Dr. Bernard Vanlauwe
Dr. Bernard Vanlauwe on the benefits of integrated soil fertility management and the state of soil nutrition in Africa
IFA: You are a leading world expert on Integrated Soil Fertility Management (ISFM) – can you tell us more about it and its benefits?
Dr. Bernard Vanlauwe: Integrated Soil Fertility Management (ISFM) is the result of 30 years of agronomy research in Africa. The core principles are based on doing all the right agronomic practices to ensure that applied nutrient inputs are used as efficiently as possible. To do this you need both a good supply of, and demand for, nutrients.
To ensure a good nutrient supply you need to use mineral fertilizers and the the 4Rs – applying the Right nutrient sources, at the Right rate, at the Right time and in the Right place. Beside that you also need organic resources to help produce optimum soil health. On the demand side you need good seeds alongside good agronomic practices, such as planting and weeding at the right time.
A second dimension is local adaptation. There is huge variability between fields within a single farm and between farms within a specific farming community for diverse reasons, partly natural and partly the result of differential management practices. This affects responses to applied nutrient inputs so it’s necessary to adapt ISFM to these conditions.
ISFM is about maximizing nutrient use efficiency, thus minimizing nutrient losses and maximizing yields and farmers’ net incomes by offering a good return on investment.
IFA: What more can the fertilizer industry and farmers do to adopt the combined use of mineral and organic fertilizers as part of ISFM?
Dr. Bernard Vanlauwe: Talking specifically about smallholder farmers in Africa, those who currently use mineral fertilizers are often not sure exactly what is in the products. In addition, they usually don’t know what fertilizer is best for each crop and the makeup of the soil they are working with.
It would be good to ensure that farmers are supplied with more information about the fertilizers they are using and to focus more on soil and plant diagnostics. In some cases, more appropriate fertilizers for specific crops are needed, for example DAP is not really suited as a top-dressing fertilizer to cassava. While the 4Rs are great in principal, it’s important to make sure that they translate into practice as well and implemented in the broader ISFM framework to be sure that a good supply of nutrients is met by an equally high demand for those nutrients.
For most smallholders in Africa there are only really two sources of organic resources: compost/manure and crop residues. In areas with absence of natural fallows, both of these are in short supply because yields are low, and the residues are used for other things. This is usually the case in areas with lots of people living in small areas of land, such as the Ethiopian Highlands, parts of Northern Nigeria, or the Central African Great Lakes Region.
To kickstart ISFM in Africa mineral fertilizers are needed first, rather than the other way around. Mineral fertilizers are needed to increase yields to three ton of maize per hectare or more and thus generate organic inputs through crop residues. Agroforestry could also help as well as the integration of grain legumes, provided they fit into existing food systems.
IFA: What is the current state of soil nutrition and fertility in Central Africa and how can it be improved?
Dr. Bernard Vanlauwe: The Central Africa Hub (CAH) covers the entire Congo basin region. It’s a big area with a lot of diversity in agro-ecological conditions. There are a wide variety of very different cropping systems from cassava and maize to sorghum and millet, and even banana.
The CAH currently has the lowest rates of fertilizer use in Africa apart from Rwanda. Burundi is investing in fertilizer use as they are aware of its importance for improving productivity, and it’s being used for cocoa and coffee in Cameroon, but the rates still remain far behind other regions. Fertilizer access needs to be increased and the 4Rs taught in the context of ISFM.
Soil quality again varies from region to region and according to production methods. In high population areas that continue to practice slash and burn, agriculture is more intensive near the roads and houses and continues up to the primary forest, so soil nutrient decline happens where production is more intensive near homes.
On the other hand, in the highlands where there is high population density the best soils are near houses because that is where all the organic fertilizer is being applied through nutrient recycling. As you move further away from them the degradation increases.
IFA: Can you tell us about some of your current and upcoming research and development projects?
Dr. Bernard Vanlauwe: We run a number of different projects. The African Cassava Agronomy Initiative (ACAI), for example, is aiming at developing and disseminating a set of decision support tools for improving cassava root quality and yields and fresh root supply to the processing sector. We also run similar projects for bananas, grain legumes and maize.
Such projects are designed to provide the necessary information and generate the tools to put ISFM into practice. These and other projects also contain components to scale up this information and these tools with close participation of public and private extension partners.
About Dr. Bernard Vanlauwe
Bernard Vanlauwe has led the Central Africa Hub and the Natural Resource Management research area at the International Institute of Tropical Agriculture (IITA) since 2012. Previously, he was the leader of the Integrated Soil Fertility Management (ISFM) program of the Tropical Soil Biology and Fertility research area of CIAT (TSBF). He joined CIAT-TSBF in 2001 and led the development, adaptation, and dissemination of best ISFM options in various agroecological zones in sub-Saharan Africa.
For more insights from Dr. Vanlauwe into ISFM in Africa watch IFA’s interview with him here.
About Integrated Mineral and Organic Fertilizer Use
To read more about ISFM and the integrated use of mineral and organic fertilizer, have a look at IFA’s new policy paper on integrated plant nutrient management here.