INFLUENCE OF SOIL TEXTURE, REACTION, AND TEMPERATURE ON THE UPTAKE OF NITROGEN FROM THREE NITROGEN FERTILIZERS

Abstract

Rye grass was grown on four soils varying in texture and pH, in half-gallon glazed pots for a period of 8 months in the greenhouse. A 6-week cool period at 35° F. was employed following the first cutting. Nitrogen was top-dressed at the rate of 80 lb. nitrogen/ac., in the form of either urea, ammonium sulphate or calcium nitrate. These materials were added after germination of the ryegrass in one treatment, and beginning the cool period in a second treatment.From 50 to 100 per cent of the added nitrogen was recovered in plant material and leachates. Calcium nitrate gave the highest recovery of nitrogen on all soils. No difference was found between ammonium sulphate and urea in the uptake and leaching of nitrogen. Urea was converted to ammonia, at temperatures as low as 35° F. The application of nitrogen before the cooling period extended the period of uptake by the crop.It was concluded that the behaviour of nitrogen fertilizers in soil is dependent on both the texture and reaction of the soil, that the movement of urea in soil is small, and that the time of application influences the subsequent utilization of these materials by the crop.