Asparagus (Asparagus officinalis L.) root tissue added to soil at 2, 4, or 6g (dry weight basis) per 100 g of dry soil generally inhibited lettuce and delayed tomato and asparagus seedling emergence when incorporated in soil for 0 or 28 days before seeding. The toxicity of the 2 and 4 g rates of asparagus root tissue was diminished after 50 days, but the 6 g rate inhibited and/or delayed emergence 50 and 90 days after incorporation in soil. These results suggest that asparagus root tissues contain a hetero- and auto-toxic allelopathic compound(s) that is inactivated with increasing time in the soil.
Received for publication 5 Nov. 1984. Paper of the J. Ser. of the New Jersey Agr. Expt. Sta. No. D-12104-30-83. This work is taken in part from a thesis submitted by W. Shafer to Rutgers Univ. in partial fulfillment of the requirements for the MS degree. Supported by State and U.S. Hatch Act Funds. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.
Former Graduate Research Assistant. Present Address: Dept. of Horticulture, Michigan State Univ., East Lansing, MI 48824.