Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Smallholder farms in eastern African tropical highlands have low soil greenhouse gas fluxes. / Pelster, David; Rufino, Mariana; Rosenstock, Todd et al.
In: Biogeosciences, Vol. 14, No. 1, 12.01.2017, p. 187-202.Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Smallholder farms in eastern African tropical highlands have low soil greenhouse gas fluxes
AU - Pelster, David
AU - Rufino, Mariana
AU - Rosenstock, Todd
AU - Mango, Joash
AU - Saiz, Gustavo
AU - Diaz-Pines, Eugenio
AU - Baldi, German
AU - Butterbach-Bahl, Klaus
PY - 2017/1/12
Y1 - 2017/1/12
N2 - Few field studies examine greenhouse gas (GHG) emissions from African agricultural systems, resulting in high uncertainty for national inventories. This lack of data is particularly noticeable in smallholder farms in sub-Saharan Africa, where low inputs are often correlated with low yields, often resulting in food insecurity as well. We provide the most comprehensive study in Africa to date, examining annual soil CO2, CH4 and N2O emissions from 59 smallholder plots across different vegetation types, field types and land classes in western Kenya. The study area consists of a lowland area (approximately 1200ma.s.l.) rising approximately 600m to a highland plateau. Cumulative annual fluxes ranged from2.8 to 15.0MgCO2-Cha-1,-6.0 to 2.4kgCH4-Cha-1 and-0.1 to 1.8kgN2O-Nha-1. Management intensity of the plots did not result in differences in annual GHG fluxes measured (P Combining double low line 0.46, 0.14 and 0.67 for CO2, CH4 and N2O respectively). The similar emissions were likely related to low fertilizer input rates (≤20kgNha-1). Grazing plots had the highest CO2 fluxes (P Combining double low line 0.005), treed plots (plantations) were a larger CH4 sink than grazing plots (P Combining double low line 0.05), while soil N2O emissions were similar across vegetation types (P Combining double low line 0.59). This study is likely representative for low fertilizer input, smallholder systems across sub-Saharan Africa, providing critical data for estimating regional or continental GHG inventories. Low crop yields, likely due to low fertilization inputs, resulted in high (up to 67gN2O-Nkg-1 aboveground N uptake) yield-scaled emissions. Improvement of crop production through better water and nutrient management might therefore be an important tool in increasing food security in the region while reducing the climate footprint per unit of food produced.
AB - Few field studies examine greenhouse gas (GHG) emissions from African agricultural systems, resulting in high uncertainty for national inventories. This lack of data is particularly noticeable in smallholder farms in sub-Saharan Africa, where low inputs are often correlated with low yields, often resulting in food insecurity as well. We provide the most comprehensive study in Africa to date, examining annual soil CO2, CH4 and N2O emissions from 59 smallholder plots across different vegetation types, field types and land classes in western Kenya. The study area consists of a lowland area (approximately 1200ma.s.l.) rising approximately 600m to a highland plateau. Cumulative annual fluxes ranged from2.8 to 15.0MgCO2-Cha-1,-6.0 to 2.4kgCH4-Cha-1 and-0.1 to 1.8kgN2O-Nha-1. Management intensity of the plots did not result in differences in annual GHG fluxes measured (P Combining double low line 0.46, 0.14 and 0.67 for CO2, CH4 and N2O respectively). The similar emissions were likely related to low fertilizer input rates (≤20kgNha-1). Grazing plots had the highest CO2 fluxes (P Combining double low line 0.005), treed plots (plantations) were a larger CH4 sink than grazing plots (P Combining double low line 0.05), while soil N2O emissions were similar across vegetation types (P Combining double low line 0.59). This study is likely representative for low fertilizer input, smallholder systems across sub-Saharan Africa, providing critical data for estimating regional or continental GHG inventories. Low crop yields, likely due to low fertilization inputs, resulted in high (up to 67gN2O-Nkg-1 aboveground N uptake) yield-scaled emissions. Improvement of crop production through better water and nutrient management might therefore be an important tool in increasing food security in the region while reducing the climate footprint per unit of food produced.
U2 - 10.5194/bg-14-187-2017
DO - 10.5194/bg-14-187-2017
M3 - Journal article
AN - SCOPUS:85009499739
VL - 14
SP - 187
EP - 202
JO - Biogeosciences
JF - Biogeosciences
SN - 1726-4170
IS - 1
ER -