Management › Fertilization › Type of fertilizer › Inorganic fertilizer → Properties › Biology › Diversity

Urea fertilizer → Shannon index

A clear tendency, not consistent

40 %

of 5 studies with a clear result report a significant decrease

–

too few studies with numbers for a size

studies · 12 findings

Count each study by

7 studies · 12 findings

What the studies show

2 of 5 studies report a significant decrease (40 %, 95 % confidence interval 12–77 %).

By the direction of each study’s results, significant or not: 0 of 5 studies with a direction point up (0 %, 95 % confidence interval 0–43 %; sign test p = 0.063).

↑ 0 increase
↓ 2 decrease
⇅ 1 both
= 2 no effect
? 2 unclear

How large: only 1 studies with numbers, too few for an effect size
Basis: 7 studies, 12 findings; 0 entered by hand, 7 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…