Abstract: The use of extension engineering theory to evaluate allelopathic potential of exudates from cultured cucumber (Cucumis sativus L. ) roots provides a novel approach for the quantitative assessment of allelopathy between crops and scientific guidance for modern agriculture industry. A combination of cultured root techniques and extension engineering methods was used to theoretically assess the allelopathic potential of cultured cucumber root exudates on four test crops: bean ( Phaseolus vulgaris L. ) , cucumber, melon (Cucumis melo L) , and tomato (Lycopersicon esculentum L. ). Extension measurement of allelopathic potential of cultured cucumber root exudates indicated that cucumber significantly stimulated the growth of bean seedlings. In contrast, cultured cucumber root exudates significantly inhibited cucumber, melon, and tomato seedlings. A mathematicalmodel, R_E = [ k₁R_p0 / ( k₂ - k₁ ) ] ( e^{- k1 t} - e^{- k2 t} ) ( e^{- k1a} - e^{- k2a} ) , was developed to show the dependence of allelopathic potential (RE ) of cultured cucumber root exudates on culture time ( t) and root exudate concentration ( a) where R_p0 = R_E when t = 0. Significant differences in the chemical interference of cucumber root exudates on seedling growth of the four acceptor crops demonstrates inter- or intra-specific relationships related to the plant accession causing allelochemical reactions. Extension evaluation of allelopathic potential of the exudates from cultured cucumber roots theoretically shows that beans are an app rop riate choice for intercropping with cucumbers or as a successive crop after cucumber harvest.

Key words: Cucumber, Exudates of cucumber cultured roots, Assessment of allelopathic potential, Extension Engineering principle, Mathematical modeling