Comparative Influence of NPK and Cow Dung Applications on the Growth and Survival of Irvingia Gabonensis Seedlings at Different Soil Samples

Abstract

At varying levels, one of the key determinants of plant growth and/or seedling survival rates is the controlled availability of basic micro-elements as Nitrogen, Phosphorus, and Potassium (NPK), as well as composes (organic) manure. In this study, the effects of varying chemical elements [pH, N, P, K⁺, Ca²⁺, Mg²⁺, Na⁺, Org. C] on early growth and survival of different soil samples of Irvingia gabonensis seedling was investigated. To achieve this, topsoil samples (TS) of between 0 – 15cm depth were first obtained, while applying varying combinations of NPK fertilizer and cow dung, CD (0 – 4) on Irvingia gabonensis seedling as follows; topsoil only (control group 1), topsoil + NPK (Group 2), topsoil + cow dung (Group 3) and topsoil + NPK + cow dung (Group 4).  Following the period of application of test substances, soil samples were then obtained, analyzed, and compared for changes in chief components of pH, N, P, K⁺, Ca²⁺, Mg²⁺, Na^+, and Org. C, for sandy, silt, and clay soils respectively. The pH component of varying soil samples was also assessed and compared (every two weeks) across groups for 20 weeks duration, while also observing and recording the physical changes in plant heights, roots and shoots weights, leaf area, leaf number, and stem girth. At the end of sample collection, comparative differences in means for assayed variables were conducted with Fisher’s least significant test, while assessing confidence levels of p-value < 0.05 as statistically significant. From our results, it was observed that Irvingia gabonensis seedlings grown with cow-dung and NPK combination (Group 4) performed better in growth (height, diameter, and leaf area) than those seedlings were grown in only topsoil medium (TS) with single fertilizer use (Group 2). However, NPK 3 CD 3, NPK 3 CD 2, and NPK 2 CD 3 best support the early growth phase of Irvingia gabonensis seedlings as compared to others. A more sophisticated approach to this study that explains the possible mechanisms of changes in Irvingia gabonensis following NPK and cow dung application on various soil samples is recommended.