PSNT
Pre-Sidedress Soil Nitrate Testing
Free PSNT at LCCD!!
LCCD is offering free PSNT!
*Participation in the program offers free soil sampling, testing and side-dress recommendations to agricultural operators.
*In previous years, LCCD collected PSNT soil samples on the farm. We will still do this upon request, but we encourage farmers to drop off their own samples at our office.
When deciding which fields to have tested keep a couple things in mind:
The PSNT test is only intended for fields that have a long-term manure application history (received manure at least 2 out of the last 5 years)
50 lbs N/acre or less should be applied as starter fertilizer
Soil sampling needs to occur when the corn is about 12 inches tall, or at least 1 week prior to expected sidedressing
For instructions on taking soil samples for PSNT, visit Penn State Extension’s info page
Interested?
To be added to the testing list or for more information contact:
What is PSNT?
The Pre-Sidedress Soil Nitrate Test (PSNT) for corn measures the soil nitrate concentration, which is used to provide a recommendation for sidedress Nitrogen.
The total nitrogen (N) required for a corn crop is given by organic and inorganic N (ammonium N and nitrate N) sources. Farming practices such as regular manure application, reduced tillage and cover crops can lead to an accumulation of organic N in the soil. Ammonium N and nitrate N can be released when organic N decomposes, supplying N to crops during the growing season. However, due to the environment and soil health predicting the contributions of organic N can be difficult.
Ammonium N can be lost to volatilization if not incorporated into that soil, incorporation methods include tillage, injection or a timely rainfall. The PSNT can provide a measurement of N supply from organic sources and recovery of manure ammonium N to assist in making N fertilization decisions.
The in-season PSNT allows farmers to make fertilizer application decisions and just meet crop N recommendations. Precise management of N can lower production costs while maximizing crop production, and minimizing environmental N losses.
The importance of Nitrogen
Understanding the Nitrogen cycle helps understand how useful the PSNT is. Most of N (about 98%) is unavailable to plants because it is tied up in soil organic matter. The forms of nitrogen available to plants are ammonium N and nitrate N, these forms become available to the plant by the decomposing of N in organic matter.
Nitrogen Behavior
Partial Nitrogen Cycle
The Test
The Pre-sidedress Soil Nitrate Test (PSNT) for corn is designed to measure nitrate concentration, which can aid to in determining N supply from both manure and other organic N sources in the soil and to estimate the supply of soil N that will become available to the crop throughout the growing season.
How it Works
A soil sample is collected during the growing season, when the corn is 12 inches tall, or at least a week before sidedressing is planned to happen.
Soil samples are dried down and tested for nitrate concentration.
The nitrate levels and other information is provided into a formula to produce a sidedress recommendation.