Soil carbon stock and nutrient characteristics ofSenna siameagrove in the semi-deciduous forest zone of Ghana

Vincent Logah,Derrick Asante,Emmanuel Aburam Ofosu,Erasmus Narteh Tetteh,Justice Mawunyefia,Ebenezer Yao Adegah

doi:10.1515/geo-2020-0167

Abstract

AbstractWe report soil carbon stock (SCS) and nutrient characteristics of a pure stand ofSenna siameagrove in comparison with adjacent cropland usingt-test. This study was conducted in 2018 at the Kwame Nkrumah University of Science and Technology, Kumasi. Soil sampling up to 50 cm depth was carried out from five subplots in each ecosystem. The SCS of the grove at 0–15 cm depth was over 100% greater (30.78 Mg/ha) than that of the cropland (15.16 Mg/ha). Soil pH and total N content of the grove were 5.75 ± 1.22 and 0.10 ± 0.03% in the topsoil (0–15 cm) and 5.52 ± 0.80, 0.06 ± 0.01% and 5.03 ± 1.22, 0.04 ± 0.01% in the 15–30 and 30–50 cm depths, respectively. Although these values were greater in the grove than the cropland, the available phosphorus content was 3–4 fold greater in the latter soil. The two ecosystems affected soil organic carbon and total nitrogen contents significantly (p< 0.05) only in the topsoil, but had a significant influence on soil available phosphorus in both the topsoil and the subsoil. Sand content of the grove seemed to explain greater variability in its SCS (R2= 0.81) than clay content. The greater SCS of theSennagrove demonstrates its role in soil carbon storage in tropical climate in the era of climate change.

Highlights

Improper land use and management practices have contributed immensely to extensive land degradation in sub-Saharan Africa and other regions of the world
It is inferable that converting the Senna grove to cropland will cause a decline in soil carbon stock (SCS) in the surface soil by over 100%
This study shows the importance of Senna siamea in soil carbon storage and in enhancing soil nutrient status in tropical climate

Summary

Introduction

Improper land use and management practices have contributed immensely to extensive land degradation in sub-Saharan Africa and other regions of the world. Soil carbon stock (SCS) data of such ecosystems to enhance climate change actions and policies are considerably lacking in sub-Saharan Africa Programs such as Clean Development Mechanism, commenced under the Kyoto protocol, and the reducing emissions from deforestation and forest degradation (REDD+) through the United Nations Framework Convention on Climate Change (UNFCCC) provide financial assistance to support carbon sequestration and reduce greenhouse gas emissions from land use change [7]. This notwithstanding, limited data on SCSs of land use systems are hindering the execution of these mechanisms in tropical countries [8]. Despite the general understanding of the impacts of land use change as hazards to agricultural productivity, very few studies quantified the extent, rate, and process of soil nutrient depletion under different land use and management systems in sub-Saharan Africa [6]

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Discussion

Conclusion