Selection of ideal succeeding crops after asparagus, taro and beans replanting field in seedling growth bioassay

摘要

Sixty seven cultivars of 42 vegetable crop species from 14 families were tested in seedling growth bioassay using the used nutrient solution of Asparagus officinalis L. and replanting of Asparagus officinalis L., Colocasia esculenla Schott., Vicia faba L., Pisum sativum L. and Phaseolus vulgaris L. to select possible succeeding crops. Replanting problems due to continuous cropping is typically a chemical interference from previous crops or their residues in the soil and autotoxicity has been often suggested as one of the possible reasons. Growth performances of succeeding crops were assayed using once used nutrient solution and/or replanting soil of these crops. Bioassay using asparagus used nutrient solution with or without activated charcoal (AC)suggest the tested cultivar of cucumber, garden pea, komatsuna, melon, pak-choi cv. Tyoukou', parsley, soybean (except cv. 'Tankurou'), cabbage cv. 'Early Ball' and lettuce cv. 'Shato' as succeeding crops. Bioassay using replanting soil with or without Activated Charcoal suggested that most of the cultivars tested can be planted after asparagus, taro, and three beans (Vicia faba L., Pisum sativum L. and Phaseolus vulgaris L.) with little adverse effects. Among the three methods of bioassay used (i). Nutrient solution, (ii). Direct seed sowing and (iii). Seedling transplanting in replant soil; the nutrient solution bioassay proved more sensitive than replanting soil bioassay. However, results of nutrient solution bioassay may not be reproducible in thefield condition. Therefore, seedling transplanting method can be used as an easy and practical bioassay method to select succeeding crops for fields with replanting problems.