Abstract:
An experiment was conducted in 2014 and 2015 in the forest zone of Ghana to evaluate the effects of tillage,
maize-cowpea rotation, and residue management on runoff, soil erosion and maize grain yield. Four treatments
consisting of full tillage with continuous maize cropping and removal of crop residue (T1), full tillage with
maize-cowpea rotation with incorporation of plant residues (T2), minimum tillage with maize-cowpea rotation
and plant residues applied as mulch (T3), and minimum tillage with continuous maize cropping with residue
mulch (T4) were imposed on a randomized complete block design with three replications. Results showed a
very high runoff coefficient (15.53%) for T1, while runoff was significantly lower for T2 followed by T3 and
T4. This translated into very high total suspended sediments (5.7 t ha-1) and subsequently higher (p = 0.007)
total eroded soil (9.2 t ha-1). There seem to be a synergy between the presence of plant cover/mulch and residue
incorporation resulting in the lowest runoff for T2, as the combined effect probably improved infiltration and
soil permeability. In 2014, maize grain yield was lowest in the T1 (2.3 t ha-1) which was similar to T4 (2.4 t ha-
1). Grain yields for T3 (4.2 t ha-1) and T2 (4.1 t ha-1) were also similar but higher than the other two treatments.
In 2015, however, maize grain yields were significantly different among the various practices in the following
order: T1 (1.2 t ha-1) < T4 (2.2 t ha-1) < T3 (3.4 t ha-1) < T2 (4.0 t ha-1). The inclusion of a legume in T2 and T3
probably enhanced the soil fertility status resulting in higher grain yields. Hence, tillage practices including
cereal-legume rotation systems, coupled with effective management of crop residue is a promising strategy to
address soil and nutrient loss to water erosion and increase crop yield.
