Management › Fertilization › Type of fertilizer → Properties › Biology › Plants

Manure → Aboveground biomass

The studies disagree

55 %

of 11 studies with a clear result report a significant increase

+37 %

typical change (7 studies with numbers)

studies · 19 findings

Count each study by

11 studies · 19 findings

What the studies show

6 of 11 studies report a significant increase (55 %, 95 % confidence interval 28–79 %).

By the direction of each study’s results, significant or not: 6 of 10 studies with a direction point up (60 %, 95 % confidence interval 31–83 %; sign test p = 0.754).

↑ 6 increase
↓ 3 decrease
⇅ 1 both
= 1 no effect

How large: typically +37 % (middle half +6 % to +87 %), from 7 studies with numbers
Basis: 11 studies, 19 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 layers of unstated depth, aboveground biomass goes up in 55 % of the studies under manure, stays the same in 9 % and goes down in 27 %.

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…