ABOUT NITROGEN DIAGNOSIS.

THE SERVICE NITROGEN DIAGNOSIS.

Base: see below.

From here you get a form for crop  data fieldwise.
You can transfer it to your Excel program according to description in the form.
Fill in your data and send back as attachment.
Or, you can print it out and send as a letter.
Or, write your data by hand and send.

Include the information you have and  for different years. Naturally, the information will be incomplete, but we have to make the best of the situation.

You get an answer with the quantifications and comments which can be made.

Mail to bertilsson@greengard.se

BASE.

Two principles for nitrogen diagnosis:

1. Sampling or measurements on the field or the crop to get information about the present soil or crop status.

    Examples: Plant analysis, Sensor measurements of different kinds, Soil N measurements.

2. Aquiring information about the normal functioning of the field concerning nitrogen to use as a base for future planning.

The specific field system is characterized by : soil, climate, rotation, manure use, residue management, tillage system,  yield level, fertilizer use. etc

By systematic use of the information which is available concerning yields, protein contents, other crop analyses, use of manure and fertilizers, nitrogen input and output, it is possible to get a picture of the nitrogen situation . A perspective of some years is needed. 

Zero plots give additional information about nitrogen delivery from the soil. Yara  Zero Plot  gives an estimation of soil N delivery by means of straw measurements on "No N"  and "Normal N". Just keep a small area (at least 1 m width) free from fertilizer N. Measure the straw length before harvest.
 Simple, direct, no cost. Calibrated for barley and wheat.



MORE ABOUT NITROGEN DIAGNOSIS AND INDICATORS.

There is a connection between nitrogen status and protein content, and especially important is the nitrogen status at grain filling.

Example 1.
If the protein content is below 11 available N is low at grain filling. Irrespective of the fertilizer dose no residual N is left.

Example 2.
If the protein content is above 12 in spite of moderate fertilizer dose, the soil delivers N during grain filling. The N can come from the applied fertilizer or from soil mineralization. There is a risk for elevated residual N in the soil.

If the field regularly behaves as example 1, an increase in the fertilizer dose should be considered. If the dose is already high, consider nitrogen form, spreading and timing.  Concerning environment, the fertilizer has not increased N losses after the crop. However, leaching in Spring and Summer may have occurred.

If the field behaves as example 2, probably the fertilizer dose can be reduced. Both the economy and the environment should be gaining. There are, however, qualily factors to consider in some cases.

Other factors, as yield level, cropping and fertilization history etc, needs to be included in the considerations.

This base is presented in a report (Swedish):
Indikatorer för bedömning i efterhand av odlingens kvävestatus.