TY  - BOOK
AU  - Ameena M
AU  - Sansamma George (Guide)
TI  - Investigation on allelopathic influence and control of purple nuts edge
U1  - 630 
PY  - 1999///
CY  - Vellayani
PB  - Department of Agronomy, College of Agriculture
N2  - Lab and field experiments were conducted at the Instructional 
farm, College of Agriculture, Vellayani to study the allelopathic influence of 
Purple nutsedge (Cyperus rotund us L) on important field crops; to investigate 
the effectiveness of systemic herbicides for control of nutsedge and also to assess 
the effect of chemical weed control on growth and yield of subsequent field 
crops. 
In Ex. no. I, allelopathic influence of purple nutsedge on 
important field crops like rice, ragi, cowpea, green gram, bitter gourd and bhindi 
were studied. The treatments comprised of aqueous extracts and blended 
extracts of fresh and dry plant parts of nutsedge. The results revealed that 
aqueous extracts of nutsedge inhibited germination of rice, ragi, bitter gourd and 
bhindi while it had some stimulatory effect on germination of cowpea and green 
gram. The early growth characters of the field crops were found suppressed by 
the aqueous extract treatment while the blended extract showed no effect. In 
general, the dry plant parts showed greater effect than the fresh material. 
Under Ex.no.Il, field studies were made to investigate the 
effectiveness of systemic herbicides viz. Glyphosate and 2,4-D for control of 
nutsedge. The treatments included different doses of the herbicides with and 
 
without adjuvants and Glyphosate combined with sublethal dose of 2,4-D. The 
results revealed that lowest dose of the herbicides were sufficient for complete 
kill of the purple nutsedge plants in the experimental area and there was no 
regrowth upto 6 weeks. There was significant reduction in viability of tubers 
collected one month after herbicide application, but the tubers tested 45 days 
after spraying showed an increase in germinability over the record on 30th day. 
Tubers from treatments involving Glyphosate with sublethal dose of 2,4-D 
recorded the lowest sprouting percentage indicating the possibility for weed 
control for a longer period. 
In Ex. no. In, the persistence of the herbicides in soil were 
monitored and it was observed that early growth of cucumber sown on the same 
day of herbicide application was affected while that sown on soils collected 10 
days after spraying recorded growth characters comparable to that of control. 
From Ex.no.IV, it could be inferred that chemical weed control 
did not show any deleterious effect on growth and yield characteristics of ragi 
and cucumber sown 15 days after the treatments. Application of 2,4-D for 
nutsedge control was found superior to other treatments in terms of net income 
and B:C ratio and the lower unit cost of the chemical was precisely the reason 
for its superiority. 


UR  - https://krishikosh.egranth.ac.in/handle/1/5810156279
ER  -