How to Increase Infiltration in Clay

Test the infiltration rate of your clay soil to determine the course of a soil management plan. The infiltration rate is how fast the soil absorbs water. Dig a hole about 8 inches wide and deep with a shovel. Stick a ruler in the hole. Fill the hole with water and time how long it takes to infiltrate water into the soil. An infiltration rate slower than 1 inch per hour indicates soil requiring extra management.

Increase the size and depth of clay soil's pores, or openings between particles to speed up infiltration and decrease runoff and puddling. Disk the topsoil to reduce areas of hardpan layers. Break up the surface crust and clods with a chisel plow or disk. Run a rotary hoe over the field to punch holes in hard-packed clay. Truck in loads of sand or loam to form stable soil aggregates with the clay.

Add organic-rich dirt such as muck or compost to a clay soil garden. Spread organic matter such as manure or humus over clay fields to improve the soil's texture and encourage soil biota such as earthworms and ants. Improve the structure of clay soil by the addition of plant material. Apply whatever is locally available, corn or soybean debris, rice husks or grass clippings. Till it in deeply during spring plowing.

Plant and maintain vegetation on the clay soil to increase aeration and water infiltration from the biomass. Grow a "green manure" cover crop rich in nitrogen to protect the soil from raindrop impact compaction. Plow the plants under in the fall to increase the soil's tilth, or workability. Rotate crops such as legumes and long-rooted grasses for better soil porosity and more stable soil aggregates. Plant species with large root systems for increased soil permeability.

Reduce soil compaction from heavy farm and tillage equipment. Avoid compressing the clay soil and its infiltration pores by going over the fields only when absolutely necessary. Manage the size of grazing cattle or sheep herds on clay soil pastures and meadows to avoid damaging the soil's structure by compaction. Break up compacted hardpan with deep tillage of more than 10 inches. Vary the tillage depth over the years to avoid the formation of compacted tillage pans just below the level of cultivation.