Abstract:
Field experiments were conducted in the 1998 and 2004 cropping seasons to assess the impacts
of different mulching materials on weed control, soil temperature, soil moisture depletion and
performance of tomato (Lycopersicon esculentum Mill.) in Ibadan, a rainforest-savanna transi
tion ecological zone of Nigeria. The crop growth and fruit yield were studied under plastic
(grey-on-black), woodchip (Teak) and grass (Pennisetum) mulches, with handweeded and un
weeded as controls in a randomized complete block design with three replicates. Also assessed
were weed dry matter and species spectrum, soil temperatures at 5-cm and 15-cm depths, and
soil moisture depletion. Compared to unweeded control that had the least total fruit yield (2.7
t/ha in 1998 and 4.2 t/ha in 2004), mulch types and handweeded treatments increased the fruit
yield by 152-237% in 1998 and 188-202% in 2004. Compared to mean pooled fruit yield from
all mulched plots, unweeded treatment reduced tomato fruit yield by about 65% and 66% in
1998 and 2004, respectively. The weed control efficiencies of the mulches ranged between 91%
and 100%. Dicotyledon weed species dominated the plots in the two years accounting for
81.8% in 1998 and 90% in 2004. The number of low-growing weed species enumerated on the
plots was 11 in 1998 and 18 in 2004. After four weeks of no rainfall in 1998, moisture loss was
least (1.68±0.10%) under plastic mulch and highest (13.96±0.08%) on the unweeded plot. The
differences between morning and afternoon soil temperatures at 5 cm depth were low under
grass mulch, woodchip mulch and unweeded control (5.0-5.9oC) but high under plastic mulch
and handweeded control (8.7-8.9oC). Mulches are effective in weed control and conservation of
soil moisture, and the plant-based mulches are most effective in reducing soil temperature.
These improvements of crop growing environment resulted in increased tomato growth and
fruit yield.
