Nitrous Oxide Emissions from Smallholders’ Cropping Systems in Sub-Saharan Africa

Lemarpe, Shaankua E.; Musafiri, Collins M.; Macharia, Joseph M.; Kiboi, Milka N.; Ng’etich, Onesmus K.; Shisanya, C.A.; Okeyo, Jeremiah M.; Okwuosa, Elizabeth A.; Ngetich, Felix K.

doi:10.1155/2021/4800527

Cited by 3 publications

(1 citation statement)

References 82 publications

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“…As most agriculture in SSA is rainfed and uses low inputs, GHG emissions and yields remain low (Nyiwul 2021). However, the intensification and expansion of agricultural land in sub-Saharan Africa can be expected; hence, studies show consistent projections of how much it might cost in terms of GHG emissions to reduce yield gaps in the region, in particular nitrous oxide (N 2 O) emissions (Leitner et al 2020, Lemarpe et al 2021. According to Omotoso and Omotayo (2024), 64% of total N 2 O emissions during 2020 in SSA came from agricultural soils.…”

Section: Introductionmentioning

confidence: 99%

Agro-technology for climate-smart agriculture and resilience to climate extremes in sub-Saharan Africa

Arenas-Calle,

Jennings,

Challinor

2024

Environ. Res.: Food Syst.

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Agro-technologies such as irrigation and new crop varieties can reduce climate risk for agricultural production in Sub-Sahara Africa. SSA has the highest maize yield gaps globally, despite its importance as a staple crop in the region. Reducing maize yield gaps is key to tackling food insecurity; however, closing yield gaps has an environmental cost. Climate-smart agriculture (CSA) seeks to minimise this cost whilst maximising productivity and resilience. One key element of CSA is resilience to extreme events, although this is rarely examined. Accordingly, we assess the climate smartness of contrasting agro-technology and climate scenarios to assess both reslience to extremes and the overall climate smartness of the scenarios. We use simulations from an existing integrated modelling framework for Malawi, Tanzania, and Zambia, centred on 2050. Four scenarios were examined, defined by combinations of high vs. low agro-technology adoption and high vs. low climate risk (RCP2.6 and RCP8.5). We calculated a Climate Smartness Index (CSI) to the model outputs that quantify the trade-offs between greenhouse gas emissions and agricultural productivity. CSI scores showed that the increase in GHG emissions from improved agro-technology is compensated for the yield benefits. Agro-technology in SSA can therefore benefit the pillars of climate-smart agriculture, namely increased mitigation, adaptation, and productivity. Further, we show that improved maize varieties and irrigation can substantially reduce future yield shocks and enhance resilience to climate change extremes in SSA, pointing to best-bets for agro-technology adoption. Irrigation reduces mid-century yield shocks by 64% (RCP2.6) or 42% (RCP8.5). When combined with improved maize varieties, irrigation removes the majority of yield shocks (90%) in RCP8.5. We therefore conclude that: i. irrigation has significant potential to increase resilience in SSA; and ii. Investment in strategies to improve crop varieties is critical if the benefits or irrigation are to be fully realized under an RCP8.5 future.

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Section: Introductionmentioning

confidence: 99%

Agro-technology for climate-smart agriculture and resilience to climate extremes in sub-Saharan Africa

Arenas-Calle,

Jennings,

Challinor

2024

Environ. Res.: Food Syst.

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Soil greenhouse gas emissions from different land utilization types in Western Kenya

Kibet¹,

Musafiri²,

Kiboi³

et al. 2022

Front. Soil Sci.

