Management › Tillage › Tillage system → Properties › Biology › Diversity

Zero tillage → Shannon index

The studies disagree

36 %

of 14 studies with a clear result report a significant increase

-1 %

typical change (9 studies with numbers)

studies · 26 findings

Count each study by

16 studies · 26 findings

What the studies show

5 of 14 studies report a significant increase (36 %, 95 % confidence interval 16–61 %).

By the direction of each study’s results, significant or not: 7 of 13 studies with a direction point up (54 %, 95 % confidence interval 29–77 %; sign test p = 1).

↑ 5 increase
↓ 4 decrease
⇅ 2 both
= 3 no effect
? 2 unclear

How large: typically -1 % (middle half -10 % to +7 %), from 9 studies with numbers
Basis: 16 studies, 26 findings; 0 entered by hand, 16 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, shannon index goes up in 60 % of the studies under zero tillage, stays the same in 0 % and goes down in 40 %.

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…