Evaluation of Options for Minimizing Greenhouse Gas Emissions Through Improved Manure Management in Smallholder Dairy Farm Systems in Nandi County, Kenya
Abstract
An increase in atmospheric greenhouse gas (GHG) concentrations, mainly methane (CH4), carbon
dioxide (CO2) and nitrous oxide (N2O) from agricultural activities, is a global concern as it leads
to climate change. There is also a problem with nutrient mining, especially of nitrogen in
smallholder farms. Human population growth and increased demand for livestock products,
including milk, are expected to intensify the dairy sector which would lead to higher GHG
emissions and low availability of nutrients in farms leading to low productivity. The main objective
of this study was to develop options for minimizing nutrient losses and greenhouse gas emissions
through improved manure management in smallholder dairy farm systems in Nandi County,
Kenya. This study applied a transdisciplinary approach focusing on minimizing GHG emissions
and nutrient losses through improved manure management of smallholder dairy farmers.
Beginning with household survey followed up by Focus Group Discussions and finally validated
with Key Informant Interviews. This study found that Nandi County has three livestock
confinement systems of Only Fence (90%), Fence and Roof (2.5%) and Fence, Roof and Floor
(7.5%). The study also observed seven manure management systems; heaping fresh manure (49%),
heaping dry manure (44%), biogas (2.7%), slurry (2.7%), splitting urine (0.3%), compost (0.3%)
and storing urine (0.3%). It was observed that 94% of manure was managed as uncovered heaps
of either fresh or dry manure. Manure stored in such manner lost about 50% of N during a threemonth
storage experiment; the N lost is substantial. The study analysed and found GHG (CH4,
CO2, and N2O) emissions from uncovered solid storage manure heaps have the highest emissions
from Fence, Roof, and Floor as the manure from Only Fence systems have already lost most of
the urine N through leaching. In terms of GHG (CH4, CO2, and N2O) emissions converted to
Global Warming Potential for comparison, manure from FRF managed as solid storage emitted
the highest contribution (37%). Solid storage of manure yielded mean methane conversion factor
(0.043%) and mean emission factor for N2O (0.003%). The key technical socio-economic and
institutional constraints to improving manure management were that smallholder dairy farmers
had a low opinion of using manure from their farms on high-value crops. These farmers also had
a low opinion on the need to improve manure quality in terms of handling, storage, and application
due to a lack of available farm labour. This study shows that dairy cattle manure is valued highly
by the farmers and shows that a critical source of information for improving manure management
is local radio. This study observed that majority of the farmers had received information on manure
management within the last five years. The farmers in this study preferred heaping either fresh or
dry manure as it was the least labour intensive way to manage manure produced from the various
animal confinements. The general conclusion of this study is that smallholder farmers in Nandi
County, like many other smallholder farmers, have diversified farm activities and are willing to
improve manure management after being informed of the losses. This study recommends the
engagement of institutions focusing on dairy agriculture, industry, traders, and farmers. This
engagement is to explore ways to incentivize or lower costs for robust manure management
systems such as biogas systems that would be more effective in minimizing N losses while
mitigating GHG emissions.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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