germination and seedling growth through the release of allelochemicals in the
rhizosphere [133, 134]. In addition, the use of allelopathic mulch can increase the
soil fertility and the soil organic matter, soil moisture, and soil water infiltration and
can influence the effects of raindrops on soil, thus altering the soil temperature,
activities of soil microbes with simultaneous reduction in soil erosion [135, 136].
Different rice weeds such as barnyard grass, flat sedge (Cyperus difformis L.) purple
nutsedge, and jungle rice were reduced by 70%, and paddy yield was enhanced by 20%
when the allelopathic plant mulch (1–2 t ha
À1
) was applied [137]. The annual weeds
such as common chickweed (Stellaria media L.), shepherd’s purse (Capsella bursapastoris L.), meadow grass (Poa annua L.), German chamomile, and henbit deadnettle
(Lamium amplexicaule L.) in wheat, sunflower, and maize were decreased when the soil
was amended with olive (Olea europaea L.) waste [138]. In addition, when purple
passion fruit (Passiflora edulis L.) was applied at 2 t ha
À1 as surface mulch in paddy
field, it enhanced the rice yield by 35% and decreased the density of monochoria
(Monochoria vaginalis L.) and barnyard grass than control treatment [139]. Similarly,
weeds such as barnyard grass and pickerel weed (Monochoria vaginalis (Burm. f.) C.
Presl.) were controlled by mulch of alfalfa (Medicago sativa L.) crop [137]. Use of
wheat residue as soil cover conserved the soil moisture and reduced the weed population
and biomass in broad bean (Vicia faba L.) [134]. In another study, mulching with wood
chip material efficiently inhibited the weed density and also increased the soil organic
matter and water-holding capacity of soil [140].
3.5
Use of Allelopathic Water Extracts
Allelochemicals when extracted in water from different parts of plant are also good
alternatives of herbicides for weed control (Table 3; [14, 145]). Several studies
conducted under the laboratory and field conditions revealed that weed density
and dry biomass were reduced by the use of allelopathic water extracts [77, 142,
145], especially the sorghum crop water extract [146].
As natural herbicide, sorghum is considered as one of the very commonly used
crops for water extract preparation. The horse purslane, field bindweed, Bermuda
grass, and purple nutsedge were reduced by 39.7, 58.4, 26.5, and 11.4 due to sorgaab
(sorghum water extract) application, respectively, in cotton [143]. Weeds of cotton,
sunflower, and mung bean are also controlled by sorgaab [147]. In wheat, weed
population is decreased, and grain yield is increased by the application of sorghum
extract extracts at various rates [146]. For example, weeds such as wild oat, littleseed
canarygrass, common lamb’s quarter, and field bindweed were controlled by application of sorghum water extract [115].
Various other studies have reported that weed population in wheat [115], rice
[148], cotton [12], maize [132], canola [77], and mung bean [116] was reduced by
18–44% by the application of sorghum water extract. In comparison to sole application of sorghum water extract, the combined application of sunflower, eucalyptus
(Eucalyptus camaldulensis Dehnh.), and sorghum water extracts was found to be
more efficient for the control of weeds in wheat fields [149]. Likewise, the
23 Ecological Management of Agricultural Pests Through Allelopathy
555
rhizosphere [133, 134]. In addition, the use of allelopathic mulch can increase the
soil fertility and the soil organic matter, soil moisture, and soil water infiltration and
can influence the effects of raindrops on soil, thus altering the soil temperature,
activities of soil microbes with simultaneous reduction in soil erosion [135, 136].
Different rice weeds such as barnyard grass, flat sedge (Cyperus difformis L.) purple
nutsedge, and jungle rice were reduced by 70%, and paddy yield was enhanced by 20%
when the allelopathic plant mulch (1–2 t ha
À1
) was applied [137]. The annual weeds
such as common chickweed (Stellaria media L.), shepherd’s purse (Capsella bursapastoris L.), meadow grass (Poa annua L.), German chamomile, and henbit deadnettle
(Lamium amplexicaule L.) in wheat, sunflower, and maize were decreased when the soil
was amended with olive (Olea europaea L.) waste [138]. In addition, when purple
passion fruit (Passiflora edulis L.) was applied at 2 t ha
À1 as surface mulch in paddy
field, it enhanced the rice yield by 35% and decreased the density of monochoria
(Monochoria vaginalis L.) and barnyard grass than control treatment [139]. Similarly,
weeds such as barnyard grass and pickerel weed (Monochoria vaginalis (Burm. f.) C.
Presl.) were controlled by mulch of alfalfa (Medicago sativa L.) crop [137]. Use of
wheat residue as soil cover conserved the soil moisture and reduced the weed population
and biomass in broad bean (Vicia faba L.) [134]. In another study, mulching with wood
chip material efficiently inhibited the weed density and also increased the soil organic
matter and water-holding capacity of soil [140].
3.5
Use of Allelopathic Water Extracts
Allelochemicals when extracted in water from different parts of plant are also good
alternatives of herbicides for weed control (Table 3; [14, 145]). Several studies
conducted under the laboratory and field conditions revealed that weed density
and dry biomass were reduced by the use of allelopathic water extracts [77, 142,
145], especially the sorghum crop water extract [146].
As natural herbicide, sorghum is considered as one of the very commonly used
crops for water extract preparation. The horse purslane, field bindweed, Bermuda
grass, and purple nutsedge were reduced by 39.7, 58.4, 26.5, and 11.4 due to sorgaab
(sorghum water extract) application, respectively, in cotton [143]. Weeds of cotton,
sunflower, and mung bean are also controlled by sorgaab [147]. In wheat, weed
population is decreased, and grain yield is increased by the application of sorghum
extract extracts at various rates [146]. For example, weeds such as wild oat, littleseed
canarygrass, common lamb’s quarter, and field bindweed were controlled by application of sorghum water extract [115].
Various other studies have reported that weed population in wheat [115], rice
[148], cotton [12], maize [132], canola [77], and mung bean [116] was reduced by
18–44% by the application of sorghum water extract. In comparison to sole application of sorghum water extract, the combined application of sunflower, eucalyptus
(Eucalyptus camaldulensis Dehnh.), and sorghum water extracts was found to be
more efficient for the control of weeds in wheat fields [149]. Likewise, the
23 Ecological Management of Agricultural Pests Through Allelopathy
555