From where do plants get their nitrogen compounds?

Question

When animals eat plants, they get nitrogen compounds that their bodies need. Plants do not make these nitrogen compounds. So from where do plants get their nitrogen compounds?

Answer 1

The soil and the rain mostly, some by converting sunlight

Answer 2

Yes, nitrogen fixation puts nitrogen into usable form for plants.  Not all plants, like legumes, are associiated with nitrogen fixing bacteria.

Most plants get their nitrogen directly from the soil as either nitrate or ammonia (in the form of ammonium+).  For confirmation, look on a bag of plant fertilizer.  Or look at how much the typical, midwest, American farmer spends on nitrogen fertilizers each year for his/her corn crop.

Answer 3

Nitrogen fixing bacteria that live around the roots of plants capture atmospheric N2 and convert it to organic forms that the plants can absorb and utilize.

From http://en.wikipedia.org/wiki/Nitrogen_fi...

"Nitrogen fixation is the process by which nitrogen is taken from its natural, relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds such ammonia, nitrate and nitrogen dioxide.

"Nitrogen fixation is performed naturally by a number of different prokaryotes, including bacteria, actinobacteria, and certain types of anaerobic bacteria. Microorganisms that fix nitrogen are called diazotrophs. Some higher plants, and some animals (termites), have formed associations with diazotrophs."