| Intercropping is defined as “a kind of multiple cropping system with two or more crops grown simultaneously in alternate rows in the same area.” Intercropping is traditional and widespread China where on nearly ¼ of the total arable land intercropping is practiced. Two major intercropping systems are common: strip intercropping and relay intercropping. In addition, there are field border effects and unconscious intercropping, meaning due to land scarcity and limited field size farmers try to maximize crop production in time and space. Intercropping is known as a good working system in low input systems, then often overyielding its monoculture equivalent, and considered as a balance between competition and facilitation concerning resource use efficiency and nutrient uptake: whether there is competition for solar radiation and soil water content or an improved nutrient uptake because of synergistic effects. As there are multiple possibilities for intercropping designs, it is very time consuming and expensive to investigate in field trials. Thus, modeling approaches could be a useful tool to simulate plant growth and behavior under different environmental circumstances in order to advise appropriate cropping strategies. The most common modeling approach for interspecific competition is to extend a sole crop model with a competition-submodel. Similarly, a usually crop-weed or a multispecies ecosystem model can be extended to model a crop-crop performance. The other approach is to draw near the competitive effects more theoretical with mathematical and dimensional assumptions. In most cases, the models have similar basic assumptions when considering competition for solar radiation. The aim of this study was to gain an overview over intercropping practice in China. First results indicate that there is a great potential for those systems, but in a sense there are gaps in knowledge about interspecific effects in the field and a need for perfecting existing patterns. Some models showed that it is possible to simulate intercropping with some respect and to use these models to study interspecific competition more closely. Nevertheless, these model studies are mostly case studies not par for par conferrable to Chinese cropping and environmental conditions. |
