University of Maryland Extension

Harford County Nutrient Management Updates for March

Filling Out Your AIR
This month’s biggest question is: “how do I use the nutrient management plan to determine the total pounds of available nutrients applied from manure?”

Consulting your nutrient management plan, look at the page labeled “Recommendations using Organic Nutrient Sources”. There will be a column labeled “Available N-P2O5-K2O #/A”. That column will give the pounds per acre of each nutrient delivered by that particular manure applied at that particular rate of application.

The only thing that needs to be done is to determine the number of acres that received that application for the same crop. Then multiply the total acres by each nutrient value to get total pounds N-P2O5-K2O applied. That’s all there is to it.

Looking Forward: PSNT Testing
What is it, and why should I do it? The PSNT or Pre-Sidedress Nitrogen Soil Test is used only on corn fields that have a nitrogen credit from a previous crop or a manure application to determine if there is enough soil nitrogen to finish the crop.

Qualifying fields must not have received more than 50 pounds per acre of commercial nitrogen fertilizer this season. Soil samples must be taken at a critical time when the corn is 6-12 inches high. If fertilizer application is more than 50 pounds of nitrogen or if the corn is over 12 inches, this test cannot be done.

Results will determine if there is a need for a sidedress of additional nitrogen and are normally available in 24 hours.

There are several advantages to using the PSNT.

  • Split applications of nitrogen to crops allow the crop to use the nitrogen more effectively.
  • If there is enough nitrogen in the soil, the additional nitrogen application is avoided, saving time and money.
  • Nitrogen is not stable. Using this tool gives the grower confidence in the application of additional nitrogen or confidence in relying on the nitrogen credits.

PSNT testing is available for free at the extension office.

International Year of Soils Update
As noted last month, 2015 is the International Year of Soils. The Soil Science Society of America (SSSA) has worked with Jim Toomey to create 12 two-minute videos on monthly themes. The themes so far are “Soils Sustain Life,” “Soils Support Urban Life,” and “Soils Support Agriculture.” They offer a number of learning aids for children. Interested? Read more here.

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