Workpackage 4: Intercropping for weed, pest and disease management

The main objectives of this Workpackage are: 

•  Evaluate the effect of intercropping on weed competition and pests and diseases.

• Determine intercropping strategies for limiting weed competition.

• Identify how root competition for nutrients could explain weed limitation in intercrops.

In order to meet these objectives, the Workpackage is divided in five sub-packages, each of them involving different partners as well as requiring different methodology:  

·         Workpackage 4.1 (Partners 4, 1, 3, 5, 7): Comparison of weed infestation and pests and disease pressure between intercrop, sole crop and fallow will be performed in the basic pea-barley experiment shared by all partners (described in WP 2). Weed species frequency determination, weed biomass and N content at flowering stage of the legume and at harvest will be performed. Monitoring of pests and diseases will be conducted at key phenology stages. Soil borne-diseases will be monitored in succeeding crops.

·         Workpackage 4.2 (Partners 4, 1): Partner 4 will use white mustard and rye grass as weeds models. Measurements include dry matter production, nutrient accumulation by crop and weeds, N₂ fixation estimates by ¹⁵N, soil N analysis, and leaf area and canopy light distribution. Partner 1 will work on fababean-spring wheat ICs and study two levels of population density, intercrop frequency two soil fertility levels. The weed and crop biomass will be measured at two harvests and at maturity. Crop grain yield will also be determined.

·         Workpackage 4.3 (Partner 4): Competition for nutrients, especially soil inorganic N and P, is expected to be a major mechanism for weed suppression by intercropping. A greeen-house study on root competition for nutrients will be conducted during two years. In Year 1 a study of root elongation rate of pea, barley, white mustard and rye grass will be conducted in a rhizotron. In Year 2 a Pea-barley/white mustard or rye grass system will be used as study model. The experiment will be carried out in greenhouse with soil tubes separated or not in two compartments, which allow or deny the crops-weeds system for root competition. Aerial dry matter (leaf, stems, reproductive), %N, %P, ¹⁵N and root biomass per 10 cm of soil will be recorded.

     Professor Yves Crozat (y.crozat@esa-angers.educagri.fr) from Ecole Supérieure d'Agriculture (Angers) is the  partner responsible for this Workpackage.