In field experiments, P‐induced Zn deficiencies were observed in field corn in 1958 and in sweet corn, tomatoes and field corn in 1959. In greenhouse experiments with Red Kidney beans (Phaseolus vulgaris), severe P‐induced Zn deficiencies occurred with P fertilization. Zinc absorption was increased by Zn fertilization and decreased by P fertilization. Phosphorus uptake was increased with P fertilization and decreased by Zn fertilization. When both Zn and P were applied, the uptake of both Zn and P were reduced.

Synopsis In irrigated areas where a “plowsole” layer existed, a large percentage of plant roots were found to occupy the first foot of soil and especially the first 6 inches. The number and size distribution of roots per increment of soil depth gave a better comparison between different crops from the standpoint of soil physical properties than a comparison of root weights alone.

Phosphorus‐Zn interactions in fiber flax, Linum usitatissimum L., were studied in growth chambers by means of a two‐zone root technique and nutrient solutions. Zinc and P were added separately from each other and the other essential elements; therefore, any interactions that occurred between them or with other elements had to take place at root surfaces or within the plant.Increasing either Zn or P in the substrate increased the concentration and total uptake of the respective element in the roots and tops of the flax plants.When P was added first, Zn increased total P in the lower and upper roots and decreased total P in the tops. When Zn was added first, P increased total Zn in the lower roots and decreased total Zn in the tops.The results indicate that P and Zn react together within the roots in a manner that reduces either their mobility or solubility.

Synopsis In a field experiment with grain sorghum, applications of 60 and 120 pounds per acre of nitrogen gave significant increases in both content and yield of protein in the grain and forage. Apparent nitrogen recovery was 83.2 and 89.6%, respectively, when 60 and 120 pounds of nitrogen per acre were applied.

A hypothesis based on laboratory investigations is proposed to explain hardpan conditions which occur in cultivated and virgin soils in the Lower Rio Grande Valley. Hardpan formation, as influenced by various soil and moisture treatments, was evaluated. The hardpans produced in the laboratory were not of the intensity of field hardpans but were characteristically similar to those found in the field. The penetrometer was particularly adapted for evaluating the influence of laboratory treatments on hardpan formation. Moisture loss by evaporation, after surface drying, appears to be an important factor in formation of hardpans. Laboratory findings indicate that tillage practices influence the rate of moisture loss which influences the depth and intensity of hardpan formation in certain soils.