The Effect of the Addition of Vama to Soil upon Uptake of Phosphorus and the Utilization of Phosphorus Applied in Fertilizer by the Oat Plant

endothal at the early date was made at a critical time of rapid seed formation; thus the yield of seed was decidedly lowered within a five-day period. The average yield of seed was greater for the untreated plots than for the treated, and the largest yield of seed was obtained at a harvesting interval of 3 days following treatment. These data were consistent with those given for 2 dates of spraying with 2 to 6 quarts of endothal. Table 3 shows that a loss of moisture occurred in all treated plots. The greatest loss occurred from the first to the third day after treatment. The loss between the third and fifth days was relatively less. Increasing concentrations of endothal per acre caused a progressive decrease in moisture except for the 4-quart rate at the 5-day interval of sampling. Data for the spraying made on July 29 are not shown, but differences were of the same order except that a greater reduction in moisture occurred. This was probably due to differences in weather conditions at the two dates of spraying and also to the greater succulence of the Ladino clover at the earlier date. While these results are based on only 1 year's data and are not conclusive, they do seem to indicate that later harvest dates may give higher seed yields, and that treatment with endothal may increase the speed and ease of harvesting by lowering the moisture content.—M. A. MASSENGALE, and J. T. MEDLER, Research Assistant and Associate Professor, Departments of Agronomy and Entomology, respectively, University of Wisconsin.