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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #142849
Title: AGRONOMIC AND ECONOMIC IMPLICATIONS OF CONSERVATION TILLAGE AND ULTRA-NARROW ROW CROPPING SYSTEMS

Author
item HARMAN, W - TEXAS A&M UNIVERSITY
item GERIK, T - TEXAS A&M UNIVERSITY
item Torbert, Henry - Allen
item