Effect of Varying Rates of Poultry Manure on the Morphological Characteristics of Elephant Grass (Pennisetum purpureum)

Abstract

Elephant grass is native to tropical Africa and the sub-Saharan region and has been introduced as a valuable and popular forage crop in many tropical and subtropical countries. Poultry manure is a valuable source of organic matter and nutrients that enhance soil fertility and promote the growth of crops. This study investigated the effects of varying rates of poultry manure on the morphological characteristics of elephant grass (Pennisetum purpureum) at the Department of Crop Science Teaching and Research Farm, University of Nigeria, Nsukka. The experiment employed a Completely Randomised Design (CRD) with five treatments: 0 (control), 5, 10, 15, and 20 tons of poultry manure per hectare, replicated five times. Morphological parameters, including stem height, stem girth, leaf length, and number of shoots, were measured weekly for eight weeks after planting. The data obtained were analysed using analysis of variance (ANOVA). Results demonstrated that poultry manure significantly (P<0.05) influenced elephant grass growth from weeks 2 to 8, while only stem height was significant in week 1. Although the application rates of 10 and 15 t/ha did not differ significantly (P>0.05), the 15 tons/ha application rate consistently produced the highest mean values across all morphological parameters, closely followed by the 10 tons/ha rate. Notably, the control treatment (0 tons/ha) exhibited the lowest growth responses, highlighting the critical role of organic amendments in soil fertility and plant development. The 20 tons/ha rate underperformed compared to moderate rates, suggesting potential nutrient toxicity or soil structure complications at higher application levels. The study concluded that moderate poultry manure application rates (10-15 tons/ha) optimise elephant grass establishment by providing an ideal balance of nutrients, improving soil moisture retention, and enhancing microbial activity. Ultimately, the research recommends a 10 tons/ha application rate for farmers, balancing cost-effectiveness, environmental considerations, and forage production efficiency.