The Source of the Supply of Nitrogen.

Te Aroha News, Volume V, Issue 213, 30 July 1887, Page 8

The Source of the Supply of Nitrogen.

Tiikre is a great deal of evidence which appears to support the theory that lugmninous plants, at least, derive a large amount of nitrogen from the atmosphere. Hitherto Sir John Lawes and Dr, Gilbert have been the strongest opponents of the theory, which they still hold to bo not proven. Professor Atwater, an American chemist, has rocently published a series of articles on tho subject, in the course ot which ho aigues that observations reported by Lawes and Gilbert in England, Deheran in Fiance, and Schulz-Lupitz in Germany, &ho\v that, after tho removal of heavy luguminoub crops, with their large quantities ot nitrogen, the soil was richer in nitiogen than before the crops weie sown. If tho plants derived all their niti'ogcn from the soil, he a&ks, how could the lat'cr havo more after producing them than before ? Sir John Lawes in reply says that what has Jjteu established at Rotham>tcad is tho fact that, after a clover crop has removed three or four times as much nitrogen a? a barley ciop growing in the same field, the tirst nine inches of the clover soil will contain (he larger amount of nitrogen of the twe ; but lie believe* it to be more likely that the surplus nitrogen has been brought up by the clover roots from the .-uibsoil than that it ha? bo p n derived from the atmosphere. Professor Atwater, how - evei, vefened to peas and beans as well as to clo\er.