Restoring the IITA Forest

Deni Bown,

Read the Estonian translation by Anna Galovich

IITA lake and forest. Photo by IITA.
IITA lake and forest. Photo by IITA.

In 2010, the International Year of Biodiversity, a new project began at IITA to enhance biodiversity and restore IITA’s Forest. Coincidentally, the United Nations (UN) declared 2011 as the International Year of Forests, and the IITA–Leventis Project is preparing to plant over 30,000 saplings of indigenous tree species this year to restore native forests.

The IITA campus (1000 ha) in Ibadan, Nigeria, now largely within the city limits of Ibadan, was acquired in 1965. The land was mostly bush, interspersed with field crops and 26 villages, whose occupants were relocated. After campus construction and the allocation of fields for crop research, about a third of the site—some 350 ha—was left untouched. In 1987, campus residents created pathways through this regenerating post-abandonment secondary forest, resulting in the Forest Trails we still enjoy today.

After more than 45 years as a reserve, and with continuing loss of forest in southwest Nigeria, this area has become an increasingly important refuge for many plants and animals that were once widespread. Together with an artificial lake at the west margin, the IITA Forest shelters a wealth of animal and plant species and provides a habitat for biodiversity in Nigeria.


The IITA–Leventis Forest Restoration Project aims to:

-Restore the existing forest by removing invasive exotic species, such as Chromolaena odorata, Delonix regia, Gliricidia sepium, Leucaena leucocephala, and Tithonia diversifolia, and replanting the area with indigenous species from seeds, wildlings, and cuttings.

-Protect the IITA Forest against disturbance and theft, in particular, against hunting for bush meat and the collection of medicinal plant parts.

-Catalog the biodiversity of the forested areas, mainly in terms of birds, butterflies, and medicinal plants, and monitor changes.

Junonia cymodoce basking in the sun. Photo by Sz. Safian.
Junonia cymodoce basking in the sun. Photo by Sz. Safian.

-Replant the east bank of the lake with indigenous tree species and carry out research into reforestation techniques.

-Engage in conservation educational activities, especially with young people, to raise awareness of the need to protect forests.

-Form local, regional, and international partnerships in tropical forest conservation, research, and education activities.

The team of rangers and nursery workers from the IITA–Leventis Project is led by Project Manager John Peacock, Project Coordinator and flora/medicinal plant consultant Deni Bown, and Nursery Manager Olukunle Olasupo. In the first year, over 21,000 seedlings of more than 40 indigenous tree species were propagated. Experimental plots were established to record the effects of different ground treatments on the growth of 10 species. Reforesting the east bank was also started by planting trees grown in their first Tree Seed Project by the International School at IITA and by the Institute’s staff.

In addition to the School’s Tree Seed Project, a Garden Club was started to show children how to grow, propagate, harvest, and value edible and medicinal plants. There are regular activities to engage children in observing wildlife and appreciating the forest. Moves are also under way to found a Youth Explorers’ branch of the Nigerian Field Society which will use the resources and expertise at the IITA campus. Educational displays of medicinal plants, butterflies, and photo archives of birds were exhibited at events, and information, both printed and electronic, is provided for the numerous visitors.

Together with the Security Unit at IITA, the team also improved the protection of the Forest.

Ibadan malimbe, an endemic bird species in Nigeria. Source: Leventis Foundation.
Ibadan malimbe, an endemic bird species in Nigeria. Source: Leventis Foundation.

Catalogue of forest resources
The IITA Forest is an internationally acclaimed Important Bird Area (IBA). Since March 2010, over 200 bird species have been identified during surveys by Shiiwua Manu, Phil Hall, John Peacock, Adeniyi Taiye, and Matt Stephens. Similar baseline surveys were carried out for butterflies by Szabolcs Sáfián, Robert Warren, and Oskar Brattström, and brought the total identified in the IITA Forest to 220. Deni Bown has to date recorded 431 plant species at IITA; of these, 382 have medicinal uses.

Flagship species
For many people, the Forest is a place of mystery and beauty but something they may not know much about. By targeting conservation efforts on spectacular species, their interest can be focused. The Project has three flagship species: the Ibadan malimbe, Malimbus ibadanensis, an endangered bird found only in the Ibadan area; the iroko, Milicia excelsa, one of Nigeria’s most important timber trees; and the “PG plant”, Pararistolochia goldieana, a liana (a woody vine) that produces the largest flower in Africa.

Pararistolochia goldieana, a woody vine that produces the largest flower in Africa. Photo by O. Adebayo, IITA.
Pararistolochia goldieana, a woody vine that produces the largest flower in Africa. Photo by O. Adebayo, IITA.

The Iroko is of major economic importance but cannot be grown successfully in plantations. The only place where it is now safe from being felled is within the IITA campus.

Likewise, the Ibadan malimbe and PG plant are totally dependent on the IITA Forest for survival.

Over the past 50 decades, the loss of tropical forests in Nigeria has been catastrophic, giving this fragment in IITA considerable importance. Increasing its extent and biodiversity is part of IITA’s new initiative to conserve biodiversity and create an African Science Park or Innovation Africa™. These are valuable resources for local interests and the wider scientific community.


The time to act is now

Cowpea seedling. Photo by IITA.
Cowpea seedling. Photo by IITA.

For too long, a versatile crop, capable of providing huge benefits for health and wealth stayed on the sidelines, largely below its economic potential and comparatively neglected by research. More recently, however, interest in this grain legume has greatly increased and its benefits have been more widely appreciated and publicized.

Cowpea, or black-eyed pea, is one of the few crops that could positively influence the nutritional status in sub-Saharan Africa. Grown by farmers mostly in West Africa, it is increasingly gaining prominence in the fight against hunger and poverty.

This is reflected in its dual roles as a source of protein for humans that is cheaper than animal products and a way to raise the quality of livestock through improving their feed. Cowpea also provides higher returns on investment than other crops grown in the region where it thrives best.

Harvesting cowpea. Photo by IITA
Harvesting cowpea. Photo by IITA

Unfortunately, support for cowpea research has been relatively low, unlike that for other crops such as wheat and potatoes. Consequently, this has limited the improvement of cowpea.

The situation is not being helped by the negative impact of climate change and unfavorable abiotic factors in the regions where the crop is mostly grown.

Over the years, IITA and its international and local partners have developed solutions to tackle the constraints faced by this “wonder” crop.

These include the development and deployment of improved, Striga-resistant, drought-tolerant, and early maturing varieties. More recently, work is ongoing to produce varieties resistant to the damaging legume pod-borer (Maruca).

