Computer Modelling of Crop Alignments Could Fight Weeds in an Environmentally Way

Light interception is closely related to canopy architecture. Few studies based on multi-view photography have been conducted in a field environment, particularly studies that link 3D plant architecture with a radiation model to quantify the dynamic canopy light interception. In this study, Binglin Zhu and colleagues combined realistic 3D plant architecture with a radiation model to quantify and evaluate the effect of differences in planting patterns and row orientations on canopy light interception.

The three-dimensional architecture of maize and soybean plants were reconstructed for sole crops and intercrops based on multi-view images obtained at five growth dates in the field. The authors evaluated the accuracy of the calculated leaf length, maximum leaf width, plant height and leaf area according to the measured data. The light distribution within the 3D plant canopy was calculated with a 3D radiation model. Finally, the team evaluated canopy light interception in different row orientations.

“In this study, we obtained canopy point clouds with high accuracy for crops grown in the field,” write Zhu and colleagues. “At the early growth stages, it required approximately 15 min to capture 80-120 multiview images for each treatment and approximately 3.5 hours to reconstruct the 3D architecture of the targeted canopy. To guarantee the accuracy of the canopy architecture under serious occlusion at 62 d after emergence, it required approximately 30 min to capture 160-200 multi-view images for each treatment and approximately five hours to reconstruct the canopy architecture. Ten seconds were required for each radiation simulation of each canopy. Therefore, there was still a substantial advantage compared with that of manual measurements…”

There was good agreement between the measured and calculated phenotypic traits. The light distribution was more uniform for intercropped maize and more concentrated for sole maize. At the maize silking stage, 85% of radiation was intercepted by approximately 55% of the upper canopy region for maize and by approximately 33% of the upper canopy region for soybean. There was no significant difference in daily light interception between the different row orientations for the entire intercropping and sole systems. However, for intercropped maize, near east-west orientations showed approximately 19% higher daily light interception than near south-north orientations. For intercropped soybean, daily light interception showed the opposite trend. It was approximately 49% higher for near south-north orientations than for near east-west orientations.

“We can quantify the shading effect of crops on the weed canopy zone and explain the shading inhibition of weed growth with the method proposed in this paper. This will enable us to better understand the competition for light in a field environment and to alter the row orientation of crops to suppress weeds in an environmentally friendly way.”