A geospatial database of drought occurrence in inland valleys in Mali, Burkina Faso and Nigeria

The data described in this article are related to drought occurrence in inland valleys and farmers adaptation strategies. The data were collected in 300 inland valleys distributed in 14 regions of West Africa. The data were collected in two phases. In the first phase, 300 inland valleys were identified in 14 regions and their locations were determined with handheld GPS devices. Questionnaires and informal interviews were administered to inland valleys users to collect data on physical and socio-economic characteristics, hydrology, farmers experience with drought affecting rice production in inland valleys and adaptation strategies. In the second phase, the locations of the inland valleys were imported in a GIS environment and were used to extract additional parameters on soil characteristics and water demand from the Shuttle Radar Topography Mission (SRTM), Africa Soil Information Service (africasoils.net) and POWER database (http://power.larc.nasa.gov). In total, the dataset contains 41 variables divided into seven themes: farmers’ experience with drought, adaptive management of rice farmers to drought, physical characteristics, hydrology, management practices, socio-economic characteristics and weather data of inland valleys.

power.larc.nasa.gov). In total, the dataset contains 41 variables divided into seven themes: farmers' experience with drought, adaptive management of rice farmers to drought, physical characteristics, hydrology, management practices, socio-economic characteristics and weather data of inland valleys. & 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Environmental Sciences, Social Sciences More specific subject area Climate, Food security, Agriculture Type of data

Value of the data
Large multidisciplinary dataset comprising 300 inland valleys in 14 regions distributed in 3 countries in West-Africa, covering location, physical characteristics, socioeconomic characteristics, hydrology, weather data, farmers management practices, farmers experience with drought affecting rice production in inland valleys and adaptation strategies.
The dataset can be deployed to assess the impacts of drought on rice production, to classify farmers management approaches to mitigate drought in inland valleys, to characterize the diversity of inland valleys based on biophysical and socio-economic characteristics, to analyze suitability of inland valleys for rice-based production systems, etc.
The data can be linked to similar surveys conducted in Benin, Liberia and Sierra Leone [1][2][3] to analyze the determinants of farmers decision-making with respect to agricultural use of inland valleys in West Africa.
The dataset contributes to spatial assessment of agricultural drought and to food security research in West Africa.

Data
Inland valley ecosystems are estimated to cover 190 Mha in Africa. Inland valleys are defined as the upper parts of river drainage systems, comprising the whole upland lowland continuum, from the rainfed uplands (pluvial) to rainfed, flooded and intensified lowlands in the valley bottom (fluxial), with the hydromorphic fringes (phreatic) as the (sloping) transition zone between them [4]. Given the high agricultural production potential, inland valleys provide opportunities to improve food and  Ordinal Every year, every 2 or 3 years, every 4 or 5 years, more than every 5 years, never Survey Frequency of entire rice harvest loss Ordinal All years, in 1 to 2 years, in 3 to 6 years, in 7 to 9 years, never Survey Frequency of rice yield reduction Ordinal All years, in 1 to 2 years, in 3 to 6 years, in 7 to 9 years, never Survey nutrition security for smallholder farmer families in sub-Saharan Africa. Besides agricultural production, inland valleys provide local communities with forest, forage, hunting and fishing resources and recreational sites [1]. The database contains physical, hydrological, socioeconomic and weather data, as well as farmers experience of drought and adaptation strategies. The data were collected in 300 inland valleys distributed in 14 regions of three West African countries: Mali (98 inland valleys), Nigeria (106) and Burkina Faso (96) (see Fig. 1). The 14 regions are located in the Sudan-Sahel zone where average annual rainfall varies from 700 to 1300 mm. The inland valleys are geolocated with latitude/longitude coordinates. For each inland valley, 41 variables, grouped in seven themes (Table 1), were obtained from either farmers' responses during community surveys in inland valleys conducted in 2013 or from digital maps using the location (polygon shape file) of the inland valleys. Table 1 provides a summary of the data base and the included variables.
The data base is in Microsoft Excel format and contains eight sheets. The first sheet (variable explanation) provides an explanation of the variables. The second sheet (location) provides the unique identifier of each surveyed inland valley and the geographic coordinates expressed in longitude/latitude. The unique identifier can be linked to the variables stored in three sheets, one for each of the three countries, called Mali, Nigeria and Burkina Faso. The sheets Mali-weather data, Nigeriaweather data and Burkina Faso-weather data provide daily rainfall and minimum and maximum air temperatures from 1995 to 2014 for each surveyed inland valley.

Experimental design, materials and methods
This section provides a summary of the approaches followed to develop the geospatial data base. We refer to Dossou-Yovo et al. [5] for a full description of the methodology that was followed. Data were collected in two phases. In the first phase, 300 inland valleys were identified in 14 regions distributed in three West African countries located in the Sudan-Sahel zone, viz. Burkina Faso, Mali and Nigeria. The location of each inland valley was determined with handheld GPS devices. Data on physical and socio-economic characteristics, hydrology, farmers experience with drought in ricebased production systems and adaptation strategies were collected from small groups of 5 to 20 farmers for each inland valley based on questionnaires and informal interviews. In the second phase, the geographic locations of the inland valleys were imported in a GIS environment and their quality was checked. Spatial information available in the public domain were downloaded and imported in GIS. These included soil parameters (particle size distribution and soil organic carbon), flow accumulation, daily rainfall and minimum and maximum air temperatures data. Digital elevation data from the Shuttle Radar Topography Mission (SRTM) at a spatial resolution of 30 m were used to derive flow accumulation. Maps of soil parameters in the first 30 cm of soil depth were obtained from the Africa Soil Information Service (AfSIS) project website (africasoils.net). Gridded daily rainfall and temperature data for the period 1995-2014 were obtained from the POWER database (http://power. larc.nasa.gov/). Table 2 provides an overview of the 41 variables in the data base and their source (whether from the field surveys or public domain sources).

Funding sources
The data were collected in the framework of the project: 'Improving rice productivity in lowland ecosystems of Burkina Faso, Mali and Nigeria through marker-assisted recurrent selection for drought tolerance and yield potential' funded by the Global Challenge Programme (G7010.04.01).

Transparency document. Supplementary material
Transparency document associated with this article can be found in the online version at https:// doi.org/10.1016/j.dib.2018.06.105.