Page 227 - Nutrient Management Planning Guide

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Chapter 6.1

Scenario 2: N-based; One Time, Two-Year Application Rate

When applying multiple years’ worth of N do not exceed AOPA NO

3

-N limits for the soil zone

(Chapter 4.4). In calculating available manure N be sure to account for mineralization of organic N in the year following the application. Since approximately 12% of the organic N fraction will become available in the year following application, the crop available N estimate must be adjusted for additional N: Available Organic N (years 1 and 2) = Total Organic N × (0.25 + 0.12) Crop Available N = Available Organic N (years 1 and 2) + Retained NH

4

-N

Liquid manure

Available Organic N, years 1 and 2 (g/L) = 1.9 g/L × (0.25 + 0.12) = 0.7 g/kg Crop Available N (g/L) = 0.7 g/L + 1.9 g/L = 2.6 g/L

The target application rate to supply 2 years worth of N would be:

Application rate (metric units) = 2 × 78 kg/ha ÷ 2.6 kg/1000 L * × 1000

= 60,000 L/ha

Application rate (imperial units) = 60,000 L/ha × 0.089 (Table 4.3.3)

= 5,340 gal/ac

*Nutrient concentrations in g/L are equivalent to kg/1000 L

Solid manure

Available Organic N, years 1 and 2 (g/kg) = 6.3 kg/t × (0.25 + 0.12) Available Organic N, years 1 and 2 (g/kg) = 2.3 kg/t

Crop Available N (g/kg) = 2.3 g/kg + 1.7 g/kg Crop Available N (g/kg) = 4.0 kg/t

The target application rate to supply 2 years worth of N would be:

Application rate (metric units) = 2 × 78 kg/ha ÷ 4.0 kg/t = 39 t/ha

Application rate (imperial units) = 39 t/ha × 0.4461 (Table 4.3.3)

= 17.4 tn/ac