Mineralization of N from Several Sources and Establishment of ‘Penncross’ Creeping Bentgrass on Putting Green Media1
- A. R. Mazur and
- C. B. White2
The practice of using little if any soil in putting green mixtures combined with the annual application of large quantities of N fertilizer provides a high potential for loss of N through leaching. Studies were conducted on two putting green media with and without soil [70% (vol.) sand + 20% peat + 10% Cecil sandy loam and 70% sand + 30% peat] to 1) investigate the nitrifier and denitrifier populations; 2) measure the mineralization products of ureaformaldehyde (UF), sulfur-coated urea (SCU), isobutylidene diurea (IBDU), and urea under both laboratory and field conditions; and 3) determine the leaching losses and rate of ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) establishment with the respective N source materials. Initially the mixture containing soil had Nitrosomonas and Nitrobacter populations 490 × and 41.5 × higher, respectively, than the mixture without soil. In the field studies no treatment differences were found in nitrifying bacteria populations after 1 month. Little if any urea-N or NH4+-N was found in the leachate samples. The influence of percolating water was most evident on leaching losses with SCU and IBDU in the soilless media. The establishment of bentgrass was most rapid with the IBDU treatment in the mixture containing soil with 50% coverage 4 weeks after seeding and 83% coverage after 9 weeks. Even in the soilless mixture establishment rate of bentgrass was greater at 4 weeks with IBDU (22%) than with urea (7%) or UF (8%) but not significantly greater than SCU (18%).Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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