ARS | Publication request: Improving Water Quality and Conserving Soil Using Soil Amendments.

Submitted to: Proceedings Brazilian Soil Science Society
Publication Type: Proceedings/Symposium
Publication Acceptance Date: June 1, 2007
Publication Date: August 5, 2007
Citation: Norton, L.D. 2007. Improving Water Quality and Conserving Soil Using Soil Amendments. In: Proceedings XXXI Congress Brazilian Soil Science Society, August 5-10, 2007, Gramado, Rio Grande do Sul, Brazil. 2007 CDROM.

Technical Abstract: Conservation tillage such a no-tillage has widely been shown to control soil erosion compared to other forms of management that involved some extent of tillage. However, in no-tillage most if not all the chemicals are placed near or on the soil surface which makes their movement more likely to occur when runoff is produced. This can have adverse effects on downstream water quality especially with respect to agricultural pesticides and nutrients. Many soil amendments have been shown to be effective at stabilizing soil aggregates and improving infiltration by mixing them in cultivated soils. This can not be done in no-tillage without destroying the soil erosion benefits obtained, especially by long-term no-till management. The objective of this paper is to summarize ten years of soil amendment research results on various tillage management systems, and especially no-tillage, on improving water quality and controlling soil erosion. Results indicate that in both cultivated and no-tillage systems soil amendments that release electrolytes to rain water can reduce soluble phosphorus concentrations significantly when applied to the soil surface. Gypsum whether mined, recycled dry wall, or synthetic gypsum from flue gas desulphurization (FGD) have proved to be useful soil amendments in a wide range of soils by reducing runoff volume and improving steady state infiltration rates. Gypsum when surface applied along with other materials such as anionic polyacrylamide (PAM) was even more effective at improving infiltration rates and reducing soil erosion. However, both gypsum and anionic polyacrylamide have difficulties for surface application that farmers do not like. FGD gypsum is a very fine powder which when broadcast has considerable problems with blowing in wind. PAM when dissolved in water becomes very viscous and requires large amounts of water to be applied as a spray which becomes non-practical for farmers. A new material where pelletized FGD gypsum granules serve as a carrier for dry PAM application will be discussed for conserving soil and water.