Spatial variation of grain yields in a field-scale pea-barley intercrop

Crop yield and quality can vary substantially within agricultural fields. Precision farming techniques is one approach to adapt to this spatial challenge by employing site-specific management of field heterogeneity to enhance local crop productivity within the field (Mulla,2013). Another approach is intercropping strategies based on the ecological principles of competition, facilitation and complementarity suggested as an ‘ecological precision farming’ technique where the crop itself will adjust its botanical composition in response to spatially variable resources such as plant-available nitrogen (Jensen et al., 2015).In spring 2020, on a sandy loam soil located 20 km west of Copenhagen, Denmark (558400N, 128180E), we grew a 4.5-hectare field with pea (cv. Ingrid) and barley (cv. KWS Irina) in dual 50%:50% replacement intercrop design as compared to the recommended plant density when sole cropped (100%). In that way the total relative plant density is kept constant when comparing to control strips of sole cropped barley and pea. The experiment was placed along a gradient of known differences in soil texture, bulk density and organic matter content. A plot combine harvester were used to get a spatial impression of the within
field heterogeneity by individually harvesting 15 m2 every 10 m in selected strips across the field. Based on a comprehensive data analysis we discuss how to increase the spatial stability in grain yield and quality of the intercrop components, demonstrating intercropping as a promising and straightforward low-tech approach to reduce the negative impact of field heterogeneity.