Abstract
The effect of seedbed method on aggregate stability of soils and physiological maturity of yams under organic based manure was carried out on
2025 at the Teaching and Research Farm of Akwa Ibom State University, Nigeria to identify soil management. The experiment was a 3 x 3 x 2
factorial experiment, involving seed bed methods (ridge, mount and flat) as the main treatment, organic manure (poultry manure, piggery droppings
and cow dung manure) as the sub treatment and yam varieties (Discorea rotundata and Discorea alata) were the sub-sub treatments. Soil samples
were taken randomly from the experimental field at 0-20 cm depth, bulked for physico-chemical analysis of the soil. Five plants were randomly
selected from the inner rows of each plot and tagged for easy Identification for data collection. Data were collected on growth and yield parameters.
Data obtained from the soil properties, growth and yield parameters were subjected to statistical analysis. The results obtained revealed that the
soil was dominated by sand fraction (82.15 %), with low silt (9.50 %) and clay (8.35 %) contents, classifying it as a sandy loam. Control had the
highest aggregate stability indices of MWDD (11.67a), MWDW (16.18a), GMDD (0.17a), GMDW (0.94a), DR (0.54a) and PSDI (75.03a). Aggregate
stability decreased with increase in seedbed methods. Soil pH (in water) was 5.7. Organic carbon (0.85%) and total nitrogen (0.07%) were low.
Available phosphorus (9.40 mg kg⁻¹) was moderate. Exchangeable calcium (2.81 cmol kg⁻¹), magnesium (1.22 cmol kg⁻¹), and potassium (0.19 cmol
kg⁻¹) were moderate. Bulk density (1.48 Mgm-1) was slightly high, indicated minor compaction, while porosity (43.5 %) was moderate. The results
of Variety × seedbed interaction for number of leaves revealed that D. alata on ridge developed leaves that supported a larger photosynthate pool
for tuber bulking. D. rotundata had substantially fewer leaves under control and flat treatments, and had lower yields. Ridge × D. alata yields the
best canopy and tuber bulking. The results shows that seedbed methods had a strong influence on vegetative growth and yield (p < 0.001). Ridge
and mound seedbed methods improved yam tuber bulking than flat or control treatments, also produced larger canopies and more leaves, while
flat and control produced smaller canopies. Application of animal manures increase organic carbon and nutrient supply. Minimize post plant
tillage prevent aggregate break down.
Keywords: Seedbed methods, aggregate stability, organic based manure, yam physiological maturity.
jaerem NEW Essien, O. A 1A
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