Close-up of a cowpea flower. Photo by Christine Peacock
Close-up of a cowpea flower. Photo by Christine Peacock

The impact of these varieties on rural livelihoods and poverty is slowly but surely being felt.

Advances in science could help to further raise cowpea yield. With more resources now going into cowpea research and farmers’ participation in variety selection, even better performing varieties should be available soon.

These efforts have already produced positive results in the target regions but only on a relatively small scale when set in the context of all sub-Saharan Africa.

The task before stakeholders is to join hands with IITA now to advance this crop and to save Africa. The time to act is now.


1 Akara

1/2 pound dried black-eyed peas/ cowpeas
2 onions
1 red pepper
Ground white pepper
Olive oil
2 ripe tomatoes
1 green pepper
1/4 cup chopped parsley leaves

1. Soak peas for 24 hours or overnight in lots of water. Drain. Peel the outside skin from the peas.
2. In a processor, pulse the 1 onion and red pepper to coarsely chop. Add soaked peas and puree to a paste. Transfer to a bowl and using a whisk, whisk the mixture adding salt, white pepper and just a little soaking liquid — not too much as the mixture needs to retain its shape for frying.
3. Using an ice cream scoop, form into balls about the size of a ping-pong ball. Drop into a pot of hot olive oil, heated to around 180 ËšC. Fry until golden brown. Remove and drain on a paper towel-lined plate. Season again with salt and pepper.
4. To serve, make a quick dipping sauce by pulsing 2 de-seeded tomatoes, 1 onion, 1 green pepper, and some parsley in food processor. Add olive oil and season with salt and pepper to make a chunky salsa.

2 Lobia (Black Eyed Beans Curry)

2 cups Lobia (black eyed beans)
1 1/2 tsp
Salt to taste
1 1/2 tsp ground coriander
3/4 tsp ground cumin
1/2 tsp ground turmeric
2 tbsp oil
1 small onion, chopped
2 large cloves garlic, chopped
1 (3/4-inch piece) ginger root, peeled and chopped
1/2 tsp Scant cumin seeds
1 medium tomato, chopped

1. In pot soak beans overnight in water to cover generously. Next day, drain beans, cover with fresh water and bring to boil.
2. Add salt, coriander, cumin and turmeric. Simmer until beans are just tender, about 30 to 45 minutes.
3. Heat oil in deep saucepan. Add onion, garlic, ginger, and cumin.
4. Fry 10 minutes and add tomato. Cook another 5 minutes and add lobia (black eyed beans) and cooking liquid. Continue to simmer, uncovered, until lobia are soft but not completely dissolved. Mixture should be soupy.

Lobia Tomato Masala Curry

1 cup cooked black eyed beans
1 onion, chopped
¼ tsp cumin seeds
¼ tsp fenugreek seeds
Chopped coriander leaves

2 tomatoes, chopped
½ tsp peppercorns
1 tsp coriander seeds
1 tsp fennel seeds
2 tsp poppy seeds
1 tsp cumin seeds
5 garlic pods
3 dry red chillies

Dry fry the peppercorns, coriander seeds, poppy seeds, cumin seeds, and fennel seeds and simmer for a while. Add the fried seeds and tomatoes, garlic pods with 1 cup water and grind them coarsely. Then add ¼ cup of the cooked black eyed beans to the spices and grind everything as a fine paste.

Heat oil in a pan, add the cumin seeds n fenugreek seeds and let them splutter. Add the chopped onion and stir them until they turn translucent. Next, add the grounded paste and simmer for a while. The mixture will stick very easily to the bottom of the pan, so keep on stirring, adding enough water and salt to the gravy. Once the oil separates from the gravy, add the rest of the black eyed beans and cook the mixture for a few more minutes. Add the chopped coriander leaves, and then turn off the stove.

3 Red-Red (Cowpea stew, also known as Black Eyed Pea Stew)
A traditional Ghanaian recipe for a classic stew of black-eyed peas in a tomato and red palm oil sauce that’s usually served with fried plantain. It might have bene named for the combination of red pepper and red palm oil.

240 g black-eyed peas (cooked)
1 medium onion, sliced
2 large tomatoes, finely chopped
1/2 tbsp chilli powder
2 tbsp red palm oil (or 2 tbsp groundnut oil + 1/2 tsp paprika)
salt and black pepper to taste

1. Soak the black-eyed peas in water for at least an hour or overnight. After soaking them, rub them together between your hands to remove the skins. Rinse to wash away the skins and any other debris. Drain them in a colander.
2. Mash the black-eyed peas and set aside.
3. Heat the oil in a pan and cook the onion and tomatoes until soft. Add all the remaining ingredients (including the peas) and simmer for 10 minutes.
4. While peas and sauce is simmering, prepare fried plantains.
5. Serve peas and plantains side by side on a plate.

4 Hoppin’ John

• 1 1/2 cups dry black-eyed peas
• 1 pound ham hocks
• 1 onion, chopped
• 1/2 teaspoon crushed red pepper flakes
• salt and pepper to taste
• 4 cups water
• 1 1/2 cups long-grain white rice
• 1 cup shredded smoked Cheddar cheese

1. In a large pan place the peas, ham hock, onion, red pepper, salt and pepper. Cover with water and bring to a boil. Reduce heat to medium-low and cook for 1 1/2 hours.
2. Remove ham hock and cut meat into pieces. Return meat to pot. Stir in the rice, cover and cook until rice is tender, about 20 to 25 minutes. Season to taste with salt and pepper. Sprinkle shredded cheese over top, if desired. Serve.


1. Cowpeas are thought to get their name from when they were a key livestock feed in the USA.

2. The cowpea is 25% protein.

3. Fifty two percent of the cowpeas produced in Africa are used for food, 13% are used for animal feed, 10% are used for their seeds, 9% goes to other uses, and 16% are wasted.

4. In the Southern United States eating black-eyed peas on New Year’s Day is considered good luck because they symbolize money.

5. In Yoruba cowpeas are called ewa or ere. In Hausa they are known as wanke. And across the French-speaking regions of West Africa they are called niebe.

Victor Manyong: Strengthen socioscience capacity

Victor Manyong, R4D director. Photo by IITA.
Victor Manyong, R4D director. Photo by IITA.

Victor Manyong, IITA’s director for eastern and central Africa, talks about his 17-year experience with the institute as an agricultural economist and his vision for the institute’s socioscience research.

Can you give us a brief outline of your career at IITA?
I joined IITA in 1992 as a postdoc fellow based at Ibadan, Nigeria. I was recruited to head a project covering 11 countries in West and Central Africa on the GIS-based macro-characterization of agricultural systems. It was a challenging 2-year research but I had a 1-year extension during which the institute’s agricultural economist left. I applied and was offered the position. Then, I became a scientist and was first posted to the moist savanna project within the Resource and Crop Management Division.

