Huang, W. 1998.
Productive coexistence and gain in agroforestry systems
Acta Forestalia Fennica 260. 72 p.
[ Acta Forestalia Fennica
- Productive coexistence and coexistence gain of populations
were studied using nine years' data from field experiments of
Taxodium ascendens-intercrop systems in Lixiahe,
Jiangsu Province, China. A theoretical framework for productive
coexistence in agroforestry was developed. Interaction patterns
between trees and intercrops were presented within this framework.
A model framework was developed to describe the coexistence gain
and interaction of populations in T. ascendens-intercrop
systems. Facilitation and resource sharing were identified as
main contribution to the advantage of species combination in
agroforestry. The model of population interaction developed in
the present study was accepted for describing the interaction
of populations in T. ascendens-intercrop systems,
because it explained a high proportion of the variance of experimental
data and fitted well the observations in most intercropping types.
The model developed in the present study provides flexibility
for describing different patterns of intra- and inter-specific
interactions. Model coefficients were applied to the determination
of the ecological compatibility of species.
- Managed T. ascendens-intercrop systems were
advantageous as compared to a monoculture of trees or arable
crops. In T. ascendens stands up to the age of
three, arable crops contributed about 50-80 % of the total biomass
yield of agroforestry. The diameter or height growth of T.
ascendens was not significantly influenced by intercrops,
indicating that intercropping under trees produced extra yields
but did not depress the tree growth. When the trees were young
(during the first three years), T. ascendens did
not depress the crop yields, and a land equivalent ratio greater
than unity was obtained together with a high yield of both components.
The diameter and height of the trees were similar in four spacing
configurations with an equal number of trees per hectare up to
the age of eight, but wider between-rows open range were beneficial
for the intercrops. The relationship between open-ranges and
species coexistence was also analysed and the distribution of
soil nutrients studied.
agroforestry, coexistence gain, facilitation, interaction model,
productive coexistence, resource sharing, Taxodium ascenden
- Author's address
Department of Forest Ecology/Tropical Silviculture, P. O. Box
28, FIN-00014 University of Helsinki, Finland. Fax +358 9 708
5646, E-mail email@example.com
- ISBN 951-40-1603-3