01/13/25 - 104 New Stories - REAL Environmental & Conservation Leadership In PA: http://tinyurl.com/2zp7v28x
| Share this: | ||||
|
|
|
|
|
|
Spotlight - Penn State: Nitrogen Test Assists Farmers In Managing Nitrogen
|
|
One of the challenges livestock farmers face is managing the nitrogen needs of their corn crop when applying manure. Farmers have the challenge of maintaining optimum crop yields while minimizing cost and reducing nitrogen loss to the environment. This is a challenge because the nitrogen cycle is very complex with nitrogen potentially being lost to volatilization, denitrification, and leaching. The complex processes are influenced by temperature, moisture, soil drainage, soil organic matter levels, and source of the nitrogen. Predicting how much of the nitrogen applied in manure will actually be available for the crop is the challenge for livestock producers.
Research has provided farmers with a management tool to help with this assessment. This is the Pre-sidedress soil nitrate test for corn. The advantage of this test is that the samples are taken when the corn is 12 inches tall or at least a week before the corn is to be side dressed. By taking the sample after the spring wet period typically has passed and very close to the time of side dressing the corn the test more accurately measures the nitrogen status close to time when corn has the greatest demand for nitrogen.
It is important if using this test to apply only a minimum of fertilizer N in the spring (starter fertilizer and/or N used as an herbicide carrier). The manure application should be determined based on the history of the field, a manure analysis, how the manure will be handled, and on crop requirements for N estimated from the expected yield and crop history. The soil samples are taken when the corn is 12 inches tall or at least a week before planned side dressing. The test cannot be used however if the field has injected fertilizer or manure because of the difficulty of getting an accurate sample.
The samples are mixed and dried in the sun or under a heat lamp. The dried samples are then sent to a reputable soil testing lab for analysis to determine the nitrate-N levels. The nitrogen requirement is then determined using the worksheet found in the publication Agronomy Facts 17.
If the soil nitrate levels are greater than or equal to 21 ppm then no nitrogen is required. If the soil nitrate levels are less than 21 ppm then the worksheet calculation is completed. This calculation considers manure applied since the last crop, the previous crop and manure history in the last three years when determining the rate of nitrogen needed to complete the crop.
These tests enable farmers to better management the nitrogen applications and only apply nitrogen if the crop needs it. This is a win win for the producer and the environment.
By avoiding excessive nitrogen application the farmer saves a significant cost. By applying only the amount of nitrogen that is needed by the crop the risk of losing surplus nitrogen to the environment is reduced as well.
Download a special fact sheet for more information.
(Written by: Leon Ressler, Lancaster County Extension Director, Penn State Cooperative Extension, and reprinted from the Watershed Winds Newsletter.)
|
|
|
7/18/2011 |
|
| Go To Preceding Article Go To Next Article |
