Winter wheat and summer shade

Abstract:

Agroforestry research is in full expansion, but uncertainty remains on the performance of combinations of species with regard to the broad range of possible species associations. In addition, the variability of environmental conditions under which agroforestry stands can be successfully developed is unknown. Under Belgian pedoclimatic conditions, tree-crop competition for light might be the principal limiting factor in the agroforestry context. Most studies show that shade stress induces a systematic reduction of final crop yield. However, the response of a specific crop to shade is highly dependent on environmental conditions. In agroforestry systems, the tree canopy reduces the incident radiation for the crop following a dynamic spatio-temporal pattern. In this study, we will report on the efficiency of wheat under artificial dynamic shade in the experimental farm of Gembloux Agro-Bio Tech, Belgium in order to evaluate it’s potential for agroforestry purposes in the same region. Wheat productivity and development under artificial shade conditions have been monitored during 1 year and the observations will be continued for 2 more years. We constructed an artificial shade structure, which mimics the light environment observed under hybrid walnut agroforestry trees: periodic fluctuation in radiation transmittance and discontinuous light quantity. We collected information on biomass development, soil state and radiation patterns in the field. Using this data, we evaluated the influence of dynamic shade, light availability and the efficiency with which energy is converted in wheat dry matter under the artificial shade treatment. This, in combination with modeling, will allow a thorough study of the potential of wheat-walnut agroforestry systems in the Hesbaye region in Belgium.