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Fishwaste Compost Effects on Rhododendron Growth and Nitrogen Leaching and Transformation
Author(s) -
Kuo S.,
Hummel R. L.,
Jellum E. J.,
Privett D.
Publication year - 1997
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1997.00472425002600030019x
Subject(s) - compost , chemistry , leaching (pedology) , leachate , fertilizer , nitrogen , transplanting , botany , agronomy , environmental chemistry , biology , soil water , organic chemistry , ecology , seedling
Availability and leachability of N in fishwaste compost should be considered before it is used as growing media for nursery stock. This study examined N availability and leaching, and transformation of organic N constituents in fishwaste compost (HGF) as well as the effect of the compost on growth of rhododendron ( Rhododendron fortunei ‘Scintillation’). With an initially high inorganic N concentration, the compost enhanced growth of rhododendron during its first flush of growth. Because of extensive N leaching, this beneficial effect was short‐lived. Periodic additions of N fertilizer at 150 mg N kg −1 were required to improve growth of rhododendron. Approximately 45% of inorganic N present initially in the HGF was leached regardless of the proportions of HGF in the mixtures. With N uptake by the plants representing a small fraction of inorganic N added, the inorganic N lost not accounted for probably was lost by denitrification and/or ammonia volatilization. Most N fertilizer applied as NH 4 NO 3 to 100% bark was also leached. Concentrations of labile amino acids changed significantly in 4 mo, from 53.6% to <5% of total organic N in the HGF. Similar reduction also occurred for amino sugars. Even with such a magnitude of change in the two labile N fractions, there was no marked increase in inorganic N in the leachate 2 wk after transplanting and in growth of rhododendron. A large proportion of amino acids and amino sugars present in the compost initially were probably transformed to a more stabilized organic N form.