Abstract:
Background and aims Degradation of physical, chemical and biological properties of soils in sub-Saharan
Africa mainly results from little or no organic resource
application coupled with sub-optimal fertilizer application. A study was conducted over three seasons, from
March 2010 to August 2011, to evaluate potential of six
organic materials (bagasse, cow manure, filtermud,
maize stover, sugarcane straw and Tithonia diversifolia)
for compost production and their influence on maize
yield and soil fauna diversity.
Methods Treatments comprised of the six composts,
commercial fertilizer and no-input control, laid out in
randomized complete block design in four replicates.
Soil macrofauna were collected using soil monolith
method. Data obtained were subjected to analysis of
variance (ANOVA) using GENSTAT whereas differences were evaluated using Fisher’s least significant difference (LSD). Correlation between macrofauna and
soil chemical properties was done using CANOCO 3.1.
Results The ANOVA showed significantly higher N
and P on filtermud (10.0 g N kg−1 and 979 mg P kg−1
)
and T. diversifolia (9.6 g N kg−1 and 614 mg P kg−1
)
composts. Generally, amending soils with composts
increased C, N and P of the soil by 90 %, 29 % and
20 %, respectively, while fertilizer treated plots recorded
42 %, 4 % and 110 % increase in C, N and P, respectively. Control plots recorded 25 % increase in C, but
15 % and 50 % decline in N and P, respectively. Maize
yields were highest in fertilizer (4.4 Mg ha−1
), followed
by composts (2.8 Mg ha−1
) and lowest in control plots
(1.4 Mg ha−1
). Soil macrofauna responded positively to
addition of composts. Isopterans, Oligochaeta and
Hymenopterans dominated the sites constituting 44 %,
26 % and 17 %, respectively of all the macrofauna.
Relationships between macrofauna and soil chemical
properties were positively significant.
Conclusions Results of this study demonstrate the potential of composts in improving soil biodiversity and
crop productivity.
