Vimala D. Nair

0000-0002-1096-284X

An Indicator for Risk of Phosphorus Loss from Sandy Soils

Vimala D. Nair, Willie G. Harris, Debolina Chakraborty, andDebolina Chakraborty

Sandy soils common in Florida have a low capacity to retain phosphorus (P), increasing the risk of P loss to water resources. This publication presents a practical indicator that combines soil test P with soil P retention properties to better assess the environmental risk of P loss. The indicator helps identify sites where P movement below the root zone is more likely and supports improved fertilizer management decisions. Its use promotes nutrient stewardship while maintaining crop productivity and protecting water quality.

Understanding Soil Phosphorus Storage Capacity

Vimala D. Nair, Willie G. Harris, Debolina Chakraborty, Debolina Chakraborty, andMyrlène Chrysostome

[ABSTRACT]

The Long-Term Contribution of Phosphorus from Agricultural Lands to Lake Okeechobee

Vimala D. Nair, Myrlène Chrysostome, and Willie G. Harris

The purpose of this publication is to explain the role of soil in the long-term contribution of manure phosphorus (P) from agricultural lands to south Florida's Lake Okeechobee. It also addresses the applicability of a recently developed procedure to evaluate a soil's potential to negatively impact water quality through P release from the soil. Revision by Vimala D. Nair, Myrlène Chrysostome, and Willie G. Harris, and published by the UF/IFAS Department of Soil and Water Sciences; 6 pp.

Phosphorus Sources and Risk Potential: Organic and Inorganic Fertilizers

Vimala D. Nair and Willie G. Harris

A UF/IFAS numbered Fact Sheet for Academic and Policy Makers audience(s).

The Potential for Plants to Remove Phosphorus from the Spodic Horizon

Debolina Chakraborty, Vimala D. Nair, Willie G. Harris, and Roy D. Rhue

A UF/IFAS numbered Fact Sheet.

An Introduction to Biochars and Their Uses in Agriculture

Rao Mylavarapu, Vimala D. Nair, andKelly T. Morgan
Other Contacts: Paul White

Extraction of Soil Nutrients Using Mehlich-3 Reagent for Acid-Mineral Soils of Florida

Rao Mylavarapu, Tom Obreza, Kelly Morgan, George Hochmuth, Vimala Nair, and Alan Wright

Soil testing is a multistep process starting with the collection of a sample that adequately represents the area or field to be tested. Due to wide-ranging soil conditions across Florida and the United States, multiple soil test methods exist. During the 1970s, Florida along with several other southeastern US states adopted Mehlich-1 (M1) as the official extractant for acidic soils. The UF/IFAS Plant Nutrient Oversight Committee approved the change from M1 to M3 in 2010. Based on observations of the interpretations, the technical committee revised the M3 interpretation in March 2014. The new interpretations have been correlated with the M1 interpretations, as closely and realistically as possible, so the actual nutrient recommendations are not changed.

Parameters for Site-Specific Soil Phosphorus Loss Modeling from Soil Test Data

Biswanath Dari, Vimala D. Nair, andWillie G. Harris

his publication presents predictive equations for estimating the Langmuir (KL) and Freundlich (KF) phosphorus adsorption coefficients from routine soil-test measurements of phosphorus, iron, and aluminum used in Phosphorus Saturation Ratio (PSR) and Soil Phosphorus Storage Capacity (SPSC) calculations. The approach eliminates the need for time-consuming adsorption isotherm experiments and provides a rapid, cost-effective method for obtaining key soil phosphorus retention parameters. These estimates can be incorporated into nutrient transport models to improve site-specific assessment of phosphorus dynamics and phosphorus loss risk from manure- and fertilizer-impacted soils.

Iron Oxide Strip as an Innovative Diagnostic Tool for Soil Phosphorus Management

Lilit Vardanyan andVimala D. Nair

Phosphorus (P) is essential for plant growth and productivity. Excessive application of P fertilizers has contributed to environmental degradation through runoff and leaching into waterways. Traditionally, the Mehlich 1-P and Mehlich 3-P soil tests have been used widely to guide fertilizer recommendations in Florida and many other regions. However, these may provide inaccurate estimates of plant-available P, especially in soils with diverse mineralogy or strong P-sorption capacity. This can result in suboptimal fertilization practices. Unlike standard soil tests, which rely on chemical extractants that may mobilize both labile and non-labile forms of P, the iron oxide strip P (FeO-P) method targets the fraction most relevant to plant uptake, offering a more reliable indicator of P availability. FeO-P mimics the absorptive behavior of plant roots to determine actual crop nutrient demand, providing an improved diagnostic tool for both agronomic and environmental applications.