Abstract: To study the plant parameters of intercropped crops, the temporal variation of plant height, plant cover, and leaf area index in intercropped area of Sichuan was investigated in 2005. The results showed that the plant height, plant cover, and leaf area index all varied greatly with time. For corn, its maximum plant height was 177 cm, maximum plant cover was 86% occurring at flowering stage, and maximum leaf area index was 1.96. For sweet potato, its maximum and minimum plant height was 22 cm and 12 cm, respectively, maximum plant cover was 73% occurring at tuber expanding stage, and maximum leaf area index was 1.79. When intercropped with corn, all the test plant parameters of sweet potato were strongly affected by corn. In this intercropping system, the most dangerous erosion period was from the corn being harvested to the sweet potato growing up where soil surface uncovered by harvesting corn.

Key words: Maize aphids, Niche breadth, Niche overlap, Rhopalosiphum maidis Fitch