Submitted to: Journal of Environmental Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2000
Publication Date: N/A
Interpretive Summary: Experiments were conducted to determine the effects of using pelletized recycle paper mulch in plants grown in containers in the nursery industry. The objective of the study was to determine if the use of the pelletized paper could reduce nutrient losses from water flowing through the containers. While some plant growth reductions were observed, incorporation of fertilizer into the pelletized paper mulch reduced the fertilizer nitrogen in the water flowing through the pots by as much as 87%. This research suggest that the use of pelletized paper may be able to reduce nitrogen losses to the environment of horticulture plants during growth in nurseries, but also provide a nitrogen rich environment for initiating growth when plants are planted into landscapes.
Technical Abstract: Two experiments were conducted to determine the effects of pelletized recycled paper mulch on container plant nutrition. In experiment I with Petunia floribunda Hort. 'Midnight Madness', 9 g of Osmocote 14N-6.2P- 11.6K was applied over or under 2.5 cm of recycled paper pellet mulch, or to plants with no paper mulch. Leachate samples were collected after microirrigation. Both treatments with paper mulch reduced nitrate and ammonium levels in container leachate, compared to the control. Shoot dry weight was reduced 53% and 70% for plants fertilized under and over the mulch respectively. At the end of the experiment 40-48% of the total N applied over or under mulch was retained by the recycled paper mulch. In experiment 2 with Petunia grandiflora Hort. 'Ultra Blue', mulch and three methods of fertilizer application (over mulch, under mulch, and incorporated) were compared. Leachate nitrate levels were reduced 72% or 68% with fertilizer placed over or under the mulch, respectively. When fertilizer was incorporated into the substrate, paper mulch reduced shoot dry weight 41% when compared to non-mulched plants, however, paper mulch also reduced nitrate leachate levels 87% and ammonium levels 82% compared to the non-mulched control.