<p>First, don't take that graph too literally, it is just a cartoon version and isn't quantitatively correct.  </p>

<p>The USSR heavily subsidized fertilizer until 1988.  When they ended the subsidy, fertilizer prices increased to market prices and use of fertilizer decreased.  Fertilizer use decreased further after the USSR fell a couple years later. </p>

<p>Fertilizer use in France, Germany, UK and Japan <a href="http://www.earth-policy.org/data_highlights/2014/highlights43" rel="noreferrer">peaked in the 1980s</a> and contributed to the decline. </p>

<p><img src="https://i.sstatic.net/wfgiG.jpg" alt="enter image description here"></p>

CC BY-SA 3.0
2014-10-24T12:26:11.397Z
2014-10-24T12:26:11.397Z
DavePhD
<p>I'm in an AP Environmental Science course, and while reading part of the chapter in my textbook about the nitrogen cycle, I saw this picture.</p>

<p><img src="https://i.sstatic.net/aahcm.png" alt="nitrogen human input"></p>

<p>What I was wondering is what caused that dip in the nitrogen input in about 1995? I've researched online, but I haven't found anything.</p>

CC BY-SA 3.0
2014-09-19T17:30:50.130Z
I assume it is the fall of the USSR.
arkaia
CC BY-SA 3.0
2014-09-19T18:20:16.437Z
The original figure is based on work by Galloway et al., 2004 (http://www.jstor.org/stable/4151466) and Smil, 2004 (Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world food production. MIT press). I don't have the book now, but he talks about the time evolution of reactive Nitrogen. You could check there. Also useful is: http://www.whrc.org/resources/publications/pdf/UNEPetal.2007.pdf
arkaia
CC BY-SA 3.0
2014-09-23T09:04:24.380Z
What exactly is the graph showing? Atmospheric nitrogen fixed in other compounds?
mart
CC BY-SA 3.0
2014-10-05T03:34:45.447Z
@aretxabaleta care to post as an answer?
David LeBauer
CC BY-SA 3.0
2014-10-25T01:21:32.663Z
I'm still trying to get the Smil book back to check on things, but the answer by @DavePhD seems to be the main point.
arkaia
<statistics><human-influence><nitrogen>
Break in human nitrogen input in 1990s
Kyranstar
# Break in human nitrogen input in 1990s

(Asked by: username_0 on 2014-09-19)

I'm in an AP Environmental Science course, and while reading part of the chapter in my textbook about the nitrogen cycle, I saw this picture.

![nitrogen human input](https://i.sstatic.net/aahcm.png)

What I was wondering is what caused that dip in the nitrogen input in about 1995? I've researched online, but I haven't found anything.

**Tags:** statistics, human-influence, nitrogen

> **Comments:**
> **username_1**: I assume it is the fall of the USSR.  
> **username_1**: The original figure is based on work by Galloway et al., 2004 (http://www.jstor.org/stable/4151466) and Smil, 2004 (Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world food production. MIT press). I don't have the book now, but he talks about the time evolution of reactive Nitrogen. You could check there. Also useful is: http://www.whrc.org/resources/publications/pdf/UNEPetal.2007.pdf  
> **username_2**: What exactly is the graph showing? Atmospheric nitrogen fixed in other compounds?  
> **username_3**: @aretxabaleta care to post as an answer?  
> **username_1**: I'm still trying to get the Smil book back to check on things, but the answer by @username_4 seems to be the main point.  

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## 1 answers

### Answer by username_4 on 2014-10-24. Score: 5 | Accepted answer

First, don't take that graph too literally, it is just a cartoon version and isn't quantitatively correct.

The USSR heavily subsidized fertilizer until 1988. When they ended the subsidy, fertilizer prices increased to market prices and use of fertilizer decreased. Fertilizer use decreased further after the USSR fell a couple years later.

Fertilizer use in France, Germany, UK and Japan [peaked in the 1980s](http://www.earth-policy.org/data_highlights/2014/highlights43) and contributed to the decline.

![enter image description here](https://i.sstatic.net/wfgiG.jpg)


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