Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Other
Publication Acceptance Date: March 1, 2005
Publication Date: July 19, 2005
Citation: Qiu, H., Williams, J.D., Wu, J., Flerchinger, G.N., Oviatt, H.S., Wuest, S.B., Mccool, D.K. 2005. Effects of tillage and residue management on seed-zone temperature and moisture: field investigation and shaw modeling. American Society of Agri Engineers Special Meetings and Conferences Papers.
The high soil loss rate in Pacific Northwest (PNW) has long been recognized as a serious environmental problem. Winter precipitation combined with steep land slopes and frequent soil freezing-thawing cycle, often result in winter runoff and erosion. Agricultural practices in the dryland farming area often leave bare soil unprotected during fallow periods and after fall seeding. No-till farming has been recommended as an agricultural best management practice for dryland farming in the PNW. In general, no-till systems increase water infiltration and retain more water in the seed-zone for crop use, reduce surface runoff and erosion, and improve soil quality. No-till residue management practices may also reduce evaporation. The objective of this study was to use the Simultaneous Heat and Water (SHAW) model to simulate the effects of land management practices on soil temperature and moisture and to evaluate the hydrologic implications of these practices. Two residue management scenarios were evaluated and compared: no-till (NT) typifying heavy residue, and residue incorporation (RI) representing lighter residue.
Field data and model results both show that surface residue has evident effects on seed-zone soil temperature and moisture. Heavy residue under NT acts as an insulation layer, resulting in less soil temperature fluctuation and potentially fewer freezing-thawing cycles than found in fields with incorporated residue. Under the NT treatment, the heavy residue presents greater resistance to evaporative loss which effectively improves general soil moisture conditions in the seed-zone for germination and retains more water available for use by the crop.