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

Urea fertilizer → Yield

A clear tendency, not consistent

64 %

of 22 studies with a clear result report a significant increase

+23 %

typical change (13 studies with numbers)

studies · 30 findings

Count each study by

24 studies · 30 findings

What the studies show

14 of 22 studies report a significant increase (64 %, 95 % confidence interval 43–80 %).

By the direction of each study’s results, significant or not: 17 of 23 studies with a direction point up (74 %, 95 % confidence interval 54–87 %; sign test p = 0.035).

↑ 14 increase
↓ 4 decrease
= 4 no effect
? 2 unclear

How large: typically +23 % (middle half +7 % to +48 %), from 13 studies with numbers
Basis: 24 studies, 30 findings; 0 entered by hand, 24 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 64 % of the studies under urea fertilizer, stays the same in 18 % and goes down in 18 %.

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…