This patchy appearance is common when water moves through soil and carries the mobile nutrients with it. Water does not move down through the soil in a united wetting front. It tends to move laterally until it finds the least resistance soil to move through. The movement produced is called preferential flow.
Preferential flow carries nutrients to deep depths with relatively small amounts of water.
A number of studies using tracers to mark water movement have shown preferential flow to be the common method of downward water movement in soils. Because the water moves to deep depths in certain areas, these are the areas that leach out nutrients and form the patches of deficiency we see at the surface. With smaller amounts of rainfall, nutrients from areas not experiencing deep water movement may spread out and decrease the variability in smaller areas, however, some variability will exist for some time. Another consequence of the heavy rains will be the expansion and appearance of saline seeps later this season and continuing into next year. Around ponds, a ring of salt will develop and retard or inhibit crop growth.