University of Maryland Extension

Crop Code Clarification

Q. I’m confused by the new crop codes for wheat and barley in NuMan Pro 4.2.  Can you provide some clarification? 

A. Changes in the last several years have necessitated new crop codes for these crops. 

First, based on research by Dr. Bob Kratochvil, fall and spring nutrient recommendations have been separated. 

Second, State of Maryland nutrient management regulations now require a Fall Soil Nitrate Test (FSNT) to justify fall nitrogen application on wheat and barley grown for grain. 

Third, regulations allow manure usage on fall-seeded crops to supply phosphorus on fields where phosphorus is recommended based on soil test.  There is a 50 pound of plant-available nitrogen (PAN) limit in these situations.  

Crop

Crop Code

Appropriate use of crop code

 Comments

Wheat
Barley

25
26

Typical grain production situations

Fall N rec is based on FSNT results and included in Note 41

Wheat/Double Crop Soybeans
Barley/Double Crop Soybeans

15

16

Typical double crop situations

Fall N rec is based on FSNT results and included in Note 41

Wheat; Fall P-based
Barley; Fall P-based

326
327

1) Allows manure utilization up to 50 # PAN when

2) P is recommended based on soil test and

3) FSNT allows fall N

1) Only useful if FIV-P is less than 90; 

2) must choose "Phosphorus" on scenario page (top of page) at Rec Base

Wheat/Barley; Fall organic utilization, low FSNT

21

1) Wheat or barley for grain production and

2) FSNT allows fall N (30 # PAN) and

3) Client wishes to use manure to meet N rec

Only appropriate for fields where a fall manure application is planned

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