EFFECTS OF CELERY (APIUM-GRAVEOLENS) ROOT RESIDUE ON GROWTH OF VARIOUS CROPS AND WEEDS

The relative sensitivity of various crops and weeds to celery root res idue incorporated into soil was determined in greenhouse experiments. A range of concentrations was used to determine the percentage of cele ry residue needed to cause a 50% reduction in plant growth (I50). The most sensitive weed was spiny amaranth and the least sensitive was com mon purslane. The most sensitive crop was radish and the least sensiti ve was celery. Selectivity was calculated as crop I50/weed I50 and var ied from a maximum of 13 for celery and spiny amaranth to a low of 0.4 for radish and common purslane. Selective weed suppression might be o btained when celery residue is present. Nomenclature: Celery, Apium gr aveolens L.; radish, Raphanus sativus L.; common purslane, Portulaca o leracea L. #3 POROL; spiny amaranth, Amaranthus spinosus L.# AMASP.