Management › Fertilization › Type of fertilizer → Properties › Physics

Manure → Bulk density

The studies disagree

55 %

of 11 studies with a clear result report a significant decrease

-1 %

typical change (6 studies with numbers)

studies · 13 findings

Count each study by

12 studies · 13 findings

What the studies show

6 of 11 studies report a significant decrease (55 %, 95 % confidence interval 28–79 %).

By the direction of each study’s results, significant or not: 3 of 11 studies with a direction point up (27 %, 95 % confidence interval 10–57 %; sign test p = 0.227).

↑ 3 increase
↓ 6 decrease
= 2 no effect
? 1 unclear

How large: typically -1 % (middle half -8 % to +6 %), from 6 studies with numbers
Basis: 12 studies, 13 findings; 2 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

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…