Management › Fertilization › Type of fertilizer › Inorganic fertilizer → Properties › Chemistry › Nitrogen compounds › Total Nitrogen › Total dissolved Nitrogen

Urea fertilizer → NO3-/Nitrate

A clear tendency, not consistent

60 %

of 10 studies with a clear result report a significant increase

+131 %

typical change (5 studies with numbers)

studies · 10 findings

Count each study by

10 studies · 10 findings

What the studies show

6 of 10 studies report a significant increase (60 %, 95 % confidence interval 31–83 %).

By the direction of each study’s results, significant or not: 6 of 7 studies with a direction point up (86 %, 95 % confidence interval 49–97 %; sign test p = 0.125).

↑ 6 increase
↓ 1 decrease
= 3 no effect

How large: typically +131 % (middle half +100 % to +158 %), from 5 studies with numbers
Basis: 10 studies, 10 findings; 0 entered by hand, 10 read by the library

Every study counts once, however many findings it reports: one with 40 sampling dates does not outvote ten others. A study with a significant increase and decrease (say at different depths) counts as "both". A first synthesis for orientation, not a substitute for a systematic review.

Where the studies are

goes up
stays the same
goes down
both ways

Through the soil profile

Each layer on its own: a study that reports the topsoil and the subsoil counts in both. Choose a layer to see what goes with it.

goes up
stays the same
goes down
both ways

In the profile from the surface to 20 cm or more, NO3-/Nitrate goes up in 67 % of the studies under urea fertilizer, stays the same in 17 % and goes down in 17 %.

What makes a difference

The conditions whose levels differ most clearly, each with the outcome that differs most between its levels of at least 10 study layers. Choose a layer in the profile to see them for that layer alone, or a level here to filter by it.

Testing every condition on every study layer…

Along the conditions

Testing every condition on every study layer…