DOI: 10.5285/024c5a61-5114-41a6-93b8-e3fb4d24622b
title: Biophysical measurements from Ethiopia's Awassa region during the drought and subsequent floods of 2015-2016

description: This dataset contains the biophysical measurements (mineral nitrogen, percent carbon, percent nitrogen, percent soil moisture, particle size analysis and aggregate stability) from soil collected from farmers' fields in the Halaba district, Southern Nations, Nationalities and Peoples' Region in Ethiopia, after the drought of 2015-2016. Eighteen farms from four kebeles (Asore, Lay Arisho, Konicha and 1st Choroko) were sampled. Soil cores were taken from fields classed as "home", "near" and "far" from the homestead and were taken from two depths (0-20cm and 20-50cm). Soil cores were taken after the El Niño event of 2015/16, so reflect the resilience of different areas of the farm to drought. This dataset was collected as part of the NERC-funded project Building Resilience in Ethiopia's Awassa region to Drought (BREAD).
description: The biophysical measurements were collected from farmers' fields in Halaba District near Hawassa (SNPPR, Ethiopia), after the drought of 2015-2016. Combined with the data provided by the ALTER project (deposited on the EIDC), this provides measurements of soil carbon (C), nitrogen (N) and water characteristics before and after the drought.

Soil cores were collected from fields classed as "home", "near" and "far" from the homestead. This corresponds to fields at increasing distance from the household, but does not equate to a set distance; it is more a reflection of the typical land uses in the fields.

Measurements are provided at the surface (0-20cm) and below the plough layer (20-50cm). Measurements were collected from fields belonging to farmers with different wealth status (poor medium and rich) in four kebeles (parishes); Eighteen farms were sampled in each kebele.

Percent N and percent C in the soil were measured by CNS elemental analyser, Soil pH was measured using a pH meter, 1:5 in CaCl2.

Mineral N measurements include nitrate, nitrite and ammonium in μmol per g soil. Nitrate and nitrite were determined by measuring absorbance over a period of 5 hours at a wavelength of 540nm. Ammonium was determined using the indophenol method by measuring absorbance for 30 minutes using a 620 nm wavelength.

Soil moisture measurements include the soil moisture content when sampled and at -10 kPa (% by weight). It was not possible to obtain intact cores from Ethiopia or to conduct analysis in country due to equipment availability. Therefore, disturbed soil was repacked into collars and soils were saturated for 48 hours (some were hydrophobic) and then dried to -10 kPa matric potential using a tension table. This potential was selected to represent field capacity due to the sandy nature of this soil.

Particle size and aggregate stability were measured for Asore and Lay Arisho only. The percent silt, sand and clay were determined by Laser-diffraction analysis (LDA). Aggregate stability was determined following the wet-sieving method. Bulk density measurements were not taken. However, pedotransfer functions have been derived from the ALTER measurements that allow bulk density to be determined from soil texture and C content.