Plants create a carbon/humus sponge that is the most superior method of retaining water thus fuelling soil biology and nutrient cycling, plant growth and vine health.
The photos below show how well ground cover works after rain.
This photo shows a section of soil with no cover. 5 hours after a rain period the soil surface was dry. Beneath the surface the soil was almost completely dry. Most of the moisture simply evaporated before it could penetrate the surface. No plant matter on or in the soil creates compacted soils.
Soil under vine with remanent plant & root residues protecting the surface. This photo is taken between drippers 5 hours after rain. Notice the colour difference that moisture makes.
Same as above but under vine at dripper outlet. Notice the moisture holding just below surface. The plant residues are creating the sponge affect so water hangs around for longer with less evaporation to atmosphere.
Vineyard mid row bare surface section (a meter apart). This is 5 hours after rain. Notice how dry the surface is. Most of the rain has evaporated before being able to infiltrate.
Vineyard mid row, next to bare surface area that has surface plant residue pulled back to expose moist soil surface, 5 hours after rain. Notice the colour difference to photo above.