IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Light and thermal environment as modified by a wheat crop throughout its cycle and effects on weed seed germination.
Autor/es:
BETINA KRUK,; PEDRO INSAUSTI; A RAZUL,; BENECH ARNOLD, R
Revista:
JOURNAL OF APPLIED ECOLOGY
Editorial:
Blackwell
Referencias:
Año: 2006 vol. 43 p. 227 - 236
ISSN:
0021-8901
Resumen:
Summary
1.Knowledge of the regulatory effects of the crop canopy on weed seed germination is
necessary to understand fully the behaviour of weed seed banks during a crop cycle. It
is well known that canopy presence interferes with seed germination through modifi-
cations to the light and thermal environment, but the changing effect of a growing
canopy has not been assessed, thus precluding the identification of shading-intensity
thresholds for triggering the different types of canopy-detection mechanisms in different
seed populations.
necessary to understand fully the behaviour of weed seed banks during a crop cycle. It
is well known that canopy presence interferes with seed germination through modifi-
cations to the light and thermal environment, but the changing effect of a growing
canopy has not been assessed, thus precluding the identification of shading-intensity
thresholds for triggering the different types of canopy-detection mechanisms in different
seed populations.
Knowledge of the regulatory effects of the crop canopy on weed seed germination is
necessary to understand fully the behaviour of weed seed banks during a crop cycle. It
is well known that canopy presence interferes with seed germination through modifi-
cations to the light and thermal environment, but the changing effect of a growing
canopy has not been assessed, thus precluding the identification of shading-intensity
thresholds for triggering the different types of canopy-detection mechanisms in different
seed populations.
2.Field experiments were performed with artificially modified thermal and light environments,
using two types of seed banks (seeds buried or located at the soil surface).
Conditions below a wheat canopy were modified to match light and thermal conditions
prevailing on bare soil (i.e. soil without vegetation).
using two types of seed banks (seeds buried or located at the soil surface).
Conditions below a wheat canopy were modified to match light and thermal conditions
prevailing on bare soil (i.e. soil without vegetation).
Field experiments were performed with artificially modified thermal and light environments,
using two types of seed banks (seeds buried or located at the soil surface).
Conditions below a wheat canopy were modified to match light and thermal conditions
prevailing on bare soil (i.e. soil without vegetation).
3.Most weed emergence patterns during the early stages of crop establishment were not
modified by the thermal regime produced by the incipient canopy compared with a bare
soil control. However, the reduction of the red : far-red ratio from the bare soil value of
1·20·9 below the wheat canopy reduced germination of some weed species located at
the soil surface, and the effect could by reversed by far-red filters.
modified by the thermal regime produced by the incipient canopy compared with a bare
soil control. However, the reduction of the red : far-red ratio from the bare soil value of
1·20·9 below the wheat canopy reduced germination of some weed species located at
the soil surface, and the effect could by reversed by far-red filters.
Most weed emergence patterns during the early stages of crop establishment were not
modified by the thermal regime produced by the incipient canopy compared with a bare
soil control. However, the reduction of the red : far-red ratio from the bare soil value of
1·20·9 below the wheat canopy reduced germination of some weed species located at
the soil surface, and the effect could by reversed by far-red filters.
4.The weedGalinsoga parvifloradeveloped two generations during the crop cycle. The
modified light and thermal environments beneath an establishing wheat canopy was not
sufficient to inhibit the germination ofGalinsoga parviflora, even if seeds were located at
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
modified light and thermal environments beneath an establishing wheat canopy was not
sufficient to inhibit the germination ofGalinsoga parviflora, even if seeds were located at
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
The weedGalinsoga parvifloradeveloped two generations during the crop cycle. The
modified light and thermal environments beneath an establishing wheat canopy was not
sufficient to inhibit the germination ofGalinsoga parviflora, even if seeds were located at
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
Galinsoga parviflora, even if seeds were located at
the soil surface. Only for seeds of the second generation, dispersed from seeds of the first
plant generation, was there sufficient modification of the photothermal environment
below the wheat canopy to interfere with dormancy termination.
5.Synthesis and applications. Understanding seed responses to modifications in the
photothermal environment below a crop canopy (e.g. wheat crop) should allow us to
improve weed management strategies by manipulating crop canopy attributes. This
could be achieved by modification of sowing date, crop density, spatial arrangement and
genotype. For example, increasing the crop plant density would diminish the number of
weeds emerging during the first phase of crop establishment. This strategy would be
appropriate where weed seeds are predominantly located at the soil surface, typically
found in a no-till cropping system.
photothermal environment below a crop canopy (e.g. wheat crop) should allow us to
improve weed management strategies by manipulating crop canopy attributes. This
could be achieved by modification of sowing date, crop density, spatial arrangement and
genotype. For example, increasing the crop plant density would diminish the number of
weeds emerging during the first phase of crop establishment. This strategy would be
appropriate where weed seeds are predominantly located at the soil surface, typically
found in a no-till cropping system.
Synthesis and applications. Understanding seed responses to modifications in the
photothermal environment below a crop canopy (e.g. wheat crop) should allow us to
improve weed management strategies by manipulating crop canopy attributes. This
could be achieved by modification of sowing date, crop density, spatial arrangement and
genotype. For example, increasing the crop plant density would diminish the number of
weeds emerging during the first phase of crop establishment. This strategy would be
appropriate where weed seeds are predominantly located at the soil surface, typically
found in a no-till cropping system.
Key-words: emergence patterns, establishing canopy,Galinsoga parvifloraCav., germination,light environment, thermal regime, weed seeds: emergence patterns, establishing canopy,Galinsoga parvifloraCav., germination,light environment, thermal regime, weed seeds