Management › Tillage → Properties › Biology › Diversity

Conventional tillage → Species richness

A clear tendency, not consistent

55 %

of 22 studies with a clear result report a significant decrease

-15 %

typical change (10 studies with numbers)

studies · 45 findings

Count each study by

26 studies · 45 findings

What the studies show

12 of 22 studies report a significant decrease (55 %, 95 % confidence interval 35–73 %).

By the direction of each study’s results, significant or not: 2 of 20 studies with a direction point up (10 %, 95 % confidence interval 3–30 %; sign test p < 0.001).

↑ 2 increase
↓ 12 decrease
⇅ 2 both
= 6 no effect
? 4 unclear

How large: typically -15 % (middle half -28 % to -11 %), from 10 studies with numbers
Basis: 26 studies, 45 findings; 2 entered by hand, 24 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 0 % of the studies under conventional tillage, stays the same in 33 % and goes down in 50 %.

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…