As CG centers moved to a project-based approach, I was asked to lead and coordinate the project on social science research. When the DG, Hartmann, came on board, he introduced the Research for Development Council (RDC) to help him in strategic issues. I became a member of the first interim council. A year later, I was elected to serve as a council member, so I had to step down as a coordinator of social science research.

After serving a 2-year term, I left RDC and became an ordinary agricultural economist until 2005 when I was relocated to Tanzania. Here, I occupied the new position of agricultural economist for East and Southern Africa. I was also appointed the Officer in Charge of the station in 2006.

What challenges did you encounter in your move from West to East Africa?
It was a challenge to establish myself in a new environment, to establish a new research agenda for the institute, define my research priorities that fit in with the institute’s priorities, and to fit in with the existing team. It also was a challenge to build and strengthen a new network of partners.

What can you say about the status of social science research at IITA?
IITA is a commodity and natural resources management center in the CG system. Hence, social science is embedded in its research agenda. The strength of social science research at IITA is that we are working with the biophysical scientists, such as breeders, plant pathologists, and so on to create a very strong multidisciplinary team where members benefit from one another.

One problem is that we cannot have all the disciplines of social science research we need because of resource limitation. IITA’s social science has been dominated by agricultural economics while areas such as anthropology, rural sociology, political economy, and market economy have not been well addressed.

However, the institute is making efforts to remedy the situation. Currently we are recruiting a market economist. We also aim to have an anthropologist.

What does the agricultural economist at IITA do?
We work with other scientists in designing new technologies by looking at their economic profitability and social acceptability. A technology may be good but if it is not profitable or if it is rejected by the intended users, then it will not work. We contribute to studies related to the institute’s priority setting. The agricultural economists also monitor the adoption of improved technologies, measure the benefit to the end users, determine the difference the technologies make, influence policies, and are involved in the capacity building of young professionals.

Currently you are a director for R4D. What does this entail?
I am a member of the R4D directorate handling the eastern and central African region covering about 11 countries. I oversee our stations in Cameroon, DRC, Kenya, Uganda, and Tanzania. As a member of the R4D Directorate, I work under the DDG-R4D to provide leadership on all R4D-related issues at IITA.

What challenges have you encountered in the transition from a scientist to an administrator?
Before I became the director, I was the OIC in Tanzania and a scientist. After the appointment, I now have to handle three functions: that of a scientist, OIC, and director. There obviously is the additional workload. I therefore needed to get organized to manage all the tasks.

I am also now managing more human resources, looking at relationships with government and other officials, and am the institute’s representative to the public. I needed managerial skills and to cope, I put in a lot of extra time. Currently my tasks are lighter because my duties have been reduced to those of the director and the country representative for Tanzania.

What are some of the highlights of your stay at IITA?
I have many but one of them was in 2005 when I published my first book that focused on agriculture in Nigeria. For a researcher this was an important milestone. The other highlight is contributing to the development of IITA’s regional hub for East and Central Africa in Tanzania. I am also lucky to have greatly contributed to mentoring young professionals at IITA and training of many in social science in Africa. Some of them are working as colleagues in international organizations or as professors in universities.

What changes have you noted at IITA over the years?
I have noticed many changes, all positive. The institute has really grown, becoming more stable. Financially, we have moved from an annual budget of $35 million to the current $50 million. And IITA rates well in research and quality of science among the CG centers. I have also witnessed the decentralization of our research activities. When I first joined, everything was done from Ibadan. The decentralization has brought the scientists closer to the fields of operation outside West Africa. For many years, IITA was considered an institute for West and Central Africa. This is no longer the case.

How can the institute sustain its growth and progress?
We need to consolidate our research in the decentralized mode of operations to strengthen the regional hubs but not at the expense of West Africa. We also should not ignore the reforms taking place in the CG. We need to see how the institute can evolve in the new consortium of CG centers.

What would you like social science at IITA to look like, say in five years time?
I would like to see a more diversified group of social scientists. We need to strengthen the areas of qualitative social science research and on markets. The current thinking is that one economist can do all research related to social science. I disagree. For example, can one breeder breed all crops? At IITA we have breeders of maize, cassava, cowpea, and yam, etc. So, when it comes to social research, we need a diversified group of social scientists.

Socioscience is also wanting at the NARS where the social scientists are always lured away by better-paying NGOs. We build their capacity but when they are ready they move on and we have to start again when they recruit new members. One solution is to link up with universities where we have more permanent social scientists.

What has contributed to your success?
I attribute my success (if any) to the support I receive from the management. They have always made me feel that my work is important and that it is valued. I also would like to acknowledge the support and collaboration with partners and colleagues within and outside the institution.
On research management, I am part of a great team where members support one another. We have good leadership and good support from management. I have also been lucky to work in my area of expertise.

What would you have been if not an agricultural economist?
Well, I resisted a lot of pressure from my family to study medicine and become a medical doctor. I have always liked agriculture. I moved 2,000 km from my home town in Lubumbashi (DRC) to study agriculture at the then unique country Faculty of Agriculture in Kisangani. The person who stoked my interest in agricultural economics was Prof Eric Tollens, currently at KU Leuven (Belgium) and a former IITA Board member. When I joined the Faculty of Agriculture in Kisangani, he was then a professor and chair of the Department of Agricultural Economics. I listened to his talk, and I knew what I wanted to be.

Ousmane Boukar: Cowpea improvement for food security and poverty alleviation

Ousmane Boukar, IITA cowpea breeder, Kano, Nigeria. Photo by IITA.
Ousmane Boukar, IITA cowpea breeder, Kano, Nigeria. Photo by IITA.

Ousmane Boukar is IITA’s cowpea breeder and the Station Representative in Kano, Nigeria. He has been with IITA since 2007. As a breeder, his aim is to mine IITA’s germplasm collection of cowpea to identify important additional sources of gene(s) of interest for resistance to both biotic and abiotic stresses, sources of consumers and producers’ preferred traits, etc. This will broaden cowpea’s genetic diversity to contribute efficiently and significantly to cowpea genetic improvement.

Please describe your work.
My work in IITA is exciting and very challenging. IITA offers a lot of opportunities to contribute to the livelihood of millions of people mainly in sub-Saharan Africa through the improvement of the agriculture sector. I believe that playing a role in cowpea improvement means participating in enhancing food security and poverty alleviation of millions of people in Africa.

