Management › Fertilization → Properties › Biology › Diversity

Inorganic fertilizer → Species richness

The studies disagree

45 %

of 22 studies with a clear result report a significant decrease

-7 %

typical change (11 studies with numbers)

studies · 30 findings

Count each study by

27 studies · 30 findings

What the studies show

10 of 22 studies report a significant decrease (45 %, 95 % confidence interval 27–65 %).

By the direction of each study’s results, significant or not: 9 of 22 studies with a direction point up (41 %, 95 % confidence interval 23–61 %; sign test p = 0.523).

↑ 5 increase
↓ 10 decrease
⇅ 1 both
= 6 no effect
? 5 unclear

How large: typically -7 % (middle half -19 % to +2 %), from 11 studies with numbers
Basis: 27 studies, 30 findings; 0 entered by hand, 27 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, species richness goes up in 13 % of the studies under inorganic fertilizer, stays the same in 50 % and goes down in 38 %.

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…