The effect of temperature, soil moisture, and methods of application on the loss of ammonia from solutions of ammonium nitrate and ammonia in water have been measured in the laboratory and by wheat yields in the field. The loss of ammonia was increased as soil moisture was lowered and temperatures were raised. Losses were less when applied on soil than on crop residues. These solutions gave increases in wheat yields equivalent to solid forms of nitrogen when applied under the surface of the ground.

Two trials of the effect of urea on wool production of Merino sheep were conducted in north-western Queensland. The urea was incorporated in compressed rations containing ground wheat and molasses, or ground wheat, bloodmeal and molasses, or was given as a mixture with molasses. These supplements were given thrice-weekly and, depending on the one used, the amount of urea offered on each occasion ranged from 25g. to 45g. In general, the urea-containing rations were not palatable. Each of the urea supplements in the amount given was toxic. The feeding of urea did not lead to increased wool production.

Permanent fertility studies were set up on the Agronomy Farm of Kansas State College in 1909 to determine the long-time effects of crop rotations and of soil treatments on the productive capacity of the soil. Trends in soil productivity induced by the different rotations and the different soil treatments were analyzed for the 42-year period 1911 through 1952. The analysis showed that, despite improved wheat varieties used during the investigations, the yields of unfertilized wheat and of unfertilized corn were maintained only in a 16-year rotation. Legume yields were not maintained in any rotation studied. Wheat yields indicate how various combinations of commercial fertilizers, rock phosphate, lime, and manure increased the productive capacity of the soil. Corn yields indicate that only treatments including nitrogen increased soil productivity for this crop. Soil treatments increased alfalfa yields. Alfalfa yields, however, were not maintained at the original level by any soil treatment.

Greenhouse and field studies were undertaken to evaluate the effect of the water-soluble phosphorus content and particle size of mixed fertilizers on the availability of fertilizer phosphorus to plants. Supplementary laboratory experiments were conducted to study the behavior of phosphorus in granulated mixed fertilizers under various soil conditions. The rate at which the water-soluble fraction of phosphorus moved out of fertilizer granules was rapid, essentially being complete in 48 hours. No important difference in dissolution rate was noted for fertilizers with varying water-soluble phosphorus contents over the range of 3.3 to 15% moisture. The extent of movement of fertilizer phosphorus away from large granules and the concentration in soil around the phosphate was directly related to the percentage of water-soluble phosphorus in the fertilizer. Varying the water-solubility of phosphate fertilizer having a similar N-P₂O₅-K₂O ratio had no significant effect on dry weight yield of wheat plants grown in the greenhouse. The percentage of plant phosphorus derived from fertilizer was markedly influenced by the water-soluble phosphorus content and the particle size of the mixed fertilizer and soil reaction. Absorption of fertilizer phosphorus by wheat plants from 4–6 mesh granular material was directly proportional to its water soluble phosphorus content. For pulverant fertilizers the phosphorus water solubility had very little effect on the percentage of plant phosphorus derived from fertilizer. At a soil pH of 5.5, wheat absorbed a larger quantity of fertilizer phosphorus than when grown at pH 6.5 or 7.5. The phosphorus content of field grown sugar beet plants was significantly higher 1 month after planting on plots where fertilizers high in water-soluble phosphorus were used as compared to those from plots treated with fertilizers low in water-soluble phosphorus. Two months after planting, values for total phosphorus were similar for plant samples from plots receiving fertilizers either high or low in water-soluble phosphorus. Although the yield response to phosphorus was highly significant, there were no significant differences in sugar beet yields between fertilizer treatments.