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Towards the Development of Environmental Soil Phosphorus Critical Levels in Agricultural Soils of Puerto Rico

FAES Project Number: SWS-03865

Mylavarapu, R.S. (UF/IFAS); L. Olivieri, G. Martinez,
and D. Sotomayor (UPR)
Funding Agency: USDA- CBAG
Duration: Short
Both in PR and FL – P sorption studies to determine water quality impacts
Joseph Nguyen - Chemist

Goals and Objectives
Multiple studies have clearly established that there is a direct relationship between the level of P in soil and that in surface runoff water fraction with regards to environmental impact assessment. However, the adaptation and validation of agronomic soil tests for P for the establishment of environmentally based critical soil P levels presents a series of challenges. This study aims to identify and validate a method for environmental impact assessment for P for similar soil types in Puerto Rico and Florida.

1. Establish relationships among the extracting capacities of various agronomic soil test phosphorus methods, and the corresponding biologically available P fractions, considering the mineralogical and chemical characteristics of soils of different pedogenic origin and varying P status.
2. Quantify the P associated with runoff and sediment in two soils of contrasting mineralogy under different rainfall patterns and soil status, and establish relationships between their runoff P losses and their corresponding soil test values.
3. Utilize a GIS to display an environmental classification index of different regions of the land, based on their P status, and specific climatologic, topographic, and soil chemical data.