The Effect of Mulch Type and Fertilizer Placement on Marigold (Tagetes erecta `Hybrid Gold') Growth in Landscape Plantings

in HortScience
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  • 1 Department of Horticulture, University of Arkansas, Fayetteville, AR 72701

The objective of this study was to examine the influence of mulch material and fertilizer application method on nutrient availability in a landscape situation. Beds containing four mulch materials (pine bark, cypress pulp, pine straw, and cottonseed hulls) and three fertilizer application methods (granule, liquid, and time release) were established. Fertilizer placement included application either above or below the mulch horizon. Beds with and without mulch cover and no fertilization were established as controls. Marigolds, Tagetes erecta `Hybrid Gold', were planted within the beds. Plants in unmulched or fertilized control beds had greater dry weights than plants in beds with mulch alone. Only plants grown in the cottonseed hull control demonstrated a slight improvement and cottonseed hulls demonstrated the best plant performance overall. The greater nitrogen content of cottonseed hulls may influence less immobilization of nitrogen in the soil solution during decomposition and reduce competition for nutrients between microorganisms and plants. Fertilization improved plant growth in all treatments except pine bark. Beds using pine bark showed significant reduction in plant dry matter accumulation. Potential toxicity or changes in soil chemistry by pine bark may have influenced these results and will be examined in further experiments. Fertilizer placement had no effect on plant growth.