Abstract: The karst terrain in Guangxi is widespread, and the problem of rocky desertification has seriously affected the local economic development. The development of a reasonable compound planting model in karst areas can bring significant economic benefits and also have a positive effect on the management of rocky desertification. Soybean is a common cash crop in the karst area of Guangxi, and the introduction and promotion of Zanthoxylum bungeanum has also become one of the poverty alleviation industries in the karst area. In the early growth stage of Z. bungeanum, three soybean interplanting densities were set between rows, and their effects on the growth characteristics, leaf water content, and photosynthetic capacity of Z. bungeanum were analyzed. The results showed that the treatment with high intercropping density （45 soybeans/㎡） had higher water content in the leaves of Z. bungeanum and better plant growth; interplanting Z. bungeanum can not only obtain short-term benefits of soybeans, but also enhance the photosynthesis of Z. bungeanum and promote the growth of Z. bungeanum.

Key words: Karst, Zanthoxylum bungeanum, soybean, interplanting, photosynthesis