How does water move horizontally in soil?
In normal conditions with rain or surface watering, studies show that roots absorb around 70% of their water from the top half part of the root depth and 30% from the lower half. Wetness patterns differ based on the soil type. In sandy soil, water moves more vertical and less horizontal. In clay or loam soil, water also moves vertical but less rapidly, allowing time for the water to also more horizontally. Subsurface watering gets water deeper into the root growth area. As soaking occurs with RWS, water will make its way horizontally into the surrounding soil, more so in clay and loam soils than sandy soils.