Management › Fertilization › Type of fertilizer → Properties › Biology

Manure → Yield

A clear tendency, not consistent

56 %

of 36 studies with a clear result report a significant increase

+17 %

typical change (27 studies with numbers)

studies · 63 findings

Count each study by

41 studies · 63 findings

What the studies show

20 of 36 studies report a significant increase (56 %, 95 % confidence interval 40–70 %).

By the direction of each study’s results, significant or not: 24 of 33 studies with a direction point up (73 %, 95 % confidence interval 56–85 %; sign test p = 0.014).

↑ 20 increase
↓ 7 decrease
⇅ 2 both
= 7 no effect
? 5 unclear

How large: typically +17 % (middle half -2 % to +57 %), from 27 studies with numbers
Basis: 41 studies, 63 findings; 0 entered by hand, 41 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, yield goes up in 56 % of the studies under manure, stays the same in 19 % and goes down in 19 %.

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…