Submitted to: Southern Conservation Tillage for Sustainable Agriculture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/24/2002
Publication Date: 6/24/2002
Citation: Raper, R.L., Sharma, A.K. 2002. Using soil moisture to determine when to subsoil. 25TH Annual Southern Conservation Tillage for Sustainable Agriculture Proceedings. June 24-26, 2002. Interpretive Summary: Breaking up compacted soil layers using tillage is necessary for many U.S. soils. However, the energy costs can be substantial. Also, tillage could result in excessive surface soil disruption that could unnecessarily expose bare soil to rainfall. This experiment was conducted to determine the energy requirements and the soil disturbance caused by two subsoilers, a straight shank and a "minimum-tillage" shank at four moisture contents in a Coastal Plains soil. The results show that increased energy requirements and increased soil disturbance results from subsoiling at extremely dry conditions. A "minimum-tillage" shank required more energy than the straight shank but also caused more soil disturbance on the soil surface. Producers wishing to subsoil to disrupt compacted soil layers should not operate at either extreme of soil moisture. Subsoiling in extremely wet soil conditions may lead to additional compaction due to vehicle traffic. Subsoiling in extremely dry soil conditions may increase energy requirements and surface disruption.
Technical Abstract: An experiment was conducted to determine the optimum moisture content to subsoil based on tillage forces and on soil disruption. Two different shanks, a straight shank and a "minimum-tillage" shank, were tested in a Coastal Plains soil in the soil bins of the National Soil Dynamics Laboratory in Auburn, AL. A three-dimensional dynamometer was used to measure tillage forces, and a laser profilometer was used to measure soil disruption. Tillage forces and soil disruption from the driest moisture content were found to be greater than results from all other moisture contents tested. The "minimum-tillage" shank was found to require more energy and disrupt the soil a lesser amount than the straight shank.