Agriculture Reference
In-Depth Information
was measured with a portable pH meter (pHScan 3), and the electrical
conductivity, the total dissolved solids and the temperature were measured
with a Sension conductivity-meter.
Laboratory analyses
The samples of irrigation water were tested for chemical and biological
components, including major elements (N, P, K) from fertilizer, minor and
trace elements and heavy metals. Chemical parameters were determined by
classic chemical analysis methods. The total alkalis and the chemical oxygen
demand were determined volumetrically; other parameters were determined
colorimetrically (Berl, 1951; Hach Chemical Company, 1979; Alexeev, 1980).
Lead (Pb) and cadmium (Cd) were analysed after extraction with a
chloroformic solution of dithizone. Colorimetric analyses were conducted
with a Hach spectrophotometer, either a model 2000 or a model 1105.
The irrigation water samples were also tested for total coliform, fecal
coliform, fecal streptococci, Escherichia coli and helminths eggs. Presumptions
and count tests were undertaken using the most probable number (MPN)
method, determined by culturing a certain number of samples (generally five)
and (or) diluting these samples. The estimation is based on the principle of
dilution until extinction (Ayres and Mara, 1997; Tanawa and Djeuda, 1998;
Kiyombo, 2005). Escherichia coli was identified with Kovac's reagent
(Kiyombo, 2005), and helminth eggs were identified with the use of a
binocular microscope (Olympus CH20) after centrifuging (Kubota centrifuge).
Evaluation of Projet de Composti`re de Quartier compost
Compost is produced by the aerobic breakdown of vegetable wastes and
provides a strong fertilizer input for crops. The need for fertilizer in the
Centre Agricole de N'djili precipitated the application of compost. As part of
this study, an experimental garden was planted to evaluate the effect of
compost on the productivity of Amaranthus hybridus, one of the most prolific
crops in Kinshasa (Mokili, 1998; Boole, 2000).
Six vegetable beds were fertilized with compost or with sludge (SLU) and
watered with wastewater (WW) or with faucet water (FW). The vegetables
were measured from the base to the last bud with a tape measure. The basal
diameter was measured with vernier callipers. A tape measure was also used
to measure the length of leaves from the stem to the tip. Vegetables were
divided into three sample zones, each with an area of 1m
2
, and then weighed.
R
ESEARCH
F
INDINGS
Typology and location of urban agriculture in Kinshasa
In Kinshasa, urban farmers can be found in mountain basins, residential plots,
along main roads and in the hills, as well as in peri-urban areas.
