<![CDATA[Soil organic matter (SOM) is a key agent of soil aggregation. Ample manuring combined with ground cover may cushion its rapid mineralization and hence typically low status in well-drained humid tropical soils. This study, conducted at two sites of sandy-loam and loamy-sand Ultisols in Nsukka, southeastern Nigeria, assessed the effects of prior ample manuring on aggregate stability, porosity/permeability, time to attain field capacity (timeFC) after saturation, and moisture content at field capacity (MCFC). Poultry-droppings manure was incorporated into the topsoil at 0, 25, 50, and 75 t/ha to effect contrasting SOM status. The plots were prepared in the 2019/2020 dry season, heavily mulch-protected and saturated weekly. TimeFC and the corresponding MCFC were monitored at ½ month after treatment (MAT), and together with other soil properties, at 1 and 2 MAT. At both sites, but mostly in the loamy sand with lower antecedent SOM, soil aggregation increased with SOM status. Soil bulk density generally decreased while total porosity increased with SOM status. These effects were more pronounced at 2 MAT. Soil permeability, soil pH, and P-availability always increased with SOM status. TimeFC consistently indicated similar values (8.11-9.11 h), being longer with higher than lower statuses (boundary, 21 g-SOM/kg), while MCFC increased steadily with SOM. Generally, SOM status influenced soil aggregation, compaction and MCFC, but not timeFC. Short-term manuring-associated increases in SOM above 21 g/kg could imply raising its status to improve structure-related – including hydraulic – properties of drought-prone tropical soils which, however, might not reflect in their speed of internal drainage.]]>
