scholarly journals Decomposition characteristics of indigenous organic fertilisers and introduced quick compost and their short-term nitrogen availability in the semi-arid Ethiopian Rift Valley

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shiro Mukai ◽  
Wataru Oyanagi
Keyword(s):  
Organic Matter ◽  
Rift Valley ◽  
Nitrogen Availability ◽  
Sub Saharan Africa ◽  
Ethiopian Rift ◽  
Soluble Nitrogen ◽  
Nitrogen Mineralisation ◽  
Short Term ◽  
Analysis Methods ◽  
Organic Fertilisers

Abstract Case studies on the assessment of local organic fertilisers (OFs) in their quality (decomposition characteristics and nutrient availability for crops) are few in sub-Saharan Africa (SSA). This study assessed the quality of local OFs from the Ethiopian Rift Valley. The decomposition characteristics were assessed by acid detergent fibre analysis methods, while the short-term nitrogen availability was assessed by a combination of laboratory incubations and inorganic nitrogen and acid detergent soluble nitrogen determinations. A commercial hand-held reflectometer (RQFlex) was used for determining nitrogen components. The mean acid detergent soluble organic matter contents exceeded 250 mg g−1, indicating the OF feedstock contained much of the readily decomposable organic matter. Some of the indigenous compost (kosi) samples showed net nitrogen immobilisation during the initial period of incubation, followed by net nitrogen mineralisation in one month of incubation with 4% of the nitrogen mineralisation rate. Kosi should be applied to a field one month before seeding. Short-term nitrogen availability from kosi was too low to substitute for inorganic fertilisers. The combination of the simple analysis methods shown in this study is a quick, cost-saving, and accurate quality assessment approach for OFs, which can be useful in the field and at experimental stations in SSA.

scholarly journals Evaluation on maturity and stability of organic fertilisers in semi-arid Ethiopian Rift Valley

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shiro Mukai ◽  
Wataru Oyanagi
Keyword(s):  
Rift Valley ◽  
Field Application ◽  
Sub Saharan Africa ◽  
Site Quality ◽  
Ethiopian Rift ◽  
Weed Seeds ◽  
Probable Presence ◽  
Organic Fertilisers ◽  
Sub Saharan ◽  
Semi Arid

AbstractCase studies that have comprehensively examined local organic fertilisers (OFs) for their maturity and stability are rare in sub-Saharan Africa. Farmers in the semi-arid Ethiopian Rift Valley use indigenous compost (kosi) and household wastes for OFs. With the entry of fast compost that was introduced by the administration, maturity and stability of these OFs were assessed. Their maturity was assessed by: monitoring pile temperature and volume, pH, organic matter and total nitrogen contents, and carbon to nitrogen ratio; determination of NO3– to NH4+ ratio; and respirometric measurement of CO2 evolution. Their stability was assessed by weed seed germination tests and phytotoxicity bioassays. Weed seeds that were originally contained in the feedstock of the kosi and fast compost samples became inactive during the composting process. The CO2 evolution tests and phytotoxicity bioassays indicated a probable presence of some phytotoxic compounds in the kosi. Mature kosi and immature kosi in a kosi pile should be mixed before the field application. Some samples (15%) of the household wastes contained weed seeds. The combination of several assessment methods used in this study and determination methods for nitrogen components using RQ-flex is considered to be effective for on-site quality assessment of OFs in sub-Saharan Africa.

scholarly journals Effect of legume intercropping on N<sub>2</sub>O emissions and CH<sub>4</sub> uptake during maize production in the Great Rift Valley, Ethiopia

2020 ◽  
Vol 17 (2) ◽  
pp. 345-359
Author(s):  
Shimelis Gizachew Raji ◽  
Peter Dörsch
Keyword(s):  
Rift Valley ◽  
Crop Production ◽  
Growing Season ◽  
Maize Yield ◽  
Sub Saharan Africa ◽  
Ethiopian Rift ◽  
N2o Emissions ◽  
Mineral N ◽  
Total N ◽  
N Input

