Part 1, Section 1: Soil Management
Soil Health
Improving Soil Health
Soil Profile Modification
The soil profile is customarily modified by tillage (Figure 1.1-3). Tillage mixes soil and crop residues in the surface, pulverizes aggregates, increases soil sealing and crusting at the very surface of the soil, compacts soil just below the tillage tool, and leads to a decline in certain earthworm species (nightcrawlers especially) that make deep burrows into the subsoil. In long-term no-till, on the other hand, the soil profile is characterized by mulch cover that protects the soil from the elements and provides a food source and habitat for soil organisms, high organic matter content near the surface that decreases rather abrubtly with depth, macro-pores (many created by nightcrawlers) that lead from the surface 3–4 feet into the soil, and a firm soil that has intact aggregates. The changed soil profile in long-term no-till leads to higher infiltration and reduced evaporation, and also makes the soil better trafficable. It should be noted that the soil profile modification needs time to develop but can be changed rapidly by one tillage pass. Hence the importance of long-term no-tillage.
