Submitted to: Strategies for No Till
Publication Type: Popular Publication
Publication Acceptance Date: January 15, 1996
Publication Date: N/A
Technical Abstract: Rainfall patterns within the growing season of the Cornbelt are characterized by periods of unevenly distributed rainfall. Increasing water conservation in the early part of the growing season could enhance crop production by supplying available water to the crop during critical growth stages later in the season. Since crop growth has been related to the total amount of transpiration, the more water available, the greater the potential growth. Observations in evapotranspiration have been made in no-till, chisel-plow, and ridge-tillage fields since 1991 in the Walnut Creek watershed south of Ames, Iowa. These measurements are made in farmer-operated fields that range in size from 35 to 50 ha. A Bowen ratio setup is placed near the center of the field to provide 30-minute totals of evapotranspiration. No-till and ridge-tillage fields have the lowest soil water evaporation rate in the spring because of the reduced amount of tillage. These totals vary from 25 to 50 mm and result in an increased soil water storage in the root zone. Evapotranspiration rates were greater in the no-till fields followed by ridge-tillage and then chisel-plow as the soils began to dry. The increase in stored soil water was able to maintain the evapotranspiration rate at a maximum for 4 to 6 days longer in the no-till fields. The increase in water availability increases the chance of receiving significant rainfall. In the Cornbelt, water management through the use of no-till practices can reduce the risk in crop production due to water stress at critical times during the growing season.