Management → Properties › Biology › Microorganisms/Microbes

Cover crops → Microbial biomass Carbon

A clear tendency, not consistent

67 %

of 9 studies with a clear result report a significant increase

+27 %

typical change (6 studies with numbers)

studies · 14 findings

Count each study by

11 studies · 14 findings

What the studies show

6 of 9 studies report a significant increase (67 %, 95 % confidence interval 35–88 %).

By the direction of each study’s results, significant or not: 8 of 8 studies with a direction point up (100 %, 95 % confidence interval 68–100 %; sign test p = 0.008).

↑ 6 increase
↓ 0 decrease
⇅ 1 both
= 2 no effect
? 2 unclear

How large: typically +27 % (middle half +12 % to +104 %), from 6 studies with numbers
Basis: 11 studies, 14 findings; 0 entered by hand, 11 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, microbial biomass Carbon goes up in 57 % of the studies under cover crops, stays the same in 29 % and goes down in 0 %.

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…