What are the current thrusts and initiatives on cowpea breeding?
The cowpea breeding program is focused on identifying additional sources of resistance to pests and diseases, combating parasitic weeds, improving drought tolerance and adaptation to low soil fertility. Our strategy is to consolidate the progress so far achieved and to establish a very strong foundation for further genetic improvement. The aim is to increase production in terms of both fodder and grain yields, and those plant and grain characteristics preferred by consumers and producers. Efforts would also be made to enhance the level of micronutrients and protein in cowpea grains. African rural and sub-urban communities will be able to produce more high quality products for human and animal consumption, to improve their health by providing a balanced diet, and their income by providing enough for home consumption and supply to markets.

Major projects associated with cowpea improvement include Tropical Legumes I and II, Purdue Improved Cowpea Storage, Development and promotion of Alectra-resistant cowpea cultivars, the Application of marker-assisted selection for Striga resistance in cowpea, Improving drought tolerance phenotyping in cowpea, Appropriate Variety of Early maturing Cowpea for Burkina Faso (AVEC-BF), and Development of parasitic weed control methods for world food security.

Cowpea field experiments, IITA. Photo by C. Ono-Raphael, IITA.
Cowpea field experiments, IITA. Photo by C. Ono-Raphael, IITA.

What are the major challenges in cowpea improvement?
Cowpea production is limited by numerous factors both biotic and abiotic which could be addressed using the tools from genetic improvement. Several diseases, insect pests, nematodes, and parasitic weeds cause significant cowpea yield loss. Abiotic constraints include drought and heat which also cause significant yield reduction during the seedling and/or reproductive stages of the crop. Another major production constraint is low soil fertility from organic matter and low phosphorus availability, particularly in the soils of the savannas.

The range of production environments and cropping systems and the diverse preferences among consumers and producers for grain, leaves, pods, and fodder, make cowpea breeding very challenging. There is a clear need to develop a range of varieties that meet the diverse requirements combining high yield potential and resistance to the major production constraints.

How do you decide which challenges to address?
Identification of areas of research involves all stakeholders along the cowpea value chain. We consider both the current and long-term needs of our stakeholders. The current needs are determined from observations in our research fields, farmers’ fields, the attitudes of consumers, and in our interactions with farmers, NARS colleagues, NGOs, traditional and political leaders through farmers’ field days, farmers’ participatory varietal selection, and participation in meetings. The long-term needs are based on our own experiences and those of colleagues. This approach guarantees the continued relevance of our research activities. The various projects enable me to have a good interaction with all the stakeholders.

Who are IITA’s partners in cowpea improvement research?
NARES, advanced research institutions (ARI), NGOs, farmers, traditional and political leaders. Our activities on drought tolerance, for example, involve national and international partners (Mali, Niger, Nigeria, Mozambique, Tanzania, Burkina, and Senegal; and University of California, Riverside). Our Striga and Alectra research activities involve both NARS (Burkina, Senegal, Niger, Mali, and Cameroon for Striga and Malawi and Tanzania for Alectra) and ARIs (University of Virginia for Striga and Natural Resources Institute for Alectra). Our partners are involved right from the initial stages of the projects.

Why is cowpea underexploited and underutilized?
The main reason is that cowpea is a crop grown by poor people for consumption and commercial value in the local regions. This makes the crop unattractive to commercial breeding and seed companies and ensures a lower priority for developed countries.

Sub-Saharan Africa accounts for 70% of the world cowpea production. What could be done to ensure that cowpea receives research attention?
Almost all African governments consider agriculture as the main basis of their economic development. Very good strategies are being developed but unfortunately these strategies are not followed through always! Funding for cowpea research will enable the research institutes and universities to compete for external funding. Very few governments are supporting their research institutions by facilitating contacts or lobbying through major donors.

What new tools are being used to hasten cowpea improvement work?
With the rapid advances in plant genomics and molecular biology, new tools are being developed. Also, the use of molecular breeding combined with conventional breeding is becoming possible in cowpea improvement. A few steps are already being applied in cowpea improvement through marker-assisted selection and genetic modification. With the development of the recent well-saturated consensus genetic map, cowpea improvement is ready to benefit from an increased efficiency of selection resulting from the application of molecular breeding. Tropical Legume I phase II will soon give us an opportunity to test the efficiency and effectiveness of molecular breeding in cowpea.

What are the recent developments and breakthroughs in cowpea breeding that farmers and producers, including processors, could look forward to?
Our intensive activities through the Tropical Legumes II project have led to the identification and release of some drought-tolerant breeding lines. For example, in 2008, IT97K-499-35 was released in Nigeria. The performance of this variety has impressed farmers in Mali who named it jiffigui which means “hope”. Additional adaptation trials are being conducted in Mali and Niger for the release of this line.

Another example is IT00K-1263. This has shown good performance in Mozambique and Tanzania and is being considered for release soon in these countries. Additional sources of improved P-use and resistance to aphids, bacterial blight, multiple virus, Striga, and drought have been identified and segregating populations have been developed. New breeding lines with drought tolerance and multiple disease, and insect and Striga resistance will be available in the near future.

Farmers' participatory varietal selection, northern Nigeria. Photo by IITA.
Farmers' participatory varietal selection, northern Nigeria. Photo by IITA.

How do you involve farmers and producers in your work?
Through farmers’ participatory variety selection (FPVS). This consists of bringing groups of farmers to the field where they can select 2 to 3 varieties that they prefer out of about 20−30 lines. Varieties developed through this approach have showed a higher rate of adoption by the farmers. In addition, farmers’ field days and baseline studies enable us to learn from farmers about their main production constraints and their preferences in terms of plant type, maturity type, and grain and fodder quality. All the information collected is being incorporated in our breeding objectives.

How could IITA make stakeholders pay more attention to cowpea?
For more than four decades, IITA scientists had been working on different aspects of cowpea improvement. By documenting the role of cowpea in the livelihood of people in sub-Saharan Africa, the importance of major cowpea production constraints, the progress so far achieved, and strategies for the future, and by maintaining the world’s collection of germplasm for this crop IITA will continue to make donors and other stakeholders more interested on cowpea.

James M. Lowenberg-Deboer: Ensuring Africa’s future through agriculture

James Lowenberg-DeBoer, Purdue University. Photo from J. Lowenberg-DeBoer.
James Lowenberg-DeBoer, Purdue University. Photo from J. Lowenberg-DeBoer.

James M. Lowenberg-DeBoer, or Jess, has 24 years of worldwide experience in agricultural research, teaching, outreach, and administration. He currently serves as Associate Dean and Director of International Programs in Agriculture (IPIA) at Purdue University, coordinating all international programs for the Purdue College of Agriculture.

