摘要：Positive interactions in plant communities.Positive interactions(or facilitation):the presence of oneplant enhances the growth，survival，or reproduction of aneighbor(+/+，+/0，+/-)(Callaway&Walker,1997).maximum biomass or cumulative nutrient (N,P,K) uptake of intercropped species≥monocultures.temporal niche differentiation:(1)differences in plant sowing date,(2)interspecific competition, and (3) presence/absence of management practices such as film mulching.temporal dynamics in nutrient uptake rates between neighboring plants could significantly contribute to improving the productivity of species-diverse assemblages.
