Dynamics of buried seed population and seedling cohorts of two dominant weeds in a hill agroecosystem of the humid subtropics of India
Tóm tắt
Dynamics of the buried seeds and plant population of two dominant weeds, viz.,Emilia sonchifolia (Linn.) DC. andRichardsonia pilosa HBK were studied in the crop fields of Meghalaya, north-east India during radish and maize cropping and intervening fallow periods. The total buried seed population ofR. pilosa was always larger than that ofE. sonchifolia, but the germinable fraction was invariably greater in the latter. A major portion (39–41%) of the viable (germinable+dormant) seed population in both weeds was confined to the surface soil layer (0–5 cm). The viable seed population ofE. sonchifolia peaked during April, while that ofR. pilosa showed two peaks (during August and December). The survival pattern and half-lives of seedling cohorts showed, some differences in the two weed species, but both being summer annuals, their populations behaved in a similar manner by showing higher seedling recruitment (K) and survivorship (p) rates in the summer crop (maize) than in the winter crop (radish). However, the density of plants that could attain adulthood was significantly higher inE. sonchifolia thanR. pilosa which might have resulted in greater seed input of the former to the soil leading to its greater abundance in the crop fields.
Tài liệu tham khảo
Antonovics, J. and D. A. Levin (1980) The ecological and genetic consequences of density dependent regulation in plants.Annu. Rev. Ecol. Syst. 11: 411–452.
Barallis, G. (1965). Aspects ecologiques des mauvaises herbes dans les cultures annuelles.C.r. 3ème Conf. Columa, Paris.
Baskin, J. M. and C. C. Baskin (1978) The seed bank in a population of an endemic plant species and its ecological significance.Biol. Conserv 14: 125–130.
Baskin, J. M. and C. C. Baskin (1990) The role of light and alternating temperatures ongermination ofPolygonum aviculare, seeds exhumed on various dates.Weed Res. 30: 397–402.
Cook, R. E. (1980). Germination and size-dependent mortality inViola blanda.Oecologia 47: 115–117.
Deevey, E. S. (1947) Life tables for natural populations of animals.Q. Rev. Biol. 22: 283–314.
Eddleman, L. E. and J. T. Romo (1988) Spotted knapweed germination response to stratification, temperature and water stress.Can. J. Bot. 66: 653–657.
Egley, G. H. (1990) High-temperature effects on germination and survival of weed seeds in soil.Weed. Sci. 38: 429–435.
Fernandez-Quintanilla, C. L. Navarrette, J. L. G. Andujar, A. Fernandez and M. J. Sanchez (1986) Seeding recruitment and agespecific survivorship and reproduction in populations ofAvena sterilis ssp.ludoviciana.J. Appl. Ecol. 23: 945–955.
Fernandez-Quintanilla, C., L. Navarrette, C. Torner and J. L. Anjuar (1987) Influence of herbicide treatments on the population dynamics ofAvena sterilis ssp.ludoviciana (Durieu) Nyman in winter wheat crops.Weed Res. 27: 375–383.
Firbank, L. G., R. Cousen, A. M. Mortimer and R. G. R. Smith (1990) Effects of soil type on crop yield-weed density relationships between winter wheat andBromus sterilis.J. Appl. Ecol. 27: 308–318.
Hayashi, I., J. V. Pancho and S. S. Sastroutomo (1978) Preliminary report on the buried seeds of floating islands and bottom of Lake Rawa Pening, Central Java.Jap. J. Ecol. 28: 325–333.
Kropac, Z., (1966) Estimation of weed seeds in arable soil.Pedobiologia 6: 105–128.
Mack, R. N. (1976) Survivorship ofCerastium atrovirens at Aberffraw, Anglesey.J. Ecol. 64: 309–312.
Mack, R. N. and D. A. Pyke (1983) The demography ofBromus tectorum: Variation in time and space.J. Ecol. 71: 69–93.
Malone, C. R. (1967) A rapid method for enumeration of viable seeds in soil.Weeds 15: 381–382.
Misra, J., H. N. Pandey, R. S. Tripathi and U. K. Sahoo (1992) Weed population dynamics under ‘jhum’ (slash and burn agriculture) and terrace cultivation in northeast India.Agric. Ecosyst. Environ. 41: 285–295.
Misra, R., (1968)Ecology work book. pp. 32–33. Oxford and IBH, New Delhi.
Mortimer, A. M., D. J. McMahon, R. J. Manlove and P. D. Putwain (1980) The prediction of weed infestations and cost of differing control strategies.Proceedings 1980 British weed Control Conference-Weeds. pp. 415–422.
Moss, S. R. (1988) Influence of cultivations on the vertical distribution of weed seeds in the soil.VIII th International Symposium on the Biology, Ecology and Systematics of Weeds, pp. 71–80, 14–16 September, Dijon.
Pandey, H. N. and S. K. Dubey (1989) Growth and population dynamics of an exotic weedParthenium hysterophorus L.,Proc. Indian Acad. Sci. (Plant Sci.) 99: 51–58.
Rai, J. P. N. and R. S. Tripathi (1984) Population dynamics of different seedling cohorts of two co-existing annual weeds,Galinsoga ciliata andG. parviflora on two contrasting sites.Acta Oecol. Oecol. Plant. 5: 357–368.
Rauber, R. (1978) Möglichkeiten der Erarbeitung von Modellen zur Befallsprognose bei Unkräutern, dargelegt am Beispiel von Flughafer (Avena fatua L.) in Getreide. Dissertation, Hohenheim.
Roberts, H. A. and M. E. Rickets (1979) Quantitative relationship between the weed flora after cultivation and the seed, population in the soil.Weed Res. 19: 269–275.
Sahoo, U. K., R. S. Tripathi, H. N. Pandey and J. Misra (1994) Population dynamics of buried weed seeds as, influenced by shifting and terrace cultivation in the humid subtropics of Indian.Weed Res. 34: 157–165.
Tayalla, O. E., A. G. T. Babiker, M. G. Mansi and N. H. M. Beshir (1988) Influence of glumes, soil and environmental conditions on germination ofIschaemum afrum (J. F. Gmel). Dandy seeds.Weed Res. 28: 237–241.
Wilson B. J. and G. W. Cussans (1975) A study of the population dynamics ofAvena fatua L. as influenced by straw burning, seed shedding and cultivations.Weed Res. 15: 249–258.
Yadav, A. S., and R. S. Tripathi (1981) Population dynamics of the ruderal weedEupatorium odoratum and its natural regulation.Oikos 36: 355–361.