Northeast Region Certified Crop Adviser (NRCCA) Study Resources

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In This Section

• Introduction
• PO 44 Setting a realistic goal
• PO 45 Determining crop nutrient needs
• PO 46 Environmental effects of nutrient loss
• PO 47 NRCS 590 nutrient management standard
• PO 48 Mass nutrient balance
• PO 49 P-based vs. N-based manure application
• PO 50 Surface application and immediate incorporation of manure
• PO 51 Precision feeding
• PO 52 Environmentally sensitive areas
• PO 53 Nutrient management plans
• PO 54 Calculate total manure production
• PO 55 Capacity factors in manure storage
• PO 56 Three option for P management
• PO 57 The P index
• PO 58 Impacts of practice on P index
• PO 59 Calculate crop P removal
• PO 60 Nitrate leaching index (LI)
• PO 61 Practices to reduce nitrate leaching
• PO 62 Manure odor issues
• PO 63 Agricultural air quality
• PO 64 Reducing pathogen concerns from manure
• Summary

Competency Area 6: Nutrient Management and Planning

PO 56. List the three options for P management as defined by USDA-NRCS (national level).

1. Agronomic soil test
2. Environmental P threshold soil test level
3. P index

If an agronomic soil test is done, manure or biosolids can be added in amounts where expected plant P uptake and removal is equal to the P that will be added.

Soil test P levels in surface soil can be used to determine whether or not the recommendation should be P-based.  If soil P test levels are below the critical level, then manure and biosolids applications can be N-based.  If soil test levels exceed the critical value, then recommendations are P-based.  A second higher critical value precludes manure or biosolids application.

A P index can be developed for fields, which integrates factors relating to potential P loss to evaluate the relative risk of P application to a field.  These include the P that might be transported from manure or biosolids and soil, the potential to transport that P to a body of water, how much rainfall might occur, and whether or not best management practices are in place.  The amount of manure or biosolids that can be applied is a function of the P index value.  If it is low enough, manure or biosolid application rates can be N-based.