Management › Tillage → Properties

Conservation tillage → pH

The studies disagree

50 %

of 86 studies with a clear result report a significant decrease

-2 %

typical change (58 studies with numbers)

studies · 132 findings

Count each study by

87 studies · 132 findings

What the studies show

43 of 86 studies report a significant decrease (50 %, 95 % confidence interval 40–60 %).

By the direction of each study’s results, significant or not: 24 of 74 studies with a direction point up (32 %, 95 % confidence interval 23–44 %; sign test p = 0.003).

↑ 23 increase
↓ 43 decrease
⇅ 7 both
= 13 no effect
? 1 unclear

How large: typically -2 % (middle half -6 % to +1 %), from 58 studies with numbers
Basis: 87 studies, 132 findings; 12 entered by hand, 75 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, pH goes up in 27 % of the studies under conservation tillage, stays the same in 11 % and goes down in 56 %.

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…