Estimating Manure P App Rates

Estimating Manure P App Rates

Purpose

Manure phosphorus application rates should be estimated. These estimates should be based upon the most recently available information for manure nutrient concentration (manure sample) and the estimate of crop nutrient needs. Since this information is not typically available at the time of a permit application, estimating manure phosphorus application rates as part of a permit is, at best, an educated guess made without essential information. However, the underlying principals and assumptions that will be used to estimate manure phosphorus application rates can be defined in a permit application. In addition, an example of the use of these calculations is shared in Section 12 - Annual Plan.

The results of the Phosphorus Index will determine which fields will receive manure at a N-based rated vs.P-based rates. For fields receiving manure at an N-based rate, this procedure can be used to determine excess P applications and approximate rate of P buildup in a field. The Phosphorus Index should be completed for all fields receiving manure at least every five years. It is suggested that the most recent results of a Phosphorus Index assessment be included in an permit application.

This section describes the calculations and assumptions that will be used to annually estimate individual field manure phosphorus application rates.

View the example and NE Phosphorous Index Table

Reference Materials

Please download (Save) these forms and software files to your local computer.

Nebraska CNMP – Land Application Workbook - Form 19 - Annual Field Plan for Phosphorus. pdf version (1 page, 89KB); MS Word Form (1 page)

Agricultural Phosphorus Management and Water Quality Protection in the Midwest: A Heartland Regional Water Coordination Publication, No. RP187
Resource for nutrient management planners on the risk of phosphorus delivery to surface waters; assessment of this risk, and management options to reduce this risk; targeted to U.S. EPA Region 7 comprised of Iowa, Kansas, Missouri and Nebraska.

Software

The Nebraska P Index is a spreadsheet tool for assessment of the risk of P loss from agricultural land to surface waters and review of factors contributing to P loss.
Software: Nebraska P Index: .xls  spreadsheet (2005); Instructions: NE P Index Documentation

Manure Use Plan for Nebraska: .xls Spreadsheet; Instructions.
Estimates the nutrient value of manure and accurately credits those nutrients against the nutrient requirements of a crop. Maintains an 11-year record for 25 fields for manure and fertilizer application rate plans. This spreadsheet can be used for creating and maintaining an annual nutrient plan.

The Manure Management Planner and Plan Generator (MMP) is a program developed and located at Purdue University for making nutrient management plans for crop and animal feeding operations.

Manure Management Planner Software & Instructions

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