Diversity Increases Yield but Reduces Reproductive Effort in Crop Mixtures

By Jianguo Chen and Nadine Engbersen et.al

Resource allocation to reproduction is a critical trait for plant fitness. This trait, called harvest index in the agricultural context, determines how plant biomass is converted to seed yield and consequently financial revenue of numerous major staple crops. While plant diversity has been demonstrated to increase plant biomass, plant diversity effects on seed yield of crops are ambiguous. This discrepancy could be explained through changes in the proportion of resources invested into reproduction in response to changes in plant diversity, namely through changes of species interactions and microenvironmental conditions. Here we show that increasing crop plant diversity from monoculture over 2- to 4-species mixtures increased annual primary productivity, resulting in overall higher plant biomass and, to a lesser extent, higher seed yield in mixtures compared with monocultures.