Agriculture Reference
In-Depth Information
Table 2.1 Chemical characteristics of soil fertility amendments
Treatment
TKN
(%)
Org C
(%)
Org M
(%)
P
(%)
K
(%)
EC
(ms/cm)
pH
Compost
1.06
6.75
11.64
1.84
3.22
n.a.
7.3
Potting mixture
0.06
n.a.
0.75
n.a.
n.a.
0.31
7.0
Poultry manure
1.14
4.91
8.50
n.a.
n.a.
7.86
7.4
EC, electrical conductivity; TKN, total Kjeldahl nitrogen.
produced and evaluated in field trials was made from a 3 :1 ratio of market
waste and dewatered fecal sludge. Organic market wastes were obtained
from the main waste bins of the Kumasi Central Market. The sludge was
obtained from public toilet septic tanks and was dewatered on a drying bed
at the compost plant. Details of the dewatering facilities and compost
production are described in the IWMI report (2003). The compost, poultry
manure and test soils were analysed using established methods at the Soil
Research Institute (SRI) in Kumasi and are presented in Table 2.1.
Germination experiment
The eight common vegetables used in the germination experiment were
tomato (Lycopersicon esculentum), sweet pepper (Capsicum annuum), okra
(Hibiscus sabdariffa/esculentus), carrot (Daucus carota), garden eggplant
(Solanum melongena), lettuce (Lactuca sativa), cabbage (Brassica oleracea
capitata alba) and spring onion (Allium cepa). Thirty seeds of each vegetable
were planted into trays filled with one of five soil treatments. The soil
treatments were a mixture of potting soil and fresh compost at 0, 12.5, 25, 50
and 100 per cent. The seeds were loosely placed on the surface and lightly
covered with soil. Okra seeds, being the largest seeds used, were soaked in
water overnight (16 h) before planting. Seedling trays were placed in a
screenhouse for three weeks, where temperatures ranged between 25 and
308C, and watered daily to maintain sucient moisture.
Germination was counted every day for 15 days and was considered
successful when the seed radicle protruded from the surface of the soil. The
average time to emergence (ATE) was calculated as:
ATE
¼
½
P
ð
number of germinated seeds on ith day
ith day
Þ
ð
P
germinated seeds on last day
Þ
After three weeks seedlings were harvested by uprooting and washing the
root soil. The length of the primary taproot, shoot and fresh weights were
also measured.
Nematode suppression experiment
A factorial experiment was designed with two vegetables (lettuce and tomato
plants), six soil treatments and two nematode treatments (with and without
