Environmental Engineering Reference
In-Depth Information
70
N = 4.4-6.5%
P = 2.1-3%
K = 0.9-1.7%
Ca = 0.6-0.7%
Mg = 1.3-1.4%
58.13
60
50
40
30
18.25
20
9.82
8.71
10
6.27
6.57
1.29
0.16
0
FIGure 14.3
Average kernel cake composition of solvent-extracted jatropha kernels on the basis of reported
data sets. (From Achten, W.M.J., et al.,
Biomass Bioenergy,
32, 1063-1084, 2008.)
taBle 14.5
summary of case studies using Jatropha seed cake as Fertilizer
dosage
(t/ha)
country
crop
comments
Mali
Pearl millet
5
46% yield increase in comparison to zero input
Zimbabwe
Cabbage
2.5-10
40%-113% yield increase in comparison to zero input.
Free from pest and disease, whereas cutworm infestation occurred with
cow manure application
Nepal
Rice
10
11% yield increase in comparison to zero input
India
Jatropha curcas
L.
0.75-3
13%-120% yield increase in comparison to zero input
Source:
Achten, W.M.J., et al.,
Biomass Bioenergy
, 32, 1063-1084, 2008.
phytotoxicity of overapplication of jatropha seed cake. One study showed phytotoxicity to tomatoes,
expressed in reduced germination, when seed cake was applied at high rates of up to 5 t /ha (Achten
et al. 2008).
The cake is also used as feedstock for biogas production through anaerobic digestion before
using it as a soil amendment. Staubman et al. (1997) obtained 0.446 m
3
of biogas, containing 70%
methane (CH
4
), per kilogram of dry seed press cake using pig manure as inoculum. Radhakrishna
(2007) reported a total production of 0.5 m
3
biogas/kg of solvent-extracted kernel cake and 0.6 m
3
biogas/kg of mechanically de-oiled cake using specifically developed microbial consortia as inocu-
lum. The fact that jatropha seed cake can be used for different purposes makes it an important
byproduct. Recycling of wastes as a fertilizer can help to reduce inputs needed for jatropha cultiva-
tion and other crop cultivation or it can produce extra energy in the form of biogas. From an envi-
ronmental point of view, anaerobic digestion of the cake in the biogas plant and application of the
effluent to the agricultural field is thought to be the best practice at present. A number of questions
