Spatial variability of selected soil properties at the University of Cape Coast teaching and research farm

Abstract

Knowledge of soil spatial variability and the relationships among soil properties are important for the evaluation of agricultural land management practices and soil research. The study was conducted to assess the spatial variability of selected soil properties on a 2.17 ha field at the School of Agriculture Teaching and Research farm from March to October, 2010. A stratified random sampling design was employed in the study. Samples were collected from two depths 0-10 cm and 10-20 cm at each sampling point. A total of 1,510 samples was obtained over the 2.17 ha research site. Twenty-one soil physical and chemical properties were determined on the samples. Classical and geostatistical analyses were performed on the data, using the GENSTAT statistical package. The study revealed general deficiencies in the amounts of soil macro and micronutrients. These were attributed to random and systematic variation in consolidation, mineralization, compaction, leaching and eluviation-illuviation of silicate clays and erosion. Non-spatial dependence of soil properties was ascribed to random variation whilst spatial dependence in other properties was attributed to systematic variations. Spatial dependence in soil properties varied within 25 m. Sampling intervals of less than 6 m and 11 m were suggested for top and subsoils respectively in order to reveal extra spatial patterns of soil properties.