RESPONSES OF LEYMUS-ARENARIUS TO NUTRIENTS - IMPROVEMENT OF SEED PRODUCTION AND SEEDLING ESTABLISHMENT FOR LAND RECLAMATION

Citation
S. Greipsson et Aj. Davy, RESPONSES OF LEYMUS-ARENARIUS TO NUTRIENTS - IMPROVEMENT OF SEED PRODUCTION AND SEEDLING ESTABLISHMENT FOR LAND RECLAMATION, Journal of Applied Ecology, 34(5), 1997, pp. 1165-1176
Citations number
35
Categorie Soggetti
Ecology
Journal title
ISSN journal
00218901
Volume
34
Issue
5
Year of publication
1997
Pages
1165 - 1176
Database
ISI
SICI code
0021-8901(1997)34:5<1165:ROLTN->2.0.ZU;2-L
Abstract
1. Iceland has vast areas of mobile sand resulting from volcanic glaci er bursts and erosion. Seed of the coastal, dune-building grass Leymus arenarius is harvested from natural stands for use in extensive land reclamation programmes. We investigated the economic use of fertilizer treatments in managing the production of seeds, and to facilitate the establishment and survival of seedlings. 2. Seed yield could be incre ased dramatically-in coastal dunes by the application of nitrogen fert ilizers, mainly as a result of increased flowering-spike density. Litt le short-term advantage accrued from additions of phosphorus or potass ium. Additions of N (rapid-release formulations) at 50-100 kg ha(-1) c ould be highly cost-effective in providing the current production from a much smaller area of dunes or in increasing seed production. Other consequences would be to minimize the environmental impact of harvesti ng and to allow more focused management of the seed resource. If perio dic applications of P and K should prove necessary to maintain yield, they would be economically justifiable. 3. Establishment of seedlings on volcanic, sandy barrens over the first two seasons from sowing was improved by the application of slow-release fertilizers; however, rapi d-release formulations applied annually, produced a similar tiller den sity and biomass after 4 years more economically. Untreated control po pulations became extinct over the same period, underlining the necessi ty for nutrient addition. A sand-culture experiment indicated that pla nts severely deprived of P allocated more dry mass to roots and rhizom es, and those deprived of K allocated more to above-ground parts. Thes e responses might be manipulated to improve establishment in slowly an d rapidly accreting environments, respectively. 4. The seed production of moribund, late-successional stands could not be rejuvenated by fer tilizer application. On the contrary, where there was a vegetational r esponse, competing species were stimulated at the expense of L. arenar ius.