Nitrogen deficiency (needle chlorosis) in white spruce planted in poorly-drained old field sandy loams. Larose Forest, Limerick

Nitrogen fertilization trial A-60-N1, control on left, 100k/ha on right. White spruce, 2+0, fertilization trials.

Nitrogen fertilization trial N @ 300lb/ac as ammonium sulphate, one of the first such trials in Ontario. White spruce, 1+0, fertilization.

Nitrogen-deficient Norway spruce one year after planting (cf.#74). Dorset.

Nitrogen-deficient white spruce furrow planted in an old field. Nr. Parry Sound

Nitrogen-fixing nodules on Alnus; actinomycetes the organisms. Spodosol, HF, BSY.

No sawdust added, n.b. large seedlings and green colour.cf#45. Jack pine, 1+0, sawdust not added to soil.

Noble fir grown in large "wood" tubes. Noble fir, 1+0, container.

Nodules from roots of Alnus glutinosa in Dorset area; n.b. scale

Nodules of Comptonia peregrina N-fixing