Machanga SOM trial Kenya
- Objective
- (i) To determine the relationship between organic resource quality/quantity and the quantity/quality of the SOM pool and distinct SOM fractions for a set of soils and climates relevant for the target benchmark areas (ii) To evaluate the impact of inherent soil properties (e.g. texture) and climate on the relationships between organic resource quality/quantity and the quantity/quality of the SOM pool and distinct SOM fractions (iii) To quantify the effect of fertilizer N and growing crops on the relationships between organic resource quality/quantity and the quantity/quality of the SOM pool and distinct SOM fractions;
- Description
- The experiment aims at unravelling relationships between the quality of organic resources and the quantity/quality of the SOM pool and distinct SOM fractions as affected by various modifiers of the decomposition process.
- Data Access Statement
- Available to collaborators only
- Data Access Notes
- Anyone interested in using the data from SOM trials in Kenya needs to contact Bernard Vanlauwe and then it will be discussed if a collaboration is possible and access for free can be provided versus no collaboration with the cost to the data access will be agreed.
- Data license
- No data license
- Data policy
- No
- Organizations
- IITAresearch organisationETH Zurichresearch organisationSNSFfunding agency
- People
- Bernard Vanlauweprincipal investigatorConsultative Group on International Agricultural Research, Nayrobi, kenyaMagdalena Necpalovadata managerETH ZurichDepartment of Environmental Systems SciencesMonicah Mucheru-Munaexperiment managerKenyatta University, Nairobi, KenyaWaswa Wycliffeexperiment managerInternational Centre for Tropical Agriculture(CIAT), Kisumu, KenyaJoahn Sixprincipal investigatorETH Zurich, SwitzerlandDaniel Mugendiprincipal investigatorEmbu University College, Embu, Kenya
Site: Machanga
- Type
- research station field
- Location
- MachangaMbeere DstrictKenya
- Geographic location
- -0.4574444, 37.6603946
- Elevation
- 1022 Metres
- Slope
- 3°
- Visits permitted?
- Yes
- Visiting arrangements
- By arrangement with Monicah Mucheru-Muna
- Management
- The organic residues are applied only at the start of the first season. Each plot receives 60 kg P/ha and 60 kg K/ha per growing season. Tillage by hand
- Soil type
- arenosol
- Soil description
- Ferric Arenosol. Well drained (in places imperfectly drained), deep, yellowish red to reddish brown, loose, sand to loamy sand. Parental material: Quartz rich Basement System Rocks; predominantly granitoid gneisses; Erosion: Nil, site well conserved; Effective soil depth: Deep to very deep (>150 cm).
- Soil properties
Variable Depth Value (range) Units Ref year Estimated? Baseline? soil pH 0 – 15 Centimetres 5.27 2002 soil total carbon 0 – 15 Centimetres 0.3 Percent 2002 total soil nitrogen 0 – 15 Centimetres 0.02 Percent 2002 plant available phosphorous 0 – 15 Centimetres 6.28 parts per million 2006 cation exchange capacity 0 – 15 Centimetres 2.35 kilogram per mole 2002 sand content 0 – 15 Centimetres 80 Percent 2002 silt content 0 – 15 Centimetres 7 Percent 2002 clay content 0 – 15 Centimetres 13 Percent 2002 soil density 0 – 15 Centimetres 1.51 gram per cubic centimetre 2004 - Climatic type
- tropical savanna climate
- Climate properties
Variable Time period Value (range) Units precipitation 2002 – 2007 780 (563 – 1251) millimeter
Design period: (2002—)
- Design Type
- split split plot
- Description
- Plots measure 6 x 6 m
- Number of blocks
- 3
- Number of plots
- 33
- Number of subplots
- 66
- Number of replicates
- 3
- Number of harvests per year
- 2
- Crop
Crop Years grown maize - Factors
- Factor name
- Factor levels
- crop residue management process Plot application: Whole plot
Tithonia diversifolia (1.2 t/ha)
Tithonia diversifolia (4 t/ha)
Calliandra calothyrsus (1.2 t/ha)
Calliandra calothyrsus (4 t/ha)
maize stover (1.2 t/ha)
maize stover (4 t/ha)
sawdust (1.2 t/ha)
sawdust (4 t/ha)
farmyard manure (1.2 t/ha)
farmyard manure (4 t/ha)
control exposure
- nitrogen fertilizer exposure Plot application: Whole plot
control exposure
nitrogen (120 kgN/ha)
- cropping system
cropped
bare fallow
- Measurements
Variable Material Units Frequency Scale Comment grain yield trait maize t/ha biannual all cropped plots core biomass maize t/ha biannual all cropped plots stover biomass maize t/ha biannual all cropped plots plant biomass maize t/ha biannual all cropped plots soil organic carbon Soil % irregular sample per site total soil nitrogen Soil % irregular sample per site total soil phosphorous Soil % irregular sample site soil pH Not specified cropped plots concentration of nitrate in soil Soil mg/kg Collected 3 times during 2018 rainy season cropped plots concentration of ammonium in soil Soil mg/kg Collected 3 times during 2018 rainy season cropped plots