Effect of Different Weed Management Strategies on Population Changing Pattern of Pennisetum polystachion in Coconut Plantations of Sri Lanka

  • S. H. S. Senarathne
  • Shashi Shermila Udumann
Keywords: Seedling emergence, Tiller emergence, Cover crops, Harrowing, Ploughing

Abstract

Pennisetum polystachion is a major problematic monocotyledonous weed species and a perennial problem in intermediate zone of coconut plantations in Sri Lanka. This study was carried out to evaluate the impacts of different management systems on P. polystachion seedling emergence patterns. The tested treatments were application of glyphosate (T1), cover cropping with Pueraria phaseoloides (T2), tractor harrowing (T3), tractor slashing (T4) and tractor ploughing (T5). All the treatments were applied twice a year except T2. As T2 cover crop at the initiation of the experiment and over grown conditions were managed by harrowing once a year. Based on the reduction in weed biomass, cover cropping (T2) was the best to reduce the P. polystachion population and to reduce P. polystachion seedling emergence density in the field. Chemical weeding was the second-best method to control the P. polystachion population in the field. The effectiveness of slashing in reducing weed seedling emergence density was lower than cover cropping and chemical weeding methods. The weed seedling emergence densities were almost similar in ploughed and harrowed plots. The seed depth of emerged seedling was very high in harrowed and ploughed treatments when compared to other treatments. Results given by T3 and T5 indicates that loosening the soil creates more favorable environment for the germination of weed seeds buried in soil. Therefore, it can be argued that the elimination of weed seeds in the top 2 cm or 4 cm in the soil seed bank by any means is likely to reduce the level of weed infestation by about 60% to 95%. Results also indicated that burying rhizomes in ploughing and harrowing treatment plots at the depths below 30 - 40 cm is effective in controlling germination of this weed species. This experiment also suggested that keeping rhizomes on the soil surface without burying for durations of 5 – 15 days would produce weak plants with poor development.

Author Biography

S. H. S. Senarathne

Agronomy Division, Coconut Research Institute, Lunuwila, Sri Lanka

References

Ball, D.A., 1992:Weed Seed Bank Response to Tillage, Herbicides and Crop Rotation Sequence.Weed Science 40, 654-659.
Coffin, D.P., and W.K. Lavenorth, 1989:Spatial and Temporal Variations in the Seed Bank of a Semiarid Grassland, American J. Botany, 76, 53-58.
Csurhes S and Edwards R, (1998). Potential Environmental weeds in Australia. Candidate species for preventative control, Environment Australia, Canberra, Australia.
De Alwis, K.A. and C.R Panabokke, 1972:Hand Book of the Soils of Sri Lanka (Ceylon). Journal of Soil Science Society, Ceylon, 2, 1-97.
Hodgkinson, K.C., Harrington, G.N., and G.E. Miles, 1980:Composition Spatial and Temporal Variation of the Soil Seed Pool in a Eucalyptus Populens Shrub Woodland in Central New South Wales, AustralianJ. Ecolology, 5, 23-29.
Holt JS, Orcutt DR. 1996. Temperature thresholds for bud sprouting in perennial weeds and seed germination in cotton. Weed Science, 44,523–533.
King, L.S., 1966: Weeds of the World, Biology and Control, Leonard Hill Books, London and New York, 526.
Liyanage, L.V.K., and M.S.de Liyanage, 1989: Weed Control Under-story Weed Management in Coconut Lands.CORD, 1, 48-56.
Mapa, R.B., Dasanayake, A.R. and H.B. Nayakekorale, 2005:Soils of the Intermediate Zone of Sri Lanka, Special Publication, Soil Science Society of Sri Lanka, 70-95.
Parsons, W. T./Cuthbertson, E. G. 1992. Noxious weeds of Australia. Inkata Press, Melbourne/Sydney. 692 pp.
Pethiyagoda, U. 1980: Handbook on Coconut Cultivation. Ceylon Printers Limited, Colombo: 68–70.

Punyawardena, B.V.R., Bandara, T.M.J., Munasinghe, M.A.K. and Bandara, N. J. (2003). Agro ecological regions of Sri Lanka. Natural Resource Management Centre, Department of Agriculture, Peradeniya, Sri Lanka.

Rice, K.J., 1989:Impacts of Soil Seed Bank on Grassland Community Structure and Population Dynamics.In Ecology of Soil Seed Banks (ed by Leck M.A., Parker, V.T. and Simpson, R.L.) Academic Press, San Diego, 211-230.
Robert, H.A., 1968:The Changing Population of Viable Weeds Seeds in Arable Soil, Weed Research, 8, 253-256.
Roberts, H.A. and P.M. Feast, 1973:Change in the Numbers of Viable Weed Seeds in Soil Under Different Regimes, Weed Research 13, 112-116.
[SAS] Statistical Analysis Systems, 1999:SAS 1, STAT Users Guide, Release, 7.00 Cary, NC: Statistical Analysis Systems Institute, 1028.
Senarathne S.H.S., Samarajeewa, A.D. and K.C.P. Pererea, 2003:Comparison of Different Weed Management Systems and their Effects on Yield of Coconut Plantations in Sri Lanka. Weed Biology and Management. 3, 158-162.
Senarathne, S.H.S. and Sangakkara, U.R.. (2010).Influence of moisture, pH, depth of burial and submerged conditions on seed germination and seedling emergence of major weed species in coconut plantaions of Sri Lanka, Korean Journal of Weed Science, 30 (3): 206-214
Smith, NM (1995). Weeds of Natural Ecosystems. A field guide to environmental weeds of the Northern Territory, Australia, Environment Centre, Darwin, Northern Territory.
Simpson, R.L., Leck, M.K.,and Y.T. Parker, 1989:Seed Banks:General Concepts and Methodological Issues.In: LECK, M.A., PARKER, V.T., SIMPSON, R.L.Ecology of soil seed banks.London: Academic Press, ppg. 3-8.
Swanton, C.J. and S.F. Weise, 1991:Integrated Weed Management:The Rational and Approach, Weed Technology, 5, 657-663.
Thill, D.C., Lish, J.M., Callihan, R.H. and E.J. Bechinski, 1991:Integrated Weed Management - A Component of Integrated Pest Management:A Critical Review.Weed Technology, 5: 648-656.
Witharama, W.R.G. 1998:Studies on Weed Populations in Sugarcane in Sri Lanka.PhD, thesis, Aberdeen, Scotland; University of Aberdeen, 212.
Published
2019-04-01
How to Cite
Senarathne, S. H. S., & Udumann, S. S. (2019). Effect of Different Weed Management Strategies on Population Changing Pattern of Pennisetum polystachion in Coconut Plantations of Sri Lanka. CORD, 35(1), 43-50. https://doi.org/10.37833/cord.v35i01.12
Section
Articles