Page 169 - Nutrient Management Planning Guide

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Chapter 4.3

Table 4.3.4 Manure Ammonium Nitrogen Retention Factors Based on Expected Volatilization Losses Occurring Between Application and Incorporation

Application Strategy

Weather Conditions

Average Cool-wet Cool-dry Warm-wet Warm-dry

Surface applied, incorporated within 1 day 1 0.75 0.90 0.85 0.75 0.50 Surface applied, incorporated within 2 days 0.70 0.87 0.81 0.69 0.43 Surface applied, incorporated within 3 days 0.65 0.85 0.78 0.62 0.35 Surface applied, incorporated within 4 days 0.60 0.83 0.74 0.56 0.28 Surface applied, incorporated within 5 days 0.55 0.80 0.70 0.50 0.20 Not incorporated 0.34 0.60 0.50 0.25 0.00 Injected 1.00 1.00 1.00 1.00 1.00 Cover crop 2 0.65 0.75 0.25 0.40 0.50

1 Use these factors for broadcast liquid manure (without incorporation) on bare soils.

2 Use these factors for broadcast liquid manure (without incorporation) on land with residue, such as direct-seeded fields or forages.

Created by Matt Oryschak, 2006

Retention Factors for Broadcast Liquid Manure

The retention of NH

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-N in broadcast liquid manure is dependent on the ability of manure to infiltrate into the soil. Once in the soil, NH

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molecules adsorb to soil particles, reducing risk of loss. In situations where there is ground cover, some of the broadcast manure will coat crop residues and remain exposed to the air, increasing the potential for losses.

Using these correction factors, retained NH

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-N in manure is calculated as:

Retained NH

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-N = NH

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-N × Retention Factor (from Table 4.3.4)

The estimated crop-available N content of the manure is then calculated as:

Estimated Crop Available N = Available Organic N (year 1) + Retained NH

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-N