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- Author or Editor: R. L. Branson x
- Journal of the American Society for Horticultural Science x
Abstract
A greenhouse experiment was conducted using ornamental privet plants (Ligustrum japonicum Thunb.) to determine the effects of irrigation treatment (daily vs. every 2 days), container type (plastic vs. clay), and mix (redwood-sand; pine-sand; pine-soil; or sphagnum peat-perlite-sand) on the fate of applied N. The sinks for N that could be accounted for consisted of uptake by plants, N absorbed and/or adsorbed by the mix and container, and N leached. Growth rate and uptake of applied N was greatest for plants in plastic containers which were irrigated daily. The type of mix used did not appear to significantly affect plant growth. Compared with all other treatments, larger proportions of the applied N were absorbed and/or adsorbed by redwood-sand or pine-sand mixes in plastic containers irrigated on alternate days. Larger proportions of applied N were lost in leachate water from plastic containers that were irrigated daily than all of the other treatment variables. Unaccounted-for N (denitrified) was greater for plastic containers (16.2%) than clay containers (10.8%), and pine mixes had significantly greater proportions of applied N denitrified (17.7% for pine-sand and 18.9% for pine-soil) than redwood (9.3%) or peat (8.1%).
Abstract
Peat-sand (1:1, by volume) and wood-sand (2:1, by volume) mixes in 10 cm plastic pots were planted with Epipremnum aureum Linden & Andre cv. Tricolor (pothos), Coleus glumei Benth (coleus), and Brassaia actinophylla Endl. (schefflera). After the pH of the leachate had dropped to between 4.0 and 5.0, pots received a single irrigation with solutions NaHCO3 and KHCO3. For the peat mix, the highest concentrations (0.20 M) of NaHCO3 and KHCO3 raised the leachate pH to nearly 9.0; the pH subsequently dropped most rapidly in pots containing coleus and schefflera, and slowest with pothos. In pots containing the wood-sand mix, the pH climbed as high as 8.0 immediately after treatment with 0.08 m KHCO3, then decreased slowly in pothos and more rapidly with the other 2 species. In peat mixes, the final leachate pH was nearly one unit greater than the saturation paste pH of the soil. In wood-sand pots, mix from the bottom half of the pot was always lower in pH than mix from the top half. Except for schefflera the pH of the last leachate obtained was nearer the pH of the bottom half of the pot than that of the top half.