Management › Tillage → Properties › Chemistry › Nitrogen compounds › Total Nitrogen › Total dissolved Nitrogen

Conservation tillage → NO3-/Nitrate

The studies disagree

44 %

of 34 studies with a clear result report a significant increase

+9 %

typical change (17 studies with numbers)

studies · 47 findings

Count each study by

35 studies · 47 findings

What the studies show

15 of 34 studies report a significant increase (44 %, 95 % confidence interval 29–61 %).

By the direction of each study’s results, significant or not: 16 of 28 studies with a direction point up (57 %, 95 % confidence interval 39–73 %; sign test p = 0.572).

↑ 15 increase
↓ 12 decrease
⇅ 2 both
= 5 no effect
? 1 unclear

How large: typically +9 % (middle half -30 % to +79 %), from 17 studies with numbers
Basis: 35 studies, 47 findings; 7 entered by hand, 28 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, NO3-/Nitrate goes up in 58 % of the studies under conservation tillage, stays the same in 25 % and goes down in 8 %.

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…