Aqueous extracts contain humic acid and fulvic acid along with saccharides, alcohols, organic acids, and phenols. Study showed that different concentrations of
extract have different effects on different activities. Low concentration improved
Chlorella vulgaris chlorophyll fluorescence yield and growth rate, while high
concentration has an inhibitory effect on the growth and photosynthetic effects of
both soil microalgae. In a similar way, research study reported the allelopathic effect
of different solvent extracts of Pinus roxburghii (pine tree) against various types of
weeds such as Euphorbia helioscopia, Avena fatua, Phalaris minor, Chenopodium
album, Triticum aestivum, and Rumex dentatus [76]. Methanolic needle extract
possessed the maximum percentage inhibition effect on germination of Triticum
aestivum, followed by Chenopodium album and Avena fatua applied in soil.
3
Application of Allelopathy
Allelopathy has both beneficial and harmful effects. Negative effects of allelopathy
include autotoxicity, soil sickness, or biological invasion, while the positive effects
are weed control, crop protection, and so on. Currently various investigators are
working hard to use allelochemicals as growth regulators, herbicides, insecticides,
and antimicrobial crop protection products, and many of them are successful.
Following are some of the major application of plant allelopathy.
3.1
Weed Management
3.1.1 Intercropping
Weeds have become one of the major causes for losses in crop production due
to various reasons which include cost of weed management, weed crop competition,
and intervention of weeds with crop management practices [77–80]. The process
of growing crops in the same field at the same time is known as intercropping and
can be used for weed management [79]. Research investigation proved that
intercropping of allelopathic crops can be useful for weed management, mostly
in low absorption agriculture systems [81, 82]. Release of allelochemical, shade effect,
and weed-crop competition are the factors by which allelopathic intercrops suppress
weed growth [82–84]. Beside this, intercropping has other benefits like enhanced crop
yield, great use of resources, and exploitive effects on pests and insect. To increase the
crop production, weed management has become very important. A number of weed
management approaches are reported by authors to increase crop production [85, 86].
3.1.2 Mulching
In this process plant residue or crop residue is applied to the surface of
soil to improve soil fertility and soil moisture and to reduce weed growth. Chemicals
released by mulching process inhibit germination and seedling growth of weeds
[87–90]. Effect of sorghum mulch was studied by many researchers, for example,
26–37% of weed control was achieved by using sorghum mulch (10–15 t ha
À1 ) in
452
A. Bachheti et al.
extract have different effects on different activities. Low concentration improved
Chlorella vulgaris chlorophyll fluorescence yield and growth rate, while high
concentration has an inhibitory effect on the growth and photosynthetic effects of
both soil microalgae. In a similar way, research study reported the allelopathic effect
of different solvent extracts of Pinus roxburghii (pine tree) against various types of
weeds such as Euphorbia helioscopia, Avena fatua, Phalaris minor, Chenopodium
album, Triticum aestivum, and Rumex dentatus [76]. Methanolic needle extract
possessed the maximum percentage inhibition effect on germination of Triticum
aestivum, followed by Chenopodium album and Avena fatua applied in soil.
3
Application of Allelopathy
Allelopathy has both beneficial and harmful effects. Negative effects of allelopathy
include autotoxicity, soil sickness, or biological invasion, while the positive effects
are weed control, crop protection, and so on. Currently various investigators are
working hard to use allelochemicals as growth regulators, herbicides, insecticides,
and antimicrobial crop protection products, and many of them are successful.
Following are some of the major application of plant allelopathy.
3.1
Weed Management
3.1.1 Intercropping
Weeds have become one of the major causes for losses in crop production due
to various reasons which include cost of weed management, weed crop competition,
and intervention of weeds with crop management practices [77–80]. The process
of growing crops in the same field at the same time is known as intercropping and
can be used for weed management [79]. Research investigation proved that
intercropping of allelopathic crops can be useful for weed management, mostly
in low absorption agriculture systems [81, 82]. Release of allelochemical, shade effect,
and weed-crop competition are the factors by which allelopathic intercrops suppress
weed growth [82–84]. Beside this, intercropping has other benefits like enhanced crop
yield, great use of resources, and exploitive effects on pests and insect. To increase the
crop production, weed management has become very important. A number of weed
management approaches are reported by authors to increase crop production [85, 86].
3.1.2 Mulching
In this process plant residue or crop residue is applied to the surface of
soil to improve soil fertility and soil moisture and to reduce weed growth. Chemicals
released by mulching process inhibit germination and seedling growth of weeds
[87–90]. Effect of sorghum mulch was studied by many researchers, for example,
26–37% of weed control was achieved by using sorghum mulch (10–15 t ha
À1 ) in
452
A. Bachheti et al.