Monday, 7 November 2005
10

Soil Variability in an Organic Soil of the Everglades Agricultural Area.

Samira Daroub, Ming Chen, Orlando Diaz, and Viviana Nadal. University of Florida, Everglades Res. & Educ. Center, Belle Glade, FL 33430-8003

Cropping practices are important factors affecting soil variability in the organic soils of the Everglades Agricultural Area. The objective of this study was to compare the impact of cropping practices on selected chemical and physical properties of sugarcane, vegetable and virgin (uncultivated and unfertilized) fields located at the Everglades Research and Education Center. Soil samples from the surface 15-cm of each field were taken using a triangular grid sampling plan. All samples were analyzed for bulk density, moisture, organic matter (OM) content, pH, total P, water extractable P (Pw), acid extractable P (Pa), Ca, Mg, K and Si. Correlation, ANOVA, factorial analyses and contour mapping were used to analyze the data. Soil pH increased significantly from 5.1 to 7.0 for the vegetable and sugarcane fields compared to the virgin field. Total P, Pw, Pa, and acid extractable Ca, Mg and Si were also significantly increased in the cropped fields. The lowest soil depth (0.4 m), however, was found in the virgin and vegetable fields. The shallow depth of the virgin field is probably due to the low water table maintained in that field and lack of irrigation. We hypothesize that the change in properties in the cropped fields are due to an array of factors mainly mixing of mineral material from bedrock and roads, OM oxidation, water management including irrigation and depth of water table, and fertilization practices. Contour maps showed that the virgin field had the lowest variability in the majority of the properties measured.

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