ABSTRACT
The development and maintenance of water-stable aggregates at the soil surface is, perhaps, the best indication of physical condition improvements. Through both scientific scrutiny and on-farm application, it has been noted that significant, sustainable increases in organic matter content are achievable only in an extended absence of tillage with significant levels of residues maintained on the soil surface. Adequate surface cover is necessary before a given soil can reach its best quality. Average runoff from conventional and long-term no-till was 16.2 and 1.8%, respectively, while runoff losses from low-return-frequency storms were 52.6 and 21.8%. While research measurements have documented increases in bulk density under long-term no-till, air and water movements seem to remain adequate or even improve. One of the more significant improvements through long-term no-till is the increase in the cation exchange capacity of the soil. Perhaps one of the more complete studies showing the relationship between long-term no-till and soil biology was made by C. L. Crovetto.
