Physio-chemical Alterations and Early Growth Response in Application of Cow Dung and NPK Fertilizer to Irvingia wombolu Seedlings

This study examined the changes in selected physical [Sand, Silt and Clay] and chemical [pH, N, P, K+, Ca2+, Mg2+, Na+, Org. C] compositions of different soil samples, and their possible effect(s) on the early growth and responsse of Irvingia wombolu seedling, following application of cow dung (CD) and NPK fertilizer. Top soil samples (TS) of between 0 – 15cm depth were collected and applied on Irvingia wombolu at varying combinations (NPK 0 – 4) and (CD 0 – 4) as follows; top soil only (control group I), top soil + NPK (Group II), top soil + cow dung (Group III) and top soil + NPK + cow dung (Group IV). The soils were then taken to the laboratory and assayed for physio-chemical changes in major components as; pH, N, P, K+, Ca2+, Mg2+, Na+, Org. C, sand, silt and clay. Prior to, and after actual experimentation, the N, P, K, Ca, Mg, Na, pH constituents of the cow dung were also analysed for every two weeks on a total of 20 weeks period, thereafter, plant heights, leaf area, leaf number and stem girth were obtained and recorded. Using a sensitive weighing balance, 20 WAP destructive sampling was performed to ascertain the root and shoots weights after oven-drying for three days at about 75°C. Obtained samples were then analysed for the nutrient content of stem, root, and leaf. After data collection, comparisons of differences between means was conducted using the Fishers protected least significant test and Duncan Multiple Range Test (DMRT) with p-value set at 0.05 level of confidence. Careful observation of results revealed that Irvingia wombolu seedlings than those seedlings grown in only top soil medium (TS) with single fertilizer use (Group II). However, NPK 3 CD 3, NPK 3 CD 2 and NPK 2 CD 3 best support the early growth phase of Irvingia wombolu seedlings as compared to others. It is recommended that periods beyond 20 weeks should require another dose of these fertilizer combinations. Further studies aimed at corroborating this research are also recommended.