Phosphorus Management Tools

RESEARCH – PHOSPHORUS – NUTRIENT MANAGEMENT TOOLS
Researchers within the Land Grant University System or with CSREES funding are developing and evaluating new tools to help farmers, producers, and citizens to better manage nutrients, notably phosphorus (P), throughout agriculture. These tools include techniques that incorporate information technology, computer software to predict nutrient needs, sampling strategies, and programs aimed at decision support.

Precision Agriculture
Traditionally, we've managed our cropland based on the average soil condition and treated the entire field as a single unit. This method is sometimes inefficient, because you'll over-apply fertilizer in some areas and under-apply in others. Precision agriculture uses information technologies, like Global Positioning Systems (GPS), Geographical Information Systems (GIS), and remote sensing, to target nutrient inputs and management practices to site-specific variable field conditions. These technologies take into account unique soil/landscape characteristics resulting in less excess nutrients leaving the farm thereby reducing the pollution risk to ground and surface water.

In a project at Auburn University, yield monitors—devices that are mounted to harvesting equipment to measure crop yield and field position during harvesting— showed that acreage farmed with conservation tillage had significantly higher yields than the conventional system.

Research at Texas A&M University found that responses to variable-rate and blanket-rate P treatments were inconsistent. However, one of the most significant results from this study was that in two of three site-years, less P was applied with the variable-rate approach than with a recommended blanket-rate. Still, landscape position/slope at one site and soil type/soil calcium at another site had a greater impact than P treatment.

Researchers at the University of Wisconsin are developing a Precision Ag-Landscape Modeling System (PALMS) and using it to quantify P losses from fields.

A Kansas State University study is quantifying and demonstrating to producers and public interest groups the costs and benefits of implementing site-specific lime management to reduce P loading.

The potential for site-specific P fertilizer application in the Northeast is good, according to a study at Cornell University.

Researchers at the University of Kentucky concluded that both soil and landscape properties drove the crop’s yield response to starter P fertilizer, making no single factor important to predicting that response in any of the studied fields.

The Idaho OnePlan Nutrient Management Planner is the only officially recognized planning tool for creating certified nutrient management plans in Idaho. The State of Idaho and the USDA offer the software and training for individuals to become Certified Nutrient Management Planners in Idaho. This decision support tool was a collaborate effort developed by the University of Idaho, NRCS, U.S. EPA and the Idaho Associate of Soil Conservation Districts.

The Phosphorus Index
The Phosphorus Index is a simple field-based planning tool to assess the risk of phosphorus (P) movement from agriculture to water. Many versions of the P index exist and are in varying stages of evolution due to differing regional and geographic conditions. Much research through CSREES and the Land Grant System is being done to identify P sensitive watersheds, expand and improve on P indices, and to develop best management practices (BMPs) to reduce agricultural P losses to water.

A formalized group of scientists, SERA-17 (Southern Extension Research Activity with many members associated with Land-Grant Universities), was organized through the auspices of the Southern CSREES Region. This group discusses the research and management needs related to agricultural P and water quality.

Various State-Specific P Indices

Arkansas
Delaware
Maryland
New York
Pennsylvania
Vermont
Virginia
USDA-ARS has a Summary of Phosphorus Indices which lists what university or agency to contact for more information.

Regional Comparisons of P Indices

Development of Regionally-Consistent Phosphorus Source Coefficients for Use in Phosphorus Index Evaluations in the Mid-Atlantic Region
Phosphorus Indexes in Four Midwestern States: A Literature Review and Comparison
Customizing and Validating the P Index in Whole Farm Plans for Soils of the Northeast
P-Indices: A Southern Comparison

For more information on the current state of knowledge on the P Index, refer to the Phosphorus Index: Background and Status White Paper Summary produced by the National Center for Manure and Animal Waste Management funded through a USDA CSREES Fund for Rural America Grant.

Other Decision Tools
row crops Land Grant Universities conduct research and evaluation of nutrient management planning tools, software, and innovative technology that measures the effectiveness of planning and field P application techniques. With these tools, P is applied more appropriately to land, and P loss is reduced.

A joint research project between North Carolina State University, University of Hawaii, and Cornell University seeks to integrate and disseminate decision aid tools that facilitate the diagnosis of soil nutrient constraints and the selection of appropriate management practices for location-specific conditions.

The University of Vermont has tailored the CropMD computer software tool from Penn State University for Vermont conditions. With this tool and UVM Extension, ten farmers planned a total of about 8,000 acres.

As part of the Mid-Atlantic Regional Water Program, extension specialists and researchers at several Mid-Atlantic universities have developed phosphorus budgets for agricultural cropland.

Researchers at Cornell University, the University of Wisconsin and USDA-ARS developed a 6-part video seminar series to (1) present and review the science and methodology supporting the major nutrient management tools being used in New York, Wisconsin and elsewhere; (2) exchange information and share ideas for tool improvement, expansion, and to provide a basis for possible future collaboration between modelers in New York, Wisconsin and elsewhere; (3) identify the gaps in knowledge about nutrient management planning and identify future research and extension needs.

The University of Maine continues to utilize and evaluate the Whole Farm Nutrient Balance for P and N. This is an interactive Excel module that was developed in a regional research project that provides a quick gross overview of the nutrient balance for a farm which can be calculated in just a few minutes with a farmer.

The University of Missouri’s Spatial Nutrient Management Planner (SNMP) is a decision support tool, integrated with the Manure Management Planner developed at Purdue University, that facilitates the collection, analysis and presentation of spatial information related to nutrient management planning.