The soil aeration and organic material mixing previously done by the earthworms has ceased in some areas.

Neem Cake improves the organic matter content of the soil, helping improve soil texture, water holding capacity, and soil aeration for better root development.

The improvements were attributed to the higher legume nodulation in the presence of AMF, better water infiltration, and soil aeration due to soil aggregation.

The thinning action is highly beneficial in itself as it provides soil aeration at depth without disturbing adjacent roots systems.

Instead of mounding mulch deeper, which could interfere with soil aeration, spread the layer of mulch out wider.

"I think that soil aeration is more important for home lawns than fertilizing," said Jeff Ball, an author of "Yardening" (Macmillan Publishing, $24.95).

Buckingham's first work on soil physics is on soil aeration, particularly the loss of carbon dioxide from the soil and its subsequent replacement by oxygen.

Earthworms also stimulate microbial activity by increasing soil aeration and moisture, and transporting litter into the ground where it becomes available to other soil fauna.

By so doing it allows easier penetration of water into the soil, increases soil aeration and enhances the activity of soil biota.

Soluble polyacrylamide polymers are used to flocculate the irrigated soil thus improving water penetration and soil aeration while diminuishing soil erosion.