Emergence, survival and seed production of Enteropogon ramosus in a pasture-wheat rotation or continuous pasture rotation in the wheatbelt of Western Australia.

摘要

Enteropogon ramosus is a native, perennial, C₄ grass species found within the wheatbelt of Western Australia. Emergence, survival, seed production and seed dormancy of E. ramosus was investigated in a continuous pasture rotation, a pasture-minimum tillage wheat rotation, and a pasture-minimum tillage wheat rotation where a cultivation event at the beginning of the pasture year was used to kill all E. ramosus plants. The results indicated that E. ramosus could germinate throughout the year, although plant density (ranging annually from 0 to 17 plants m-2) was lowest in conditions of low rainfall (summer-autumn drought). Seed production (estimated from seed head production, r=91.7, P<0.001) ranged from 0 to 2274 m-2 and was greatest in spring, in the continuous pasture rotation. Seed germinability reached 80-89%, following an initial 3 months of dormancy directly after seed production. Cultivation at the beginning of the pasture-crop rotation killed all plants, reduced emergence and prevented seed production for the 2-year period of the experiment. Soil disturbance from minimum tillage crop sowing reduced but did not eliminate E. ramosus plants. As a result, E. ramosus grew throughout the year in the minimum tillage cropping system. Further research is required to determine the competitive effect of E. ramosus on crop growth.