Greenhouse Experiments with Atmospheric Nitrogen Fertilizers and Related Compounds

In connection with a study at the Fixed Nitrogen Research Laboratory on the possible transformation products of cyanamid, there was obtained a number of materials and mixtures concerning which there is either very little known, or concerning which there is still some doubt as to their fertilizing value. Thus, in the preparation of urephos, a product was obtained in which approximately 55 per cent of the nitrogen was present as urea, 30 to 35 per cent as guanylurea, 5 per cent as ammonia, and the balance in undetermined forms, a small part of which was dicyanodiamide. There is very little data available on the use of guanylurea as a fertilizer, and the literature on cyanamide and especially on dicyanodiamide contains many conflicting statements. The experiments reported here deal with these nitrogenous materials, as well as others, such as sodium nitrate and calcium nitrate, included for comparison. In addition, a few experiments were included in which calcium sulphate, potassium sulphate, and acid phosphate, but no nitrogen compounds, were added. A portion (Table I) of the experimental work was conducted in 1919, but a later group (Table 11) of pot tests was conducted during the early part of 1922.