Management › Fertilization › Type of fertilizer → Properties › Physics

Nitrogen fertilizer → Bulk density

A clear tendency, not consistent

50 %

of 10 studies with a clear result report a significant decrease

-2 %

typical change (7 studies with numbers)

studies · 12 findings

Count each study by

11 studies · 12 findings

What the studies show

5 of 10 studies report a significant decrease (50 %, 95 % confidence interval 24–76 %).

By the direction of each study’s results, significant or not: 3 of 9 studies with a direction point up (33 %, 95 % confidence interval 12–65 %; sign test p = 0.508).

↑ 1 increase
↓ 5 decrease
= 4 no effect
? 1 unclear

How large: typically -2 % (middle half -5 % to +0 %), from 7 studies with numbers
Basis: 11 studies, 12 findings; 1 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 top 10 cm, bulk density goes up in 20 % of the studies under nitrogen fertilizer, stays the same in 20 % and goes down in 60 %.

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…