Optical contact angle of air-dry soil samples at maize BBCH50

The optical contact angle of the samples was measured by attaching a one-grain layer of the air-dry soil sample to a piece of tape and releasing a drop of water onto it. The contact angle was determined from the image of the water drop on the soil (see supplementary pictures). The soil samples were taken from unrooted bulk soil and maize rhizosphere 18 weeks after the cover crops had been terminated with a herbicide. At this time, maize was growing on the site, and had reached BBCH stage 50. Research domain: Soil Sciences Research question: How hydrophobic is the soil in the rhizosphere of maize.