Tropentag, September 17 - 19, 2018 in Ghent "Global food security and food safety: The role of universities"

Improved Greenhouse Gas Emissions and Nutrient Losses Estimates from Manure of Kenyan Smallholder Dairy Farmers

¹Kenya Forestry Research Institute, Turkana Forestry Research Sub-Centre, Kenya
²Science and Technology Branch, Agriculture and Agri-Food Canada, Canada
³International Livestock Research Institute (ILRI), Livestock Syst. and Envir., Kenya
⁴Wageningen University and Research, Dept. of Animal Sciences, The Netherlands
⁵University of Nairobi, Institute for Climate Change Adaptation, Kenya
⁶University of Nairobi, Department of Geology, Kenya
⁷Lancaster University, Lancaster Environment Centre, United Kingdom

Abstract

African agriculture produces 15% of the global agricultural greenhouse gas (GHG) emissions, with 25% of these GHG emissions from the African continent attributed to manure and manure management. To date few studies are available that focus on manure management within smallholder dairy farming systems and the subsequent GHG emission estimates. There is need to improve GHG inventories in sub-Saharan African (SSA) countries. The study region was located in Western Kenya and prior to data collection stratified into three Agro-Ecological Zones (AEZs). From the zones, we identified animal confinement systems, main manure management systems and duration of storage of manure. CH₄ and N₂O emissions from manure management were then estimated for the region using both Tier 1 and Tier 2 IPCC guidelines. GHG flux measurements from manure piles that were collected from the animal confinements previously characterised, were carried out using non-flow through, non-steady state GHG chambers. Measurements lasted for a period of 90 days. Leachate was collected daily via an inbuilt drainage tube with solid manure sampled from the heaps periodically. Annual CH₄ and N₂O emissions from manure management systems in Nandi County using Tier 1 were 0.22 Gg CH₄ yr^-1, 0.16 Gg N₂O yr^-1 and categorization of manure management systems for SSA leads to lower Bo and hence lower MCF and lower Tier 2 CH4 emissions (0.002 Gg CH₄ yr^-1 and 0.031 Gg N₂O yr^-1) than Tier1. Methane emission factors from manure management were higher using the Tier 2 the currently than Tier 1. The confinement systems “Fence Only”, “Fence and Roof” and “Fence, Roof and Floor had significant differences in cumulative CH₄ but not for cumulative N₂O emissions. Mean nitrogen (N) lost from the manure through leaching ranged from 2.0 g N to 2.1 g N. This study provides a mechanism to improve Tier 2 GHG emission calculations for manure management in smallholder farming systems in SSA that could help identify practices to reduce GHG emissions originating from agriculture. The over 40% loss of nutrient N from manure provides for further justification on the need to improve manure management for smallholder farmers. Furthermore, improved manure management allows smallholder farmers to benefit from the manure are fertiliser by returning essential nutrients to the soil.

Keywords: Dairy, East Africa, greenhouse gases, manure, smallholder

Contact Address: Jesse Owino, Kenya Forestry Research Institute, Turkana Forestry Research Sub-Centre, P.O. Box 53, 30500 Lodwar, Kenya, e-mail: owinojessegmail.com