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Spatial and temporal variation of soil nutrient stocks and management in Sub-Saharan African farming systems

Objective

The main objective is:
* To study variation in space and time of soil nutrient stocks at farm level, the possible role of integrated nutrient management systems in reversing present trends of nutrient depletion, and the aggregation of farm-level data to higher administrative and policy levels in two major, but contrasting ecoregions in sub-Saharan Africa, i.e. the East African Highlands and the West African Savannas.
Specific objectives include:
* To measure natural and man-induced spatial variation of soil nutrient stocks (C, N, P, K, Ca, Mg, pH, CEC), soil physical properties and microclimate at farm level.
* To measure and estimate the major nutrient flows at farm level.
* To study, compare and classify prevailing farm management and INM, including increased and 'spatially and temporally-tailored' use of mineral fertilizers and amendments (rock phosphates, lime), crop livestock interactions, and the utilisation of on-farm and off-farm organic inputs.
* To develop guidelines to aggregate obtained research data to district and higher policy levels; determine the implications for the predictive value of point models.
* To organize workshops and field days for the different stakeholders in agriculture and natural resource management, and to publish research results in (inter)national journals and at conferences.
Expected Outcome

The work carried out in this project should provide a quantitative picture of soil fertility levels and spatial and temporal trends in two dominant, but highly contrasting agro-ecozones in Africa. Next, it will yield information on the agronomic value of certain technologies aimed at maintenance and improvement of soil productivity. It will also provide clues to tackle some methodological constraints in the field of error build-up and upscaling results from points to plots and from farms to districts.
Lastly, bottom-up involvement of farm households and other stakeholders will create maximum sense of ownership of project progress and results, and may strongly enhance farmer-to-farmer and district to-district dissemination.
The key activities envisaged are:
* On the basis of a participatory survey of the farms (farm family indicates plots, crops and other activities, and soil fertility differences), a soil fertility sampling strategy will be developed and implemented.
* On the basis of participatory monitoring of farm nutrient management (farm family indicates manjor nutrient flows), the most manageable and recognizable flows will be quantified (fertilizers, manure, harvested products, crop residues, but also leaching), whereas less obvious and 'hard-to-measure' flows will be estimated (atmospheric deposition, nitrogen fixation, gaseous losses, erosion).
* On the basis of farmers' preferences, the quantitative impact of three integrated nutrient management technologies will be studied; likely examples are composting, crop-livestock interactions, rock phosphates mixed with manure, etc.
* As a nutrient balance is made up of many variables, problems related to aggregation and error propagation will be studied. Also, problems inherent to the upscaling of point data to plots and farms, and farm data to watersheds and districts will be addressed. Different mathematical and statistical approaches will be employed and compared.
* Interaction with stakeholders will take place through direct individual and group interactions, and through workshops and conferences. Written results will be covered in leaflets and scientific papers.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Dienst Landbouwkundig Onderzoek
Address
11/22,Marijkeweg
6700 AC Wageningen
Netherlands

Participants (4)

Centre de Coopération Internationale en Recherche Agronomique pour le Développement - CIRAD
France
Address
2477,Rue Du Val De Montferrand
34032 Montpellier
Institut National d'Etudes et de Recherches Agricoles du Burkina-Faso
Burkina Faso
Address

01 Ouagadougou
KENYA AGRICULTURAL RESEARCH INSTITUTE
Kenya
Address
Waiyaki Way
2 Nairobi
NATIONAL AGRICULTURAL RESEARCH FOUNDATION
Greece
Address
1,Theophrastou Street 1
413 35 Larisa