Bermudagrass Response to Reactive Layer Coated Fertilizers

Abstract

Abstract Recent polymer chemistry research has introduced a material manufactured by a reactive layer coating (RLC) process which shows promise for minimizing N loss through leaching. Laboratory studies have shown that RLC coated ureas were successful at slowing N release and have potential as slow‐release N fertilizers for turf. This field study compared ‘Tifway’ bermudagrass ( Cynodon dactylon L. Pers. ✕ C. transvaalensis Burtt‐Davey) response to RLC ureas having different coating weights (thicknesses) with other conventional N carriers. Bermudagrass turf quality (1 – 9 scale, 9 = best) and shoot growth response observations were made over a 10‐wk period to determine if various coating thicknesses would allow adequate N release to provide a response equivalent to other N sources. Best turf quality (7.4) for the 2‐yr study was for RLC carriers that combined slow and intermediate release rate RLC ureas (12.5% or 10.8% coating + 7.2% coating) with urea. Overall turf quality was lowest (6.5) in 1987 for the RLC with the slowest release rate, a 12.5% coating (10 g N m −2 ), 9.9% RLC coating + urea (10 g N m −2 ), and urea (5 g N m −2 ). In 1988 the RLC with the slowest release had a 10.8% coating (10 g N m −2 ). Shoot growth rate in 1987 was greatest (11.9 mm wk −1 ) for the RLC material with a 7.2% coating at 10 g N m −2 and lowest for the RLC 12.5% coating (5.3 mm wk −1 ). By comparison, urea applied at 5 g N m −2 resulted in intermediate turf growth (9.4 mm wk −1 ). In 1988, shoot growth rate was greatest for the 10.8% RLC + 7.2% RLC + urea combination material applied at 10 g N m −2 . Equivalent growth was noted for the urea + 9.9% RLC (5g n m −2 ) and sulfur coated urea (10 g N m −2 ) materials. Use of slow release RLC N carriers as turf fertilizers showed promise as a combination material with urea.