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STUDIES ON CROP-WEED ASSOCIATION UNDER DIFFERENT CROP ROTATIONS

KrishiKosh

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Title STUDIES ON CROP-WEED ASSOCIATION UNDER DIFFERENT CROP ROTATIONS
 
Creator GANGADHAR, B
 
Contributor KONDAP, S.M
 
Subject STUDIES, CROP-WEED, ASSOCIATION, UNDER, DIFFERENT, CROP, ROTATIONS,
 
Description In order to study the crop-weed association,
weed spectrum and density and the effect of crop
rotation on weeds and crops, a field experiment was
conducted on a sandy clay loam soil belonging to College
Farm, Hyderabad during three seasons (rabi 1986-87,
kharif 1987 and rabi 1987-88). The experiment was laid
out in split-plot design with 20 treatments, each
replicated thrice. The treatments consisted of two
types of weeding (no weeding and weed free) in main
plots and ten crop rotations (No crop, wheat/castor/
wheat, safflower/maize/safflower, chickpea/cowpea/
chickpea, safflower/castor/chickpea, chickpea/maize/
wheat, wheat/castor/safflower, chickpea/cowpea/
safflower, wheat/maize/chickpea and safflower/cowpea/
wheat) in sub-plots.
In first season out of 23 weed species, in
third season out of 24 weed species observed,
Trichodesma indicum, Melilotus alba, Chenopodium album,
Euphorbia geniculata, Lagascea mollis, Cypsrus
rotundus, Digera arvensis, Echinocloa crus-galli,
Argemone mexicana and Cynodon dactylon were dominant.
During second season, out of 10 weed species observed,
Rottboellia exaltata, Cyperus rotundus, Euphorbia
geniculata, Digera arvensis and Lagascea mollis were
dominant. These species recorded more frequency and
relative density.
The weed species, Helilotus alba, Chenopodium
album, Argemone mexicana and £chinocloa crus-galli were
present only during first and third · seasons. While
during season these were absent.
Among the dominant weeds, Trichodesma indicum
during first and third seasons, Rottboellia exaltata
during second season were very prominent weed species.
The total density and dry weight of weeds
decreased during t hird season c ompa r ed to first season.
But the least density was noticed i n second season.
During second season the dry we i ght o f weeds was very
high even though the weed density was very less
indicating the vigorous g r owth o f weeds during second
season (khari f 1987). The weed density was maximum at
60 DAS but the d r y weight of weeds was maximum at 90
DAS during three seasons.
The weed density and dry weight of weeds were
reduced in third season compared to first season due to
crop rotations. The crop rotations involving cowpea
during second season recorded highest per cent
reduction in weed density and dry weight of weeds. The
highest grain yiel d , dry matter production of crops and
test weight were also recorded in the crop rotations
involving cowpea during second and third seasons.
Growing smothering crops like cowpea in crop
rotation reduced the weed growth and gave highest
yields. Of all the crop relations studied, the crop
rota tions chickpea/cowpea/safflower, chickpea/cowpea/
c hickpea and safflower/cowpea/wheat gave significantly
higher yields.
 
Date 2016-08-06T13:09:19Z
2016-08-06T13:09:19Z
1989
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/71242
 
Language en
 
Relation D3099;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD