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Aspects of the Population Dynamics of the Weed Alopecurus myosuroides Huds. in Winter Cereal Crops
Robert E. L. Naylor
Journal of Applied Ecology
Vol. 9, No. 1 (Apr., 1972), pp. 127-139
Published by: British Ecological Society
Stable URL: http://www.jstor.org/stable/2402051
Page Count: 13
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Field observations permit a quantification of factors involved in the population dynamics of the winter annual weed Alopecurus myosuroides (blackgrass). Experimental simulation of the theoretical effects of ploughing, both to different depths, and at dinerent times of the year, indicates the optimum method of cultivation for control of blackgrass populations, and reduction of its seed populations in the soil. A technique involving the marking of seed with fluorescent paint, and the recovery of seedlings with seed attached was used to determine the contribution of young seed to future populations. It was shown that about two-thirds of a population of blackgrass is derived from seed less than 1 year old. This proportion would be a lot lower if the mouldboard plough was efficient at burying seeds by totally inverting the soil profile. Plants of A. myosuroides are remarkably plastic, reproductive output varying by at least as much as forty times. Nevertheless some seed is usually set by all mature plants. It is shown the spikelets of A. myosuroides may not contain a ripe caryopsis; the proportion without varies between localities and times of harvest. Caryopsis weight is normally distributed around the mean. Some aspects of the dormancy of blackgrass are summarized.
Journal of Applied Ecology © 1972 British Ecological Society