Management of Herbicide and Fertility Levels on Weeds and Kentucky Bluegrass Turf1
- B. J. Johnson and
- T. H. Bowyer2
To maintain a good quality weed-free turf, it is usually necessary to apply herbicides for weed control and fertilizer for turfgrass growth. It may be possible to substitute a specific amount of fertilizer for herbicides in maintaining a good quality turf. A field experiment was conducted in Kentucky bluegrass (Poa pratensis L. ‘Common’) turf on Congaree loam (Fluventic Dystrochrepts) at Blairsville, Ga. to determine minimum herbicide and fertilizer combination treatments needed for effective weed control and turfgrass quality.
Nitrogen (N) and preemergence herbicides applied to the same plots for 4 consecutive years controlled a higher percentage of large crabgrass [Digitaria sanguinalis (L.) Scop.] than when either was applied alone. However, MSMA (monosodium methanearsonate) controlled large crabgrass effectively whether the chemical was applied to plots treated with N or to plots receiving no fertilizer. Dandelions (Taraxacum officinale Weber) were effectively controlled with MSMA. When MSMA was not used, dandelion control was generally greater in plots treated with 6 kg N/are than when treated with 3 kg N/are. In 1 of 4 years, Kentucky bluegrass was severely injured by combination treatments of MSMA with either isobutylidene diurea (IBDU), ureaformaldehyde (UF), or sulfur-coated urea (SCU). The injury was not as severe when MSMA was applied alone or with ammonium nitrate (AN). There was less red thread disease [Corticuim fuciforme (Berk.) Wakef.] in plots treated with MSMA than in those treated with preemergence herbicides. After 4 years, there was generally less disease in AN treated plots than in the slow release N treated plots. However, the turf had less red thread disease in plots where 6 kg/are of slow release N was applied than in plots where only 3 kg N/are was applied.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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