Management › Residue and mulch management → Properties › Physics

Residue retention (no removal) → Bulk density

A clear tendency, not consistent

56 %

of 16 studies with a clear result report a significant decrease

-5 %

typical change (5 studies with numbers)

studies · 19 findings

Count each study by

17 studies · 19 findings

What the studies show

9 of 16 studies report a significant decrease (56 %, 95 % confidence interval 33–77 %).

By the direction of each study’s results, significant or not: 2 of 12 studies with a direction point up (17 %, 95 % confidence interval 5–45 %; sign test p = 0.039).

↑ 0 increase
↓ 9 decrease
⇅ 1 both
= 6 no effect
? 1 unclear

How large: typically -5 % (middle half -6 % to +1 %), from 5 studies with numbers
Basis: 17 studies, 19 findings; 2 entered by hand, 15 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, bulk density goes up in 0 % of the studies under residue retention (no removal), stays the same in 40 % and goes down in 60 %.

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…