Assessement of elemental nutrients and of organic matter quality in cultivated lands of Rufisque-Lendeng:

16.07.13 Colloque sur la recherche actuelle à Dakar/ Senegal 1

Assessent of elemental nutrients and of
organic matter quality in cultivated lands of
Rufisque-Lendeng
Jessica Roberts
Master Thesis in Biogeosciences

General Context
Lendeng
When an accident leads to an idea

Lendeng
www.maps.google.ch, retrieved the
4.06.13
Rufisque
Lendeng

http://www.unep.org/groundwaterproject/Countries/Senegal/Report/DecReport_02.pdf, retrieved the 23.06.13

Study Field
Conditions
●
2m x 7m of surface
●
Lactuca sativa var. Eden
●
7 weeks to grow
●
Irrigated with drinking water
●
14-36m depth of groundwater
Test Salad field (J.R.)

Problematic
Periurban Agriculture
A green Lung or a land of new potential ?

Urbanisation
Street built in 2012
through Lendeng (J.R.)
District of Rufisque nearby
the field of Lendeng
(Haruka 2012.)

Irrigation

Food
security
Salad cultivation field of Lendeng (J.R.)

1. To observe the change in
pedological process
2. Changes in soil
solutions with depth and
with time
Objectives

Method
Sample-Taking
Different elements of soil

5 - 40cm

CERAMIC POROUS CUP
Constellation and Depth
50 10050 50 10050 50 50
20
40
70
Depth ( cm)
Distance ( cm)

Results
Soil profile
The frame of nutrient exchange

Granulometry

Mineralogy

Mineralogy
First Lithological
Rupture

Mineralogy
Second Lithological
Rupture

Mineralogy – Fine Fraction

First Lithological
Rupture

Second Lithological
Rupture

Third Lithological
Rupture

Nutrielements
● Sodium
● Potassium
● Phosphate
● Sulphur
Granulometery
Organic Carbon
Acid elements
originally from clay
or sand
Limestone
& Parameters
linked with the
presence of
limestone
Magnesium
Fresh Organic
Matter

Results
Soil Water and Solution
The medium of nutrient transfer

Parameters showing a significant spatio-
and time development
Time
● pH
● Fluore
– Bromure
– Sulphate
● Organic Carbon and
Matter
Spatial
● pH, Conductivity and
Quantity
● Soluble ions (except
phosphat, calcium,
ammonium, potassium)
● Organic Carbon and
Matter

Horse Manure
Salad planting
Urea
NPK
1st Harvest
Nb leave 3 - 5 8 9 12 22
Length (cm 6 - 7 8 10 12 18

Chlorid
Sulphate

Ca2+
or
Mg2+
M
Na+
or K+

M

13
=
Limit of a Sodic Soil
Brady and Weil, 2008

4 mS/cm
=
Limit of a Salin Soil
Brady and Weil, 2008
mS/cm

Water pH of Soil
> 8.5
Sodic Soil

Conclusion
Assessment of nutrient flux
What is the future of the soil ?
● Soil
→ A complex construction of two or more soil
layers
● Soil solution
→ Indicating an important variation with depth
→ Nearly no variation with time
→ Signs for sodification process
(High evaporation rate and Presence of Na in surface)

Thank you for your attention!

References
www.carte_du_monde.net, retrieved the 3.01.12
Félix, J. (2006). Caractérisaton des eaux d’arrosage, de leurs impacts sur l’environnement et techniques d’épuraton extensive par
lagunage (Dakar, Sénégal). Travail de diplôme sci. nat. environ. Univ Lausanne et Univ. Genève, 114p.
Gobat JM, Aragno M, Matthey W (2010). Le sol vivant : Base de pédologie – Biologie des sols. 3 Editon, Presses polytechniques et
universitaire romandes, 3.11, pp. 84-86 et pp. 371-395.
Hitz C. (2012). Synergie ou concurrence entre la vielle et son environnement : Renforcer les synergies entre la ville et l’agriculture à
Dakar. Université de Lausanne, Urbamonde Genève.
IAGU (Insttut de l’agriculture et geston urbaine) (2011). Le maraîchage urbain à Lendeng (Rufsque, Sénégal). Rapport et poster,
Insttut Africain de Geston Urbain), Juin 2011.
INRA (2006). Système de prélèvement de la soluton du sol par bougies poreuses, INRA Avignon, Unité des Sciences du Sol,
www.maps.google.ch, retrieved the 7.01.12
SPS (Sahel People Service) (2010). Centre d’AFAFA. www.sahelpeopleservice.com, consulté en octobre 2012
Brady, Nyle C, and Ray R Weil (2008). The Nature and Properties of Soils. Upper Saddle River, N.J.: Pearson Prentce Hall.

Salinisation and Sodification

Method
Ceramic Porous Cups
or how to capture the (soil) solution

Development of Condensation Index
in Soil Solution (SS) and Water Extracted Soil
Solution
Deeper Layers

Development of Condensation Index
in Soil Solution (SS) and Water Extracted Soil
Solution
Upper Layers

Method
Ceramic Porous Cups
or how to capture the (soil) solution

Assessement of elemental nutrients and of organic matter quality in cultivated lands of Rufisque-Lendeng:

Contenu connexe

Similaire à Assessement of elemental nutrients and of organic matter quality in cultivated lands of Rufisque-Lendeng:

Plus de Catherine Pfeifer

Assessement of elemental nutrients and of organic matter quality in cultivated lands of Rufisque-Lendeng: