The foliar absorption of urea‐N by tall fescue and creeping bentgrass turf

Abstract

The absorption and assimilation of ¹⁵N‐labeled urea applied to the foliage of tall fescue (Festuca arundinacea Schreb.) and creeping bentgrass (Agrostis palustris Huds.) turf was examined under a controlled environment. Each source of N was dissolved in deionized water to a final concentration of 25 g N liter^‐1 and spray‐applied at a rate of 5 g N m^‐2. Absorption of the fertilizer‐N over a 72 hr period, as measured by ¹⁵N analysis of tissue digests, averaged 55% for the two species. Absorption was also estimated by a washing procedure which measured the urea remaining on the foliage, and by the increase in total N in the plant tissue.

There were no significant differences between the three methods in estimating absorption. Partitioning of the absorbed ¹⁵n between tissues averaged 37% in new leaves, 51% in old leaves and shoot tissue, and 11% in the roots. More than 90% of the absorbed urea‐N was hydrolyzed by 72 hr.

Notes

Department of Environmental Horticulture, University of California, Davis, CA 95616