SPATIAL AND TEMPORAL VARIABILITY OF SOIL FERTILITY IN TERRACED PASTURES

Abstract

A study was conducted to quantify temporal and spatial variables relative to soil test variability and to propose practices for improving soil sampling in terraced pastures. We sampled along a strip crossing multiple microreliefs (by-strips) and along a microrelief crossing fertilizer treatments. Soil samples were analyzed for pH and plant available nitrogen (N), phosphorus (P), and potassium (K). Temporal variability was consistently greater than spatial variability across the soil fertility parameters tested. Variation among pastures was negligible; however, terrace channels had an impact on soil fertility variability. The two sampling methodologies complemented each other to provide a clear picture about the spatio-temporal dynamics of nutrients in terraced pastures. Some recommendations that could improve soil sampling precision in terraced pastures include allowing substantial precipitation to occur between grazing and sampling and to collect soil cores representing all microrelief areas except terrace channels to form a composite sample.

Keywords:

• soil spatial
• temporal variability in terraced pastures