Aboveground Biomass Production and Nitrogen Content of Gliricidia Sepium under Different Pruning Regime- A Case Study at the Department of Agroforestry Farm (Kwame Nkrumah University of Science and Technology-KNUST)

Abstract

Gliricidia sepium is considered one of the commonly used multipurpose legume shade trees in Ghana. Different pruning regimes affect the nutrient content as the amount of biomass produced by many multipurpose trees. In this study, the aboveground biomass (both fresh and dry matter) production and nitrogen content in Gliricidia sepium under different pruning regimes (4, 8 and 12 weeks) was studied. The study was carried out in the demonstration farm of Department of Agroforestry in the Faculty of Renewable Natural Resources-KNUST. A total of nine (9) Gliricidia trees were selected. The pruning frequencies were assigned to the selected trees, after an initial pruning of 1.2m from the ground. The data collected include; new fresh weight, dry weight and nitrogen content at the various pruning time. Also, the amount of nitrogen (N) in the new biomass was estimated at each pruning time. The result shows that the aboveground biomass production increased from 4 weeks to 12 weeks regime. Overall nitrogen concentration increased from 2.61% to 3.58% upon reducing the pruning frequency from 4 to 12 weeks, and total nitrogen content was much higher in 12 weeks (36.01g) than in the other pruning frequencies, due to biomass production been larger. In conclusion, the study highlights the potential of Gliricidia biomass as a source of N and green manure for both agricultural and agroforestry purposes. Hence pruning regime of Gliricidia should be considered in managing it for nutrient and manure purposes.