The foliar absorption of urea-N by Kentucky bluegrass turf
1989
Bowman, D.C. | Paul, J.L.
The absorption and assimilation of urea applied to the foliage of Kentucky bluegrass (Poa pratensis L. 'Columbia') turf was evaluated under a controlled environment. Urea was spray-applied at 5 g N m-2 in 200 ml m-2 of deionized water to both N-replete and N-deficient turf. Uptake over a 48 hr period was estimated by a washing procedure to measure the urea remaining on the foliage and by 15N analysis. Immediately following application, approximately one third of the urea was located on new leaf blades and two thirds on older leaves and shoots. Compared to the amount of urea absorbed at 48 hr as determined by 15N analysis (43%), the washing method significantly overestimated urea absorption (59%). Approximately 30%, 55%, and 15% of the absorbed 15N-urea was recovered in the new leaves, old leaves/shoots, and roots, respectively. Nitrogen deficiency had very little effect on either urea absorption or partitioning of the absorbed N. Because approximately 40% of the urea remained on leaf blades 48 hr after application, considerable loss of the fertilizer N might occur with mowing and clipping removal.
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