Abstract: The biochemical interaction between various groups of organisms is called allelopathy.It is acommon phenomenon between higher plants,higher-lower plants,insects-plants,higher animals,and phyto-and zooplankton.It is revealed by experimental investigations that certain chemicalsubstances,particularly alkaloids,flavonoids and terpenoids,play an important role in suchbiochemical interaction between or ganisms.It was suggested that research on allelopathy shouldbe carried out as early as possible in order to accelerate the development of ecological bioche-mistry,a new branch of ecological sciences in our country.

Key words: maize-soybean relay strip intercropping, reduction of N application, yield, nutrient uptake, N utilization efficiency.