Weed control with alfalfa pellets in transplanting rice

Alfalfa [ Medicago sativa L. ( M. media , M. falcate )] plants contain allelochemicals that have detrimental effects on their own growth and that of surrounding plants. Alfalfa pellets, used as a food for livestock, were used as the material for the control of weeds in this study. In a greenhouse experiment, alfalfa pellets applied at 1–3 tons ha⁻¹ completely inhibited the emergence of abunome ( Doparium junceum Hamilt.), false pimpernel ( Lindernia pyxidaria L.), and long stemmed water wort ( Elatine trianda Schk. var. pedicellata Krylov) The number and the dry weight of emerged Echinochloa oryzicola plants were significantly reduced. Application of 3 tons ha⁻¹ alfalfa pellets completely inhibited the emergences of Eleocharis acicularis and Rotala indica. Results demonstrated that the inhibitory effect of alfalfa pellets became greater as the dose increased, and it also varied among weed species. Furthermore, the paddy field experiment suggested that the dose of 1–2 tons ha⁻¹ of alfalfa pellets could control more weed species without any rice plant injury.