Long term soil experiments are one of the array of scientific approaches used to increase the understanding of changes in soil properties and soil-environment interactions that help in soil management to meet the challenges of doubling food production from the soil. The Samaru Long-term trial, modelled after the classical Rothamsted trial in England, is the oldest Long Term soil trial in Africa. This study investigated the influence of long term application of Dung (D), Nitrogen (N), Phosphorus (P) and Potassium (K) on soil morphological and physical parameters: soil texture, wilting point, field capacity, saturation, available water, saturated hydraulic conductivity, bulk density and depth. From the laboratory results of particle size analysis, SPAW: field and pond hydrology (USDA-ARS and WSU-BSysE) version 6. 1. 52 was used in determining other soil physical properties. SAS was used in analysis of variance and differences in means were separated using the Turkey s Studentized range (HSD) test.
