Effects of Faidherbia albida on some important soil fertility indicators on agroforestry parklands in the semi-arid zone of Ghana

Abstract

A study was conducted in the Guinea and Sudan Savannah zones in the Upper East Region of Ghana to investigate the effects of Faidherbia albida on some important soil fertility indicators. Soil sampling and analysis, litter trap, and litter bag techniques were employed to determine the soil’s content of major nutrients, the rate of litterfall production and litter decomposition, respectively. Analysis of variance (ANOVA) was performed to determine differences among treatment means, while Tukey’s highest significant difference (HSD) was used to perform post hoc tests among means within the same sample set. Soils under F. albida tree canopies were found to contain significantly higher organic carbon and total nitrogen than those outside the canopies. Peak leaf litter production occurred during the first three months of the onset of the rainy season. Annual leaf litterfall was 340 g m-2 year-1 in the Guinea Savannah zone and 264 g m-2 year-1 in the Sudan Savannah zone. The high leaf litterfall, followed by high decomposition and mineralization at the beginning of the cropping season, the high nutrient content of its leaves, coupled with its nitrogen fixing ability, make F. albida a potential candidate for soil improvement and improved productivity of major crops in smallholder farming systems. About 37 and 59 adult F. albida trees will be required to supply significant amounts of nitrogen in the Guinea and Sudan Savannah zones, respectively.  Key words: Litter bag technique, litter decomposition, litter fall, litter trap technique, soil organic carbon, soil