Nitrogen availability determines the long-term impact of land-use change on soil carbon stocks in grasslands of southern Ghana

Abstract

Abstract. Enhancing the capacity of agricultural soils to resist soil degradation and to mitigate climate change requires long-term assessments of land-use systems. Such long-term evaluations, particularly regarding low-input livestock systems, are limited. This study evaluated the impact of long-term land-use practices, condensed tannins (CT) and soil nutrient status on carbon cycling in arable and permanent systems of a tropical Savannah. Soil samples were taken (0–30 cm depth) from arable crop fields, grazed-seeded grassland, cut-use permanent crops and native grassland. Soil organic carbon (SOC) stocks ranged from 19.9 to 36.8 Mg SOC ha−1 (mean ± sd = 32.9 ± 0.2 Mg ha−1). SOC stocks were lower for grazed-seeded grassland relative to cut-use grass, legume trees and shrubs. Within sown systems, nitrogen availability seemed to be the most critical factor that determines the fate of the SOC stocks, with soil nitrogen (N) concentration and the SOC being highly correlated (r = 0.90; p

Top Dressing of Fertilizers: A Way Forward for Boosting Productivity and Economic Viability of Grasslands

“…Applying fertilizers in large quantities increase the productivity of grasslands [4]. Low nitrogen availability has been identified as a major cause of degradation of tropical pastures [5] and the constant removal of forage without proper supply of nutrients extracted by plants emphasizes the problems of grazing land degradation [6]. The application of nitrogen and phosphorus has proved to be effective in maximizing the production of dry matter [7] and nutritional status [8] of grasses.…”