The research on
interaction effect and physio-ecological mechanisms in plants has the positive instruction on the recovery
and reconstruction of vegetation and improvement of productivity in the agri-forestry ecosystem. Based on the analysis of the
interaction effect among different plants, it has been emphasized to summarize the influence of plant interaction on nutrient availability in plant and soil as well as plant biomass in agri-forestry system. And the main conclusions have been as follows: (1) The plant interaction could accelerate the growth of roots and strengthen the nutrient competition among plant roots. (2) The
allelopathy effect among plants exists universally in natural and cultivated ecosystem, which should be well utilized in plant farming. (3) The interaction contributes to the nutrient transfer in the body of plant and improves the nutrient status, so it achieves the nutrient complementary between two plants. (4) The interaction could enhance soil fertility effectively, improve nutrient status in soil and nutrient absorption in the rhizosphere, and also maintain plant productivity. (5) The interaction would be favorable for plants to use available resources such as light, heat, water, soil as well as nutrient and alleviate damages from the pests as possible, which is beneficial to increase crop yield. In both the mutual cultivated plants, leguminous plant due to its ability of nitrogen fixation can provide enough nitrogen nutrients for its partner. Therefore, the mutual complementary of nitrogen and reduction of volatilization and eluviation in nitrogen would contribute to the high crop yield. Generally, this positive effect attributed to interaction effect would become more evident under the condition of nitrogen deficiency.