Management → Properties › Chemistry

Cover crops → Exchangeable/available potassium

A clear tendency, not consistent

83 %

of 6 studies with a clear result report a significant increase

+14 %

typical change (6 studies with numbers)

studies · 7 findings

Count each study by

6 studies · 7 findings

What the studies show

5 of 6 studies report a significant increase (83 %, 95 % confidence interval 44–97 %).

By the direction of each study’s results, significant or not: 6 of 6 studies with a direction point up (100 %, 95 % confidence interval 61–100 %; sign test p = 0.031).

↑ 5 increase
↓ 0 decrease
= 1 no effect

How large: typically +14 % (middle half +11 % to +20 %), from 6 studies with numbers
Basis: 6 studies, 7 findings; 0 entered by hand, 6 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…