Abstract. Intercropping with legumes is an important component of climate-smart agriculture (CSA) in sub-Saharan Africa, but little is known about its effect on soil greenhouse gas (GHG) exchange. A field experiment was established at Hawassa in the Ethiopian rift valley, comparing nitrous oxide (N2O) and methane (CH4) fluxes in minerally fertilized maize (64 kg N ha−1) with and without Crotalaria (C. juncea) or lablab (L. purpureus) as intercrops over two growing seasons. To study the effect of intercropping time, intercrops were sown either 3 or 6 weeks after maize. The legumes were harvested at flowering, and half of the aboveground biomass was mulched. In the first season, cumulative N2O emissions were largest in 3-week lablab, with all other treatments being equal to or lower than the fertilized maize mono-crop. After reducing mineral N input to intercropped systems by 50 % in the second season, N2O emissions were comparable with the fully fertilized control. Maize-yield-scaled N2O emissions in the first season increased linearly with aboveground legume N yield (p=0.01), but not in the second season when early rains resulted in less legume biomass because of shading by maize. Growing-season N2O-N emission factors varied from 0.02 % to 0.25 % in 2015 and 0.11 % to 0.20 % in 2016 of the estimated total N input. Growing-season CH4 uptake ranged from 1.0 to 1.5 kg CH4-C ha−1, with no significant differences between treatments or years but setting off the N2O-associated emissions by up to 69 %. Our results suggest that leguminous intercrops may increase N2O emissions when developing large biomass in dry years but, when mulched, can replace part of the fertilizer N in normal years, thus supporting CSA goals while intensifying crop production in the region.

scholarly journals Effect of legume intercropping on N<sub>2</sub>O emission and CH<sub>4</sub> uptake during maize production in the Ethiopian Rift valley

2019 ◽  
Author(s):  
Shimelis G. Raji ◽  
Peter Dörsch
Keyword(s):  
Rift Valley ◽  
Crop Production ◽  
Growing Season ◽  
Maize Yield ◽  
Sub Saharan Africa ◽  
Ethiopian Rift ◽  
N2o Emissions ◽  
Mineral N ◽  
Total N ◽  
N Input

Abstract. Intercropping with legumes is an important component of climate smart agriculture (CSA) in sub Saharan Africa, but little is known about its effect on soil greenhouse gas (GHG) exchange. A field experiment was established at Hawassa in the Ethiopian rift valley, comparing nitrous oxide (N2O) and methane (CH4) fluxes in minerally fertilized maize (64 kg N ha−1) with and without crotalaria (C. juncea) or lablab (L. purpureus) as intercrops over two growing seasons. To study the effect of intercropping time, intercrops were sown either three or six weeks after maize. The legumes were harvested at flowering and half of the above-ground biomass was mulched. In the first season, cumulative N2O emissions were largest in 3-week lablab, with all other treatments being equal or lower than the fertilized maize monocrop. After reducing mineral N input to intercropped systems by 50 % in the second season, N2O emissions were at par with the fully fertilized control. Maize yield-scaled N2O emissions in the first season increased linearly with above-ground legume N-yield (p = 0.01), but not in the second season when early rains resulted in less legume biomass because of shading by maize. Growing season N2O-N emission factors varied from 0.02 to 0.25 and 0.11 to 0.20 % of the estimated total N input in 2015 and 2016, respectively. Growing season CH4 uptake ranged from 1.0 to 1.5 kg CH4-C ha−1 with no significant differences between treatments or years, but setting off the N2O-associated global warming potential by up to 69 %. Our results suggest that high yielding leguminous intercrops entail some risk for increased N2O emissions when used together with recommended fertilization rates, but can replace part of the fertilizer N without compromising maize yields in the following year and thus support CSA goals while intensifying crop production in the region.

scholarly journals Nitrogen Immobilisation and Microbial Biomass Build-Up Induced by Miscanthus x giganteus L. Based Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Triticum Aestivum L ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Miscanthus X Giganteus ◽  
Organic Fertilisers ◽  
Biomass N ◽  
Set Up

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.

Evidence of itinerant breeding of the Red-billed Quelea Quelea quelea in the Ethiopian Rift Valley

Ibis ◽  
2008 ◽  
Vol 128 (4) ◽  
pp. 469-482 ◽  
Author(s):  
M. M. JAEGER ◽  
R. L. BRUGGERS ◽  
B. E. JOHNS ◽  
W. A. ERICKSON
Keyword(s):  
Rift Valley ◽  
Ethiopian Rift
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