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P. Smith  - - - 
Top co-authors See all
S. J. Welham

34 shared publications

Biomathematics & Bioinformatics, Rothamsted Research, Harpenden, AL5 2JQ, UK

P.D. Hallett

29 shared publications

School of Biological Sciences, University of Aberdeen, Aberdeen, UK

Kevin Coleman

25 shared publications

Rothamsted Research

Klaus Glenk

20 shared publications

Land Economy Unit, Scottish Rural College. Edinburgh, United Kingdom

Mark Pogson

19 shared publications

Department of Applied Mathematics, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, United Kingdom

Publication Record
Distribution of Articles published per year 
(1996 - 2018)
Total number of journals
published in
Publications See all
Article 0 Reads 0 Citations Tropical wetland ecosystem service assessments in East Africa; A review of approaches and challenges Charlie Langan, Jenny Farmer, Mike Rivington, Jo U. Smith Published: 01 April 2018
Environmental Modelling & Software, doi: 10.1016/j.envsoft.2018.01.022
DOI See at publisher website
Article 0 Reads 0 Citations Are smallholder farmers willing to pay for a flexible balloon biogas digester? Evidence from a case study in Uganda Moris Kabyanga, Bedru B. Balana, Johnny Mugisha, Peter N. Wa... Published: 01 April 2018
Energy for Sustainable Development, doi: 10.1016/j.esd.2018.01.008
DOI See at publisher website
Article 0 Reads 1 Citation Household energy and recycling of nutrients and carbon to the soil in integrated crop-livestock farming systems: a case ... Dugassa Negash, Assefa Abegaz, Jo U. Smith, Hailu Araya, Bog... Published: 28 June 2017
GCB Bioenergy, doi: 10.1111/gcbb.12459
DOI See at publisher website
ABS Show/hide abstract
Soil amendment with organic wastes in the Highlands of Ethiopia has been greatly reduced by widespread use of dung cakes and crop residues as fuels. This study assessed the interaction between household energy and recycling of nutrients and carbon to the soil using household survey, focus group discussions, key informant interviews, direct observations and measurements between 2014 and 2015 in Kumbursa village (Central Highlands of Ethiopia). All surveyed households were entirely dependent on biomass fuel for cooking, with production and consumption rates directly related to wealth status, which significantly varied (P < 0.001) among three farm wealth groups (poor, medium and rich). Crop residues and dung cakes accounted for 80(±3)% by energy content and 85(±4)% by dry mass weight of total biomass fuel consumption. Mean losses were 59(±2) kg ha−1 yr−1 nitrogen (109(±8) kg yr−1 per household), 13.9(±0.3) kg ha−1 yr−1 phosphorus (26(±2) kg yr−1 per household), 79(±2) kg ha−1 yr−1 potassium (150(±11) kg yr−1 per household) and 2100(±40) kg ha−1 yr−1 organic carbon (3000(±300) kg yr−1 per household). Rich farmers lost significantly more carbon and nutrients in fuel than farmers in other wealth groups. However, these losses were spread over a larger area, so losses per land area were significantly higher for medium and poor than for rich farmers. This means that the land of poorer farmers is likely to become degraded more rapidly due to fuel limitations than that of rich farmers, so increasing the poverty gap. The estimated financial loss per household due to not using dung and crop residues as organic fertilizer was 162(±8) US$ yr−1. However, this is less than their value as fuels, which was 490(±20) US$ yr−1. Therefore, farmers will only be persuaded to use these valuable assets as soil improvers if an alternative, cheaper fuel source can be found.
Article 0 Reads 0 Citations Water for small-scale biogas digesters in Sub-Saharan Africa Vamini Bansal, Vianney Tumwesige, Jo U. Smith Published: 02 May 2016
GCB Bioenergy, doi: 10.1111/gcbb.12339
DOI See at publisher website
ABS Show/hide abstract
Biogas could provide a more sustainable energy source than woodfuels for rural households in Sub-Saharan African. However, functioning of biogas digesters can be limited in areas of low water availability. The water required is approximately 50 dm3 day−1 for each cow and 10 dm3 day−1 for each pig providing manure to the digester, or 25 (±6) dm3 day−1 for each person in the household, using a digester volume of 1.3 (±0.3) m3 capita−1. Here we consider the potential of domestic water recycling, rainwater harvesting and aquaculture to supply the water needed for digestion in different countries of Sub-Saharan Africa. Domestic water recycling was found to be important in every country but was usually insufficient to meet the requirements of the digester, with households in 72% of countries needing to collect additional water. Rooftop rainwater harvesting also has an important role, iron roofs being more effective than thatched roofs at collecting water. However, even with an iron roof, the size of roof commonly found in Sub-Saharan Africa (15 m2 to 40 m2) is too small to collect sufficient water, requiring an extra area (in m2) for each person of (where R is the rainfall in mm). If there is a local market for fish, stocking a pond with tilapia, fed on plankton growing on bioslurry from the digester, could provide an important source of additional income and hold the water required by the digester. In areas where rainfall is low and seasonal, the fishpond might be stocked only in the rainy season, allowing the pond to be covered during the dry period to reduce evaporation. If evaporative losses (E in mm) exceed rainfall, an extra catchment area is needed to maintain the water level in the pond, equivalent to approximately m2 for each person in the household.This article is protected by copyright. All rights reserved.
Article 2 Reads 4 Citations Spatial and temporal dynamics of soil organic carbon in landscapes of the upper Blue Nile Basin of the Ethiopian Highlan... Assefa Abegaz, Leigh A. Winowiecki, Tor-G. Vågen, Simon Lang... Published: 01 February 2016
Agriculture, Ecosystems & Environment, doi: 10.1016/j.agee.2015.11.019
DOI See at publisher website
BOOK-CHAPTER 0 Reads 0 Citations Mathematical Modeling of Greenhouse Gas Emissions from Agriculture for Different End Users Jon Hillier, Mohammed Abdalla, Jessica Bellarby, Fabrizio Al... Published: 01 January 2016
Advances in Agricultural Systems Modeling, doi: 10.2134/advagricsystmodel6.2013.0038
DOI See at publisher website