His research focuses on the economics of agricultural technology. He brings to his research, teaching, outreach, and administration a perspective gained through private sector experience as a farmer and journalist.

Please describe your work.
I have participated in every step of the cowpea value chain in Africa from production to consumption. I have helped cowpea breeders define their genetic strategy, collaborated with entomologists on pest management in cowpea fields, partnered with extension specialists to transfer improved cowpea storage technologies, and worked with food scientists to reduce the labor required to make cowpea-based street foods. I have even initiated some exploratory research on the economics of cowpea leaves as a green vegetable. Most recently, I focused on the Purdue Improved Cowpea Storage (PICS) project, teaching farmers and cowpea traders how to use hermetic storage methods to reduce damage without insecticides and developing the supply chain for the heavy duty plastic bags that are, in most cases, the most cost-effective hermetic storage container.

How important is cowpea in the American diet and economy?
Cowpea is a specialty item in the American diet and economy. It is commonly known as “black-eyed peas” in the US because the varieties found in supermarkets are usually white with black eyes.
Many Americans eat cowpea in traditional dishes associated with holidays. For instance some Americans eat “hopping john”, a dish made of cowpea and rice on New Year’s Day. “Southern peas,” cowpea that is picked before maturity and eaten as a vegetable, are widely consumed in the Southeastern US. Some families have heirloom cowpea seed varieties that are passed down from parents to children, and grown each year in the household garden.

On US farms cowpea is a specialty crop grown on roughly 92,000 ha annually. Dry cowpea grain is produced on only about 12,000 ha annually, mostly in California and Texas. Southern peas are produced mostly in the southeastern US, mainly in home and market gardens. Because they are not a large-scale commercial crop, the government does not collect statistics on production, but informal estimates indicate that up to 80,000 ha of cowpea in the US is used annually as southern peas.

How did you get started in cowpea research?
I started working on cowpeas when I was a researcher at the National Institute of Agricultural Research of Niger (INRAN) from 1988 to 1992. Niger exports more cowpea than any other country in the world. The crop is very important for the Nigerien economy and for Nigerien farmers.
In West and Central Africa, the demand for cowpea is very strong, particularly in Nigeria. Farmers could increase cowpea production with the assurance that there would be a market for their product. Urban people, particularly the urban poor, benefit from cowpea because it is a relatively low-cost, high-protein food that does not require refrigeration. Improvement in cowpea production, storage, and marketing would benefit millions of people. In short, cowpea research allowed me to maximize my impact as a scientist.

Please describe your collaborative work with IITA.
I have worked with almost every IITA cowpea researcher. For example, B.B. Singh and Ousmane Boukar used the consumer preference research done by my students and I do to help determine the goals of their breeding efforts. I collaborated with Ousmane Coulibaly to assess the reactions of potential producers and consumers to genetically modified cowpea. Over many years, I have worked closely with Tahirou Abdoulaye, most recently in assessing the impact of the PICS project.

What are the major constraints in cowpea research and development?
Twenty years ago when I started working on cowpea issues, farmers usually said that their most pressing problem was storage. They said that they would produce more cowpea if only they could store it safely until they needed it for household consumption or until prices made marketing profitable.

Today, farmers in the current PICS countries usually say that management of field insects is their major problem. They say that PICS has provided a cost-effective solution to the storage problem. It is hard to predict which cowpea constraint will be the most serious in the future, but I think we should pay attention to two issues: soil fertility and consumers’ demand.

In general, African soils are becoming degraded. Like most legumes, cowpea is very sensitive to soil phosphate levels. World phosphate stocks are decreasing and the price of phosphate fertilizer is trending upward. We should think about breeding cowpea varieties that make better use of the phosphates in the soil and we need to consider how to recycle urban wastes and livestock manure to return the phosphates from cowpea grain and forage to the soil.

Any other concerns?
My concern about cowpea demand is related to economic growth. In many countries in the world, when incomes rise, people want more animal-based protein and more convenient foods. For instance, in some Latin American countries, consumption of beans per capita is declining as people switch to meat, milk, and eggs.

For economic, nutritional, and environmental reasons, it is important that people everywhere continue to consume grain legumes, especially cowpea. In West and Central Africa, that means we need to educate consumers on the benefits of eating cowpea and we need to work with food scientists to develop labor-saving forms of traditional cowpea-based foods. For example, we hope that our work on coarse cowpea flour can be used to make cowpea fritters (i.e., akara or kossai) or cowpea dumplings (i.e., dan waké) without the laborious traditional wet milling process. This will help to keep cowpea foods in family meals and on street vendors’ stalls.

James Lowenberg-DeBoer interviewing a vendor in Accra, Ghana. Photo from J. Lowenberg-DeBoer.
James Lowenberg-DeBoer interviewing a vendor in Accra, Ghana. Photo from J. Lowenberg-DeBoer.

What do you think is the future of cowpea in Africa?
Cowpea is a great grain legume crop for the low-altitude tropics. Because it is very heat and drought tolerant, cowpea is ideal for semi-arid areas.

The single greatest threat to the future of cowpea in Africa is that it will be displaced by other crops that have greater research backing. For example, soybean benefits from the extensive research done in the US, China, Japan, and other temperate zone countries. To a lesser extent, the same is true for the common bean. In spite of cowpea’s natural advantages, African farmers may be obliged by economic forces to switch to producing other crops for which research develops greater heat, drought, resistance to pests and diseases; and crops for which food science and marketing develop alternative high-value uses. The future of cowpea in Africa depends on maintaining and developing a research community that will allow this species to fulfill its potential.

How could farmers and producers cash in on cowpea?
African farmers are already cashing in on cowpea. In the Sahelian countries, cowpea is often the only viable cash crop. If science finds a solution to the field pest management problems, we can expect a much greater production in the humid zones of West and Central Africa. To realize profits on cowpea with current technology, farmers have improved varieties, soil fertility management methods, pest management techniques, and storage technologies. They need to determine which combination works for them. Like farmers in industrialized countries, African producers of cowpea need to be attentive to new technology. Economics dictate that the biggest benefits from new technology go to the early adopters.

How would you describe your experiences in working in Africa?
I have worked on every continent which has agriculture. My work in Africa has been the most professionally and personally satisfying. I think this is because in Africa the need is great and the potential is even greater. Per capita food production in Africa has been declining for decades, but Africa is also the area with the greatest potential for increased food production. In the rest of the world, most of the land that can be farmed is already farmed intensively. In Africa, land that is farmed is mostly cultivated with the most extensive methods and there is still land to be developed for agriculture.