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IntroductionThere is a vast data gap for the national and regional greenhouse gas (GHG) budget from different smallholder land utilization types in Kenya and sub-Saharan Africa (SSA) at large. Quantifying soil GHG, i.e., methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) emissions from smallholder land utilization types, is essential in filling the data gap.MethodsWe quantified soil GHG emissions from different land utilization types in Western Kenya. We conducted a 26-soil GHG sampling campaign from the different land utilization types. The five land utilization types include 1) agroforestry M (agroforestry Markhamia lutea and sorghum), 2) sole sorghum (sorghum monocrop), 3) agroforestry L (Sorghum and Leucaena leucocephala), 4) sole maize (maize monocrop), and 5) grazing land.Results and discussionThe soil GHG fluxes varied across the land utilization types for all three GHGs (p ≤ 0.0001). We observed the lowest CH4 uptake under grazing land (−0.35 kg CH4–C ha−1) and the highest under sole maize (−1.05 kg CH4–C ha−1). We recorded the lowest soil CO2 emissions under sole maize at 6,509.86 kg CO2–Cha−1 and the highest under grazing land at 14,400.75 kg CO2–Cha−1. The results showed the lowest soil N2O fluxes under grazing land at 0.69 kg N2O–N ha−1 and the highest under agroforestry L at 2.48 kg N2O–N ha−1. The main drivers of soil GHG fluxes were soil bulk density, soil organic carbon, soil moisture, clay content, and root production. The yield-scale N2O fluxes ranged from 0.35 g N2O–N kg−1 under sole maize to 4.90 g N2O–N kg−1 grain yields under agroforestry L. Nevertheless, our findings on the influence of land utilization types on soil GHG fluxes and yield-scaled N2O emissions are within previous studies in SSA, including Kenya, thus fundamental in filling the national and regional data of emissions budget. The findings are pivotal to policymakers in developing low-carbon development across land utilization types for smallholders farming systems.

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Fertilizers for food and nutrition security in sub-Saharan Africa: An overview of soil health implications

et al. 2023

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Sub-Saharan Africa (SSA) faces chronic food insecurity associated with soil degradation and the peculiar aftermath of climate change and exacerbated by rising population and historically poor agricultural practices. Notably, use of mineral fertilizers has the potential to counteract soil degradation in SSA; it drives an increased agricultural production required to feed the rising population while sustaining the quality and health of soils. However, limited financial resources deprive SSA of the promise of fertilizers, wherein application rates are historically low, and regimes are characterized by unbalanced nutrient composition and poor fertilizer quality. Although current global fertilizer use is generally characterized by low efficiency, SSA is most affected due to the already low usage and the quality of available fertilizer products. About 70% of fertilizer-nitrogen is lost through unregulated transformation to ammonia, nitrous oxide, and nitrate that are either volatilized or emitted into the atmosphere or leached into water bodies. Similarly, the preponderance of fertilizer-phosphorus is lost via run-off and leaching, unavailing it to plants while overloading streams and rivers and, together with nitrate, causing eutrophication. These environmental problems are accentuated in SSA where fertilizer quantity and quality issues are already a limiting factor. Notably, recent advances happening outside of SSA indicate that nutrients, when strategically formulated, such as by nano packaging, (bio)polymer encapsulation, and tunable to respond to environmental cues, can provide multiple outcomes, particularly, healthy soils with higher productivity. Therefore, presumably, a proper synthesis of the gamut of soil properties influencing plant nutrient release and availability, options for plant exposure and uptake is critical for realizing these benefits in SSA. Despite these possibilities, there is a lack of deeper context on fertilizer-related issues as they affect food and nutrition security and the health of soils in SSA. This paper provides an overview of the fertilizer-nutrient and associated agronomic, food insecurity and soil environmental challenges and opportunities, which though not exclusive to SSA per se, can be reasoned with the peculiarity of the region. This provides the impetus to increase fertilizer use efficiency, improve soil and environmental health, sustainable crop production, and food and nutrition security in SSA.

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Nitrous Oxide Emissions from Smallholders’ Cropping Systems in Sub-Saharan Africa

Cited by 3 publications

References 82 publications

Agro-technology for climate-smart agriculture and resilience to climate extremes in sub-Saharan Africa

Agro-technology for climate-smart agriculture and resilience to climate extremes in sub-Saharan Africa

Soil greenhouse gas emissions from different land utilization types in Western Kenya

Fertilizers for food and nutrition security in sub-Saharan Africa: An overview of soil health implications

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