Long-term soil disturbance due to regular tillage destroys the soil structure, particularly by reducing the soil organic matter content. This, in turn, can lead to declining crop yields. This study assessed the influence of wheat (Triticum æstivum L.) straw incorporation and timing prior to seeding at 6 Mg ha−1 (S+), relative to no straw (S−), on maize (Zea mays L.) growth and yield parameters, as well as on soil characteristics. There were four intervals between straw incorporation and maize seeding, i.e. 60, 45, 30 and 15 days before sowing. Compared to the S− (control), soil dry bulk density increased (p ≤ 0.05) under all S+ treatments. A significantly greater proportion of undesirable small aggregates (<0.5 mm), and a lesser proportion of desirable medium sized (0.5-8.0mm) aggregates, occurred under S− treatment, as compared to
$S_{60}^ +$
treatment. A similar, but less pronounced, trend was observed under
$S_{45}^ +$
treatment. This trend was also evident for the
$S_{30}^ +$
and
$S_{15}^ +$
treatments. Generally, incorporation of straw 60 days prior to sowing led to achieving the best soil structure in terms of aggregation. Compared to S−, the soil organic matter showed a weakly significant (0.05 ≤ p ≤ 0.06) increase under straw amendment. Seedling emergence, plant height, cob length, the number of grain rows per plant, the number of grains per cob, as well as 1000 grain weight and yield were the highest under
$S_{60}^ +$
, and the lowest under S−. The present study suggests that more research is necessary over longer time periods between straw incorporation and seeding on different crops, and in different soil types, in order to study the effects on soil properties, and on the growth and yield of crops.