Africa is the future of agriculture and agribusiness. I am pleased to have played a small role in the research that is building African agriculture and a slightly larger role in training the African scientists who will help Africa to realize its agricultural potential.

Irvin E. Widders: Perspectives on CRSP training

Irvin E. Widders, CRSP, MSU. Photo from I. Widders.
Irvin E. Widders, CRSP, MSU. Photo from I. Widders.

Irvin E. Widders is the Director of the Dry Grain Pulses Collaborative Research Support Program (CRSP) based in Michigan State University (Program Management Entity).

Irvin has directed the Pulse CRSP since 2007 and the Bean/Cowpea CRSP from 2000 to 2007. He provides technical leadership to the program and monitors the technical performance of subcontracted projects so as to ensure that the program achieves its global objectives and development goals. He also serves as the primary link with program advisory groups and cultivates collaborative partnerships with institutions involved in pulse research and technology transfer in developing countries of sub-Saharan Africa and Latin America, as well as with private pulse industry groups.

The Pulse CRSP is supported by the USAID. It is one of the organizers of the 5th World Cowpea Research Conference currently being held in Saly, Senegal.

Tell us about the Dry Grain Pulses CRSP.
The Dry Grain Pulses CRSP aims to contribute to economic growth and food and nutritional security through knowledge and technology generation on pulses (e.g., common bean, cowpea, pigeon pea, lima bean, etc.); sustainable growth, and competitiveness of pulse value chains using socially and environmentally compatible approaches; empowerment and strengthened capacity of agriculture research institutions in countries in Africa and Latin America; USAID’s development objectives as defined by the Feed the Future Initiative; and dual benefits to developing country and US agriculture.

What are its objectives?
The Pulse CRSP’s objectives are to (1) reduce bean and cowpea production costs and risks for enhanced profitability and competitiveness, (2) increase the use of bean and cowpea grain, food products, and ingredients so as to expand market opportunities and improve community nutrition and health, (3) improve the performance and sustainability for bean and cowpea value chains, especially for the benefit of women, and (4) increase the capacity, effectiveness, and sustainability of agriculture research institutions that serve the bean and cowpea sectors and developing country agriculture in sub-Saharan Africa and Latin America.

Why a CRSP on pulses?
The international community of scientists in the Dry Grain Pulses CRSP believes that cowpeas are a strategic solution to the global challenges of nutritional security, worldwide climate change, and the sustainability of cropping systems. Cowpea is a staple food, providing fresh peas, leaves, and nutrient-dense dry grain to countless millions of people in Africa, Asia, and Latin America. It is highly tolerant of drought and high temperatures; it biologically fixes nitrogen and generates an economic return for small-scale resource-poor farmers.

What are some of the exciting initiatives of CRSP?

Current research and outreach initiatives are undertaken in partnership with national agriculture research systems and agricultural universities in Africa that benefit stakeholders of cowpea value chains. These include the following:
a. The use of “omics” tools to deploy and manage biological controls for insect pests on cowpea in West Africa.
b. The breeding and dissemination of cowpea varieties with drought tolerance, resistance to economically important biotic constraints and improved grain culinary quality traits.
c. The determination of the influence of natural phytochemical constituents of cowpeas on metabolic, cardiovascular, and chemo-protective human health predictors in in-vitro systems.
d. The assessment of the effects of cowpea and bean consumption by HIV-infected children (through nutritional interventions) on nutritional status and CD-4 counts.

Farmer field school in Niger. Photo from I. Wiiders, MSU.
Farmer field school in Niger. Photo from I. Wiiders, MSU.

Please explain CRSP’s approach to capacity building.
Capacity building of host country collaborating institutions is central to the mandate of the CRSPs since their inception in the early 1980s. The CRSP approach is to empower host country institutions to address agricultural constraints and opportunities through the creation of new technologies and knowledge while concurrently developing human resource capacity and competencies in strategic areas of agricultural science. This leads to institutional self-reliance and sustainability. The CRSPs support the efforts of NARS, agricultural universities in developing countries, and international agricultural research centers to enhance capacity through human resource development, professional consultations, and facilities and infrastructure improvement.
The need for additional professionals to contribute to the development of pulse value chains is never ending. New professions are needed in diverse disciplines to provide leadership to the continued development and competitiveness of the cowpea and bean sectors.

What is CRSP’s strength?
Institutional capacity building is an area where US universities, through the CRSPs, have comparative advantage over other development programs. US universities are academic institutions in the business of human resource development; educating and preparing leaders to face the challenges of an ever-changing and complex world. Universities can effectively design and implement innovative, flexible, and cost-effective institutional capacity building initiatives as well as professional development programs.

What are some of CRSP’s achievements?
If one looks over cowpea and bean research in Africa and Latin America, one would be impressed with the impact of the Bean/Cowpea (1980-2007) and the Dry Grain Pulses CRSP on human resource development—perhaps our greatest legacy. It is estimated that nearly 680 individuals received Master’s and PhD degrees with full or partial support through these CRSPs. The encouraging news is that over 60% of CRSP trainees are back in their home countries and continue to work in support of the cowpea and bean sectors. The most valuable knowledge/skill/attitude acquired through the CRSP training was “the ability to design, conduct, and analyze scientific research” as a result of being mentored by a CRSP university professor.

What are some of CRSP’s challenges?
The program has yet to achieve its intended developmental outcomes and impact. Small-scale resource-poor pulse (cowpea) farmers are still struggling to provide for household food and nutritional security needs, as revealed by the recent food crisis ( The keys to success in technology transfer and to catalyzing the growth of cowpea value chains are complex and often unique for each situation.

The greatest challenge is to achieve sustainable improvements in various sectors of a value chain. It is relatively easy to place quality seeds of improved varieties of cowpea in the hands of large numbers of farmers. However, it is extremely challenging to develop sustainable seed systems in which pulse farmers assume responsibility for the production of quality declared/certified seeds at an affordable price. Many programs have also been unsuccessful in getting farmers to recognize the value of planting quality seeds of specific improved varieties that will provide yield increases, provide grain of types demanded by markets, and with desired culinary traits, thus justifying an increased price and a willingness to pay for “improved seeds”.

How could collaborative programs be more effective in addressing the needs of partners and farmers?
It is imperative that all programs supporting research and technology transfer efforts on pulses (e.g., cowpea), including the private sector, cooperate to ensure more focused attention to priority constraints, to identify technologies and policies that will enable small-scale farmers to compete in domestic and regional markets, and to coordinate their strategy and activities.

