Antagonistis responses to crop diversification at two levels of fertiliser and herbicide application

The use of pesticides and fertilisers in the last decades has led to numerous problems for
mankind and the environment: polluted ground water, decreased soil quality, biodiversity
loss and resistance of weed and pest species. To counteract these problems, conventional
farming systems will need to become more sustainable. One approach is intercropping,
which is common in traditional or low intensity farming, but not in conventional agriculture.
Thus, little is known about responses of biotic interactions to intercropping under
conventional management. In a cereal-legume intercropping experiment, we found that
disease infection was highest in cereal sole crops and weed biomass was highest in legume
sole crops, while herbivory was highest in intercrops. Management intensity had significant
effects on pathogen infection, herbivory and weed biomass, but results differed between
wheat-bean vs barley-pea cropping systems, showing that intercropping in conventional
agriculture can reduce antagonistic patterns, but also that plant species must be specifically
chosen for optimised performance with respect to reduced external inputs.