Gypsum Requirement

Name: Gypsum Requirement
Author: North Dakota State University

North Dakota State University

DOCUMENTED

Published in academic literature

For:Researchers & AcademicsIndustry Professionals

Free

Download on the App Store

App Summary

The Gypsum Requirement app is a calculator designed for land managers and agricultural producers to determine the correct amount of gypsum needed to remediate sodic soils. The app is based on a standard remediation equation that calculates the amount of calcium needed to displace excess sodium, which, as the associated research explains, degrades soil structure and reduces water infiltration. The authors identify this calculation as a critical step within a broader management protocol—including proper drainage and leaching—to improve soil structure and productivity.

App Screenshots

Detailed Description

Functionality & Mechanism The Gypsum Requirement application, developed based on research from North Dakota State University, calculates the optimal amount of gypsum needed for sodic soil remediation. The interface prompts for the input of key soil analysis parameters, including initial and final Sodium Adsorption Ratio (SAR) or Exchangeable Sodium Percentage (ESP), soil bulk density, treatment depth, and cation exchange capacity. It also accounts for gypsum purity and application efficiency. Leveraging a standard remediation equation, the tool generates a precise gypsum requirement in metric (Mg/ha) or imperial (tons/acre) units.

Evidence & Research Context

The app's methodology addresses sodicity, a condition where excess sodium degrades soil structure through chemical dispersion and swelling, impeding water infiltration and root growth.
Associated research from North Dakota State University outlines a remediation protocol that requires a soluble calcium amendment, typically gypsum, to displace sodium from soil exchange sites.
This research explicitly references the Gypsum Requirement app as a practical tool for calculating the necessary amendment quantity based on the established remediation equation.
The scientific context provided distinguishes the remediation of naturally occurring sodic soils from the distinct chemical challenges presented by brine spills from oil extraction.

Intended Use & Scope This calculator is designed for agricultural professionals, soil scientists, and land managers involved in the remediation of sodic soils. Its primary utility is to provide a precise, site-specific gypsum requirement based on analytical soil data. The tool does not conduct soil analysis; its calculations depend entirely on user-provided laboratory results. For a comprehensive remediation plan, including drainage and leaching strategies, consultation with an agronomist is recommended.

Studies & Publications

1 publication

Peer-reviewed research associated with this app.

Non-Evaluative Reference

Sodicity and Remediation of Sodic Soils in North Dakota

Franzen et al. (2024) · NDSU Extension

Referenced in academic literature; no direct evaluation of the app

This publication defines sodicity as the presence of excess sodium relative to calcium and magnesium in the soil, quantified by the Sodium Adsorption Ratio (SAR). It explains the chemical and physical mechanisms—specifically dispersion and swelling—by which high sodium levels degrade soil structure, causing surface sealing, reduced water infiltration, and restricted root growth. The authors identify the geological origins of sodium in North Dakota, primarily derived from Cretaceous shale bedrock and glacial till, and describe the widespread distribution of these soils across the state. The guide outlines a remediation protocol requiring three essential components: adequate internal drainage (often via tile systems), the application of a soluble calcium amendment (typically gypsum), and sufficient water to leach displaced sodium. It details critical management steps, including deep soil sampling to identify natric horizons, calculation of gypsum requirements using the specific "remediation equation" or the NDSU Gypsum Requirement app, and the necessity of mechanical mixing to ensure amendments reach the depth of root restriction. The document also briefly addresses the remediation of brine spills associated with oil extraction, distinguishing their specific chemical challenges from naturally occurring sodic soils.

In the Media

Sodic Soil Problems? Try the NDSU Gypsum Requirement Calculator

North Dakota State University developed the Gypsum Requirement Calculator to help farmers determine precise gypsum application rates for sodic soils, using inputs like soil depth, bulk density, CEC, and sodium adsorption ratio values. The calculator addresses the challenge that "the amount of gypsum required is often in tons per acre" and "is no task accomplished with a few hundred pounds of gypsum." The web-based tool specifically targets sodic soils where gypsum can effectively improve soil structure and water movement by providing soluble calcium.

AgviseRead article