Effects of Nitrogen Fertilizer Rate and Cutting Height on Morphological Characteristics and Yield of Elephant Grass (Pennisetum purpureum L.)

Abstract

Background: Elephant Grass (Pennisetum purpureum L.) is a forage grass with high potential to improve livestock production. However, the dry matter yield of the forage crop is low because of poor agronomic and soil fertility management practices.
Objectives: This study was, therefore, conducted to evaluate the effects of nitrogen fertilizer rate and cutting height on morphological characteristics and yield of elephant grass (P. purpureum L.).
Materials and Methods: Treatments were arranged in a 3 x 4 factorial arrangement in a randomized complete block design with three replications (3 cutting heights i.e., 7.5, 15, and 22.5 cm; and 4 nitrogen fertilizer rate i.e., 0, 69, 115, and 161 kg N ha-1). Data on morphological characteristics and yield of elephant grass (P. purpureum L.) were collected and subjected to the analysis of variance using the general linear model procedure of the statistical analysis system version 2004.
Results: Most morphological characteristics of elephant grass increased (P < 0.05) as cutting height and nitrogen fertilizer rate increased, except for weight per tiller, tiller diameter, and internode length. Forage dry matter yield was in the order of 0 < 69 < 115 = 161 kg N ha-1 and 7.5 < 15 = 22.5 cm. Looking at the combination of the two factors 115 kg N ha-1 x 22.5 cm and 161 kg N ha-1 x 15 cm treatments resulted in greater dry matter yield of 6.25 and 6.45 ton DM ha-1 cut-1, respectively, and 115 kg N ha-1 was economically feasible.
Conclusions: This study suggests that the rate of 115 kg N ha-1 x 22.5 cm cutting height is optimum for intensive cultivation of the forage crop with high dry matter yield at reduced nitrogen fertilizer cost.