Management › Tillage → Properties › Biology › Plants

Conventional tillage → Aboveground biomass

A clear tendency, not consistent

52 %

of 27 studies with a clear result report a significant decrease

-2 %

typical change (19 studies with numbers)

studies · 39 findings

Count each study by

28 studies · 39 findings

What the studies show

14 of 27 studies report a significant decrease (52 %, 95 % confidence interval 34–69 %).

By the direction of each study’s results, significant or not: 8 of 24 studies with a direction point up (33 %, 95 % confidence interval 18–53 %; sign test p = 0.152).

↑ 5 increase
↓ 14 decrease
⇅ 1 both
= 7 no effect
? 1 unclear

How large: typically -2 % (middle half -18 % to +6 %), from 19 studies with numbers
Basis: 28 studies, 39 findings; 1 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 layers of unstated depth, aboveground biomass goes up in 19 % of the studies under conventional tillage, stays the same in 26 % and goes down in 52 %.

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…