Effect of land use on potassium form of coastal plain sands of Nigeria

The study evaluated the effects of land use on the forms of potassium in the coastal plain sands (CPS) landscape of southeastern Nigeria. It was observed that both land use and topography did not influence the distribution of different forms of potassium. Mineral constituted approximately 97.4%, whereas non-exchangeable (1.9%) and readily available (0.7%) forms represented 2.6% of total potassium. The relationships established between reserve, exchangeable and soluble indicated the origin of readily available potassium. Mineral form of potassium associated directly with clay, electrical conductivity, organic matter, sodium and acidity, but indirectly with sand, pH and base saturation. Reserve and fixed potassium each associated with organic matter, whereas fixed form additionally associated with sand and clay. Clay increases the tendencies for the release of potassium, whereas sand acts on the contrary including leaching losses. The study confirmed that organic matter, particle size fractions, extent of weathering and soil development influence the dynamics of potassium within the landscape of CPS of southeastern Nigeria.