To be successful in stimulating the development and growth of functional and sustainable pulse value chains in Africa and Latin America, governments and donors must continue to make balanced investments in both research and technology transfer. Recent advances in science afford opportunities to greatly benefit small holder pulse/cowpea farmers. The cowpea research community must, however, assume greater responsibility to work directly with private sector groups and NGOs to ensure that future outputs of research are appropriate and are extended to the target beneficiaries.

New approaches to assessing soil conservation options

Birte Junge,

Land degradation has become a global concern as it affects the environment, agronomic productivity, food security, and quality of life (Eswaran et al. 2001). Due to rapid population growth, land use has been intensified to cover the increased demand for food. This often results in the loss of soil and nutrients when land is not used properly.

Change in village area, Badume, Kano State, Nigeria. Image from B. Junge.
Change in village area, Badume, Kano State, Nigeria. Image from B. Junge.

Processes that degrade soil include the loss of topsoil by the action of water or wind; chemical deterioration, such as nutrient depletion; physical degradation, such as compaction; and biological deterioration of the natural resource which includes, among others, the reduction of soil biodiversity (Lal 2001).

In Nigeria, where the population dramatically increased from 115 million in 1991 to 140 million in 2006 (FRN 2007), human-induced soil degradation is a common phenomenon: its severity is low for 37.5% of the area (342,917 km2), moderate for 4.3% (39,440 km2), high for 26.3% (240,495 km2), and very high for 27.9% (255,167 km2) (FAO 2005).

Soil erosion is the most widespread type of soil degradation in the country and has long been recognized as a serious problem (Stamp 1938). In 1989, 693,000 km2 were already characterized by runoff-induced soil loss in the south. In the north, 231,000 km2 were degraded, mainly by wind erosion. Sheet erosion is observed all over the country. Rill and gully erosion are common in the east and along rivers in northern Nigeria (Ologe 1978, Igbozurike et al. 1989).

Soil erosion degrades the natural resource base, resulting in the loss of land for farming or grazing animals, as well as off-site problems, such as the sedimentation of dams. Reduced agricultural production, food insecurity, low income for the rural population, and poverty are some of the consequences. Thus, more emphasis has to be put on avoiding soil loss through improved management to conserve the natural resources for today and the future.

Monitoring land use intensification and soil degradation
A German Federal Ministry for Economic Cooperation and Development/German Society for Technical Cooperation (BMZ/GTZ) project from 2005 to 2008 included the study of soil erosion and its causes using different methodologies, such as remote sensing and the geographic information system (GIS) technology. Aerial photos and satellite images produced at different dates and scales and GIS can be used to obtain key information on environmental resources and their degradation (Oluseyi 2002).

Remote sensing data: aerial photograph, 1962/1981. Image from B. Junge.
Remote sensing data: aerial photograph, 1962/1981. Image from B. Junge.
Remote sensing data: IKONOS, 2005. Image from B. Junge.
Remote sensing data: IKONOS, 2005. Image from B. Junge.
Remote sensing data: Quickbird, 2005/06/07. Image from B. Junge.
Remote sensing data: Quickbird, 2005/06/07. Image from B. Junge.

Badume (12°19’N 8°31’E), Kayawa (11°22’N 7°20’E), Gadza (8°98’N 6°00’E), and Eglime (7°08’N 1°67’E), villages located in different agroecological zones of Nigeria and Bénin, were selected as study sites. Historical aerial photos (from 1962, 1981, or 1982) and recent satellite images (IKONOS imagery with spatial resolution of 1 m from 2000; and QuickBird imagery with spatial resolution of 0.6 m from 2005 to 2007) were analyzed to study the change in land use/land cover (LULC) and soil degradation in these places.

A manual interpretation approach was used to identify the LULC classes of the study areas. Verification was done in the field with local farmers and by using the global positioning system (GPS) to obtain the accurate location of the former and present village boundaries and to get point data for the LULC classes. In addition, the average growth rate of several gullies in each village was measured for use in forecasting possible expansion in the future.

Change in LULC
The interpretation of historical and recent remote sensing data showed that the area of all settlements expanded within the last decades and years. For example, the village of Badume increased from 0.9 ha (1962) to 4.3 ha (2006), an expansion of 3.4 ha in 44 years. The rate of increase was slower in former times than in recent years. This reflects the recent rise in population.
The area in use around the pilot villages also expanded within the period considered. For example, the area of Kayawa increased from 166.8 ha to about 438.6 ha, an expansion of 272.6 ha in 44 years. The rate of increase was much higher in former times than in recent years, with more of the uncultivated land available around the settlements being converted into farmland. No uncultivated land was/is available for expansion any longer, since the borders with neighboring villages had been reached.

The areas covered with trees or shrubs generally decreased in the pilot villages. For instance, in Gadza, the area decreased by 4.8 ha from 2000 to 2005. Causes are conversion into farmland, but also the uncontrolled exploitation of these areas for fuelwood (Odihi 2003), timber (Okoro 1990), or logging (Omo-Irabo and Odunyemi 2007). The reduction or elimination of fallow was especially observable in Badume and Kayawa, but not so severe in Gadza where fallow still covered a certain percentage of the village area. The reason might be the production of cash crops in inland valleys—the “fadama”—which ensures a certain income. Uncultivated areas in the surroundings of the fields also decreased during the period under consideration. Having less land is a constraint to livestock production for the Fulani (migrant farmers) who need to graze their animals. Conflicts between arable farmers and pastoralists already take place in the pilot villages because of competition for limited land resources.

Change in soil degradation
The study sites located in the Sudan and northern Guinea savanna were characterized by sheet erosion. In Badume, the eroded area near the river sites increased from 11.6 ha in 2000 to 12.3 ha in 2006. In Kayawa, sheet erosion was a big problem, especially in the western part of the village area. Land characterized by sheet erosion (7.9 ha) was already visible on the photo in 1962 and increased to 32.3 ha in 2006.

Gully erosion, Badume, Kano State, Nigeria, 2000 (left) and 2006 (right).
Gully erosion, Badume, Kano State, Nigeria, 2000 (left) and 2006 (right).

Erosion gullies were also detected along the rivers in the uncultivated area of Badume and Kayawa. The study of two gullies located northeast of the village area of Badume revealed that the degraded land increased from 37.9 ha (2000) to 45.1 ha (2006). In Kayawa, gully erosion also increased. In 1962, about 1.5 ha of the village area was destroyed by gullies. This area increased to 13.1 ha in 2000 and to 15.5 ha in 2006. Reasons include the high impact of the rain at the beginning of the wet season after the total removal of crop residues during the dry season (Odunze 2003) and the formation of ridges along the slope that increase the velocity of runoff and hence, the removal of topsoil (Lal 1995). The herds of cattle that graze on the land or pass it on their way to watering pits or other pastures are very destructive. The frequent shortage of grass, overgrazing, and trampling by animals result in a sparse vegetation cover that exposes bare soil and accelerates the formation of runoff and the removal of topsoil (Azeza and Omeji 1985).

