes we need a greater focus on the ecological sciences. In particular the contributions of plant roots and soil biota to crop health, and research into how to get more productive phenotypes from existing genotypes through making beneficial changes in crop environments. And SRI does just that. What’s proven to be a rather controversial method of farming rice and other crops, and seemingly dismissed by many research institutions, has yielded impressive results.

Four ways to reduce water use in agriculture

Today is World Water Day 2013, celebrating the International Year of water cooperation. A paradigm of the world’s water challenges is that although agriculture accounts for approximately 70% of global water resources, around one billion people are chronically hungry.

As water for irrigation and food production constitutes one of the greatest threats to the sustainability of the world’s freshwater resources, we discuss four methods of reducing water use in agriculture, methods that can reduce water use without limiting, and sometimes increasing, food production.

Grow crops that use less water. This can mean either crops that due to their physiology require less water. For example growing grapes and olives requires significantly less water than tomatoes or bananas. Or it can mean crops bred to require less water such as the Water Efficient Maize for Africa (WEMA) project.  Of course the choice of crops grown is also dependent on environmental and socio-economic conditions.

Precision use of irrigation either by scheduling irrigation for times when the crops needs it or using irrigation only in areas needed. Methods can include direct measurement of soil water content to inform on timing and placement, sprinkler or drip irrigation. But issues of access to and management of water supplies can limit the feasibility of some of these techniques in some areas.

Use methods alternative to irrigation such as rainwater harvesting and treated wastewater.

Enhance water retention in the soil through farming methods and systems such as residue management, conservation tillage, zai, bunds, contouring and field levelling. This will reduce the amount of water that needs to be applied to the field.

For the future new technologies such as micro-scale solar desalination units or nanotechnology hold some potential. But whether at the frontiers of technology or tried and tested, many of the solutions to agriculture’s dependence on water require knowledge, research and access to forms of innovation. Investing in participatory research that meets the water and production needs of local farmers is therefore critical to reducing water use in agriculture and building the sector’s sustainability.

For a wider analysis of global water security click here.

Groundwater: An Under- and Overexploited Resource

As discussed in Chapter 14, groundwater usage in some areas of the world is well above recharge rates (the rate at which water used is replaced). Indeed 15% of aquifers are being used unsustainably, most notably aquifers in western Mexico, the High Plains and California’s Central Valley in the United States, Saudi Arabia, Iran, northern India and parts of northern China. These aquifers are particularly crucial to agriculture.

Researchers from Canada and the Netherlands have shown, by using global groundwater usage data and models of underground water resources, that for these few aquifers the overextraction rates are so large as to offset the efforts of sustainable management in other areas.  Or in other words for the globe, water use, on average, is higher than recharge rates.

There are also fears that largely untapped underground water reserves under the driest North African countries like Libya, Algeria, Egypt and Sudan may be unsustainably managed.  Mapped by a team from the British Geological Survey and University College London in April these reserves could be a huge buffer against future drought but schemes are already in place in some countries that could undermine this potential. In Libya, for example, the $25 billion Great Manmade River project, implemented under Colonel Gaddafi is planned to provide water to residents of Tripoli, Benghazi and Sirte. The provision of water is planned to be higher than the rate it can recharge itself. At these rates water resources are expected to last about 60 to 100 years.

Marine Fisheries

As stated in Chapter 14, most of the world’s wild fish stock harvest is stagnant or declining. The global harvest captured in the oceans and inland waters has peaked in 2000 at 96 million tons and subsequently fallen to 90 million tons in 2003, remaining at that level until 2009.

Fisheries, like rangelands discussed in Chapter 10, can be conceptualised in terms of a range of possible carrying capacities and sustainable yields, depending on the objectives. If preservation is desired, for example of the world’s whale stocks, an ecological carrying capacity can be sought; it is also possible to maximise the production of high quality sport fish, or of small ‘industrial’ fish. The recent history of the world’s marine fisheries has been an accelerating trend towards industrial fishing, harvesting smaller and smaller fish, not for direct human consumption but for feed. 20 per cent of world production now consists of small pelagic species used for making fishmeal which, in turn, is used in pig and poultry production and in salmon and shrimp aquaculture.

Despite the apparent stability of the oceans, their fish and other populations are as much subject to fluctuation as are rangeland cattle. One of the most productive fisheries in the world, providing 20 per cent of the world’s fish landings in the 1960s and 1970s, is generated by upwellings of cold, nutrient rich waters off the coast of Chile and Peru.