Hybrid and Irrigation Effects on Conservation Tillage Corn in the Coastal Plain
1985
Karlen, D. L. | Sojka, R. E.
Conservation tillage (CT) can reduce soil erosion loss, but to be voluntarily implemented, corn (Zea mays L.) yield must not be reduced when compared with conventional tillage practices such as disking periodically (DP). We compared CT and DP treatments with and without irrigation on Norfolk (fine-loamy, siliceous, thermic Typic Paleudults) sandy loam for 4 yr to determine if hybrid selection, water management, or soil temperature caused CT corn yields to be lower than where DP was used for seedbed preparation. Plant emergence and early season growth were consistently more rapid and uniform with DP than with CT. Water was conserved in CT treatments, but this increased grain yield only under nonirrigated conditions in 1981. Average daily soil temperature for 14 days after planting was 19 °C for both tillage systems and 22 or 24 °C for CT and DP treatments for days 15 to 28. When averaged for 28 days after planting, soil temperatures in CT treatments were 0.5 °C less at 0800 h and 1.1 °C less at 1500 h. Those soil temperature differences do not appear to be sufficient to cause slower, nonuniform emergence, growth, and generally lower corn grain yield when CT practices are used in this region, although maximum yield potential for corn appears to be physiologically initiated very early during the growing season. Therefore, a successful conservation tillage system must promote rapid, uniform germination, and emergence of all plants.
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