Studies of Ephedra plants in Asia. Part 3: The weed control problem in Ephedra cultivated field in China

Managing weeds is critical for successful Ephedra cultivation. Thus we investigated weed control of 4 Ephedra fields in the provinces of Nei-meng-gu and Ning-xia in China. Weeds that collected in the Ephedra fields were taxonomically classified into 63 taxa of 49 genera of 16 families. The major ones were the plants in 4 families: Chenopodiaceae, Compositae, Gramineae and Leguminosae. Of the weeds, Sonchus brachyotus, Artemisia spp., Calamagrostis spp. and some Chenopodiaceae plants caused serious damage to cultivated Ephedra plants. Sonchus brachyotus branched out densely over Ephedra plants, and Calamagrostis spp. grew much taller than Ephedra plants and made thick colonies. As a result, these weeds over shadowed the Ephedra plants and took away nutrients from them, and the growth of Ephedra plants was seriously inhibited. Furthermore, these weeds were difficult to pull out entirely by hand, because they had scissile long underground rhizomes. For effective weed control in Ephedra fields, it is necessary to pull out S. brachyotus and Calamagrostis spp. during the early stage of growth, when their rhizomes are immature. Although the plants of Chenopodiaceae and Artemisia spp. that have no long rhizomes also grew taller than Ephedra plants, they could be easily pulled out. In addition, Chloris virgata and Eragrostis minor were smaller than Ephedra plants, and it was difficult to pull out them manually when they grew among the tufted stems of Ephedra plants. Harvested together with Ephedra plants, the two species are likely to lower the quality of production of the crude drug "Mahaung".