MSc

Lab and field experiments were conducted at the Instructional
Farm, College of Agriculture, Vellayani during June 2001 to February
2002 to study the allelopathic influence of eupatorium (Chromolaena
odorata (L.) King and Robinson) on important field crops and weed
species and to investigate the potential of the weed biomass as organic
manure.
In Experiment I, allelopathic influence of eupatorium on three
important field crops ie., rice (Oryza sativa L.), cowpea (Vigna
unguiculata (L.) Walp.) and Bittergourd (Momordica charantia L.) and
two weed species. ie ., Thatch grass (lmperata cylindrica (L.) Beauv.)
and eupatorium (Chromofaena odorata (L.) King and Robinson) was
studied. The treatments comprised of aqueous plant part leachates of
fresh and decayed eupatorium at five and ten per cent co ncentr at io n.
The results revealed that aqueous fresh plant part leachates inhibited
germination and early seedling growth of rice, cowpea and bittergourd
severely. Germination of thatch grass and eupatorium were also
suppressed by the treatments. In general, the aqueous fresh plant part
leachates showed greater effect than the decayed plant part leachates,
and the effect was more -with leaf leachate. The inhibitory effect was
more with the higher concentration of the leachate.
Under Experiment II, field observations were made to study the
biology of eupatorium under Kerala conditions. Composting of mature
eupatorium was tried and the response of bhindi to eupatorium as
compost and green leaf manure was observed in comparison with poultry
manure, vermicompost, coirpith compost and farmyard manure.
The results revealed that eupatorium took about 293 days from
germination to seed maturity under Kerala conditions. The plant
flowering was during December - January and seeds dispersed in the

months of February - March. Each plant produced about 25,000 seeds
on an average and had a germination percentage of about 30 per cent.
When the mature and dried eupatorium weed biomass was
composted, the C : N ratio came down from 62.72 to 18.88 in four
months and was ready for use as organic manure. The NPK content of
the composted material was 0.76, 0.58 and 0.81 per cent respectively.
The yield response of bhindi to eupatorium as organic manure
revealed that eupatorium compost was on par with poultry manure and
farmyard manure treatments. However when the fresh weed biomass
was used as green leaf manure, the yield was considerably lower. The
results indicated the need and usefulness of composting the weed
biomass before using it as sole source of organic manure in bhindi.