The uncultivated area surrounding Gadza was characterized by a huge network of deeply worn animal tracks mainly located between a Fulani settlement and the Gadza River. These pathways were carved to different extents, depending on their location and the frequency of animal passage. During heavy rain, the transport of runoff and sediment was observed, resulting in the removal of fine particles and the accumulation of sand and gravel. In 2000, about 17 km of track-gullies already existed; this increased to 83.7 km in 2005. This immense increase of 66.7 km in 5 years might be caused by the higher resolution of the recent QuickBird images which facilitated the detection of small tracks. Another reason might be the increase in the number of cattle causing these linear erosion features.

No erosion gullies were detected on the aerial photograph of Eglime made in 1982. This might be caused by the small scale of the picture and its bad quality, as elderly farmers remember the presence of some erosion features from their childhood. In 2000, gullies with a total length of 4.4 km were observed and this total increased to 42.2 km in 2007. Reasons for this big increase are the good quality of recent images and the change in LULC. The farm area has increased within the last decades with the promotion of cotton cultivation. This crop is known for its low canopy cover and, hence, for reduced protection of the soil surface against the impact of rain drops (Junge 2004).

Based on calculated gully growth rates, the estimation of possible future expansion of areas degraded by gully erosion showed an increase for all pilot villages, but to different extents. In Badume, 3.0 ha and in Kayawa, 4.7 ha are expected to be eroded in 10 years. The gullies in Gadza, developed from animal tracks, will cover an area of about 1.2 ha in the following decade, and in Eglime, 2.3 ha of land will be lost to gully erosion.

Using remote sensing and GIS
The interpretation of remote sensing data produced at different dates and of pilot villages in different agroecological zones of Nigeria and Bénin has shown that the village area, farmland, and settlement expanded at all sites. Farmland increased at the expense of areas usually covered with forest and shrubs, fallow, and grazing land.

The consequences of this land use intensification were detected in all study sites in the form of sheet and gully erosion. The removal of soil including organic matter and nutrients inevitably resulted in the decrease of arable and grazing land, reduced production of crops, meat, and milk products, and reduced income for the local farmers. If no measures to conserve the natural resources are implemented in the near future, the increase in soil deterioration will continue. Land scarcity will follow with related conflicts between the users, food insecurity, and poverty.

The generation of an environmental database and the mapping of LULC and existing soil degradation are the bases for improved natural resource management. Detailed surveys are therefore recommended to intensify the land use inventory to generate an environmental database in Nigeria. This would include information on present LULC and the extent of soil degradation.

Land use plans should also be developed illustrating the areas used for agriculture (farming and pasturing), urban development, industry, and commercial purpose. Information of these kinds are a useful tool for policymakers and land use planners and would contribute to an enhanced management of the environment in Nigeria and Bénin.

Azeza, M.I. and M.U. Omeje. 1985. Soil erosion control measures in the Sahel. In Proceedings of Conference National Workshop on Ecological Disasters in Nigeria: Drought and Desertification. 9–12 December 1985. Kano, Nigeria. pp. 377–379.

Eswaran, H., R. Lal, and P.F. Reich. 2001. Land degradation: an overview. In Responses to Land Degradation, edited by E.M. Bridges, I.D. Hannam, L.R. Oldeman, F.W.T. Pening de Vries, S.J. Scherr, and S. Sompatpanit. Proceedings of the 2nd International Conference on Land Degradation and Desertification, Khon Kaen, January 1999. New Delhi: Oxford Press.
FAO, AGL. 2005. Global Assessment of the Status of Human-Induced Soil Degradation (GLASOD).

FRN (Federal Republic of Nigeria). 2007. Official Gazette: Legal Notice on publication of the details of the breakdown of the National and State provisional totals 2006 Census. Government Notice Nr. 21. Nr. 24. Vol. 94. Lagos.

Igbozurike, U.M., D.U.U. Okali, and A.T. Salau. 1989. Profile on Nigeria: Land Degradation. Report submitted to Commonwealth Secretariat, London. Friedrich Ebert Foundation, Lagos, and Nigerian Environmental Study/Action Team (NEST), Ibadan, 48 pp.

Junge, B. 2004. Die Boeden des oberen Oueme-Einzugsgebietes in Benin/Westafrika – Pedologie, Klassifizierung, Nutzung und Degradierung. PhD dissertation, University of Bonn, Germany. 291 pp.

Junge B., T. Alabi, K. Sonder, M.Subash, R. Abaidoo, D. Chikoye, and K. Stahr. 2009. Use of remote sensing and GIS for monitoring changes of land use/land cover and environmental degradation in different agroecological zones of West Africa. Int. J. Remote Sensing. (in press)
Lal, R. 1995. Sustainable management of soil resources in the humid tropics. United Nations University Press. New York, USA. 593 pp.

Lal, R. 2001. Soil Degradation by Erosion. Land Degradation and Development 12:519–539.
Odihi, J. 2003. Deforestation in afforestation priority zone in Sudano-Sahelian Nigeria. Applied Geography 23(4):227–259.

Odunze A.C. 2003. Northern Guinea savanna of Nigeria and rainfall properties for erosion control. African Soils 33:73–116.

Okoro, S.P.A. 1990. Status of forest resources of Nigeria. Paper presented at the 20th Annual Conference of the Forestry Association of Nigeria. 25–30 November 1990, Katsina, Nigeria. Forestry Association of Nigeria. 20 pp.

Ologe, K.O. 1978. A quick preliminary survey of soil erosion in northwestern Nigeria. Report for the Land Resource Division of the Federal Department of Agriculture, Kaduna. 18 pp.

Oluseyi, F.O. 2002. Integration of remote sensing data and field models of in-situ data in a GIS for environmental sensivity index mapping; a Nigerian example. Available online at: (accessed 28 July 2008).

Omo-Irabo, O.O. and K. Odunyemi. 2007. A hybrid image classification approach for the systematic analysis of land cover (LC) changes in the Niger Delta Region. Available online at: (accessed 27 July 2008).

Stamp, L.D. 1938. Land utilization and soil erosion in Nigeria. Geographical Review 28:32–45.
Tappan, G. and M. Cushing. 2004. Use of SCL-Off Landat image data for monitoring land use/ land cover trends in West Africa. USGS EROS Data Center, Sioux Falls, SD, USA. 11 pp.