NITROGEN AND LEGUMES.

New Zealand Herald, Volume LXVII, Issue 20679, 26 September 1930, Page 17

NITROGEN AND LEGUMES.

EFFECTS ON LUCERNE. HELPING SEEDLINGS. Thcio is a general impression in this country that .it is unnecessary to apply nitrogen in the form of artificial fertilisers to leguminous crops such as lucerne, the assumption being that those crops obtain all their nitrogen requirements from the air by means of the nodules on tlioir roots. It has been found, however, in very oarofully conducted experiments that nodulo formation, and thercforo tho fixation of nitrogen from tho atmosphere, does not begin in tho caso of lucerne until two to three months after sowing. In tho first year lucerne can utilise a relatively large amount of applied nitl'Ogen, because tho protein or nitrogencontent of the seed is not large enough to keep it over tho so-called hunger stage, and is unable to provide <i sufficient development of the root system for nitrogen fixation. Applied nitrogon is also helpful at the beginning of the first production year. It is obvious that unless the plant produces a fairly largo root system thcro can bo no largo development of nodules, sinco there will be only a small number of rootlets on which tho nodules can form Nitrogenous fertilisers aro extremely valuable in tho early stages of development of plants such as lucerne and beans. This has been confirmed repoatedly in practico by farmers who a small quantity of sulphate of ammonia or uitrochalk to their beans, thus giving them a good start in life and helping them to produce an extensive root-system. Even in tho later years of its development an appreciable amount of nitrogen is necessary to enable lucerne to produce its maximum yield, and this is especially the caso if the crop receives any injury in tbe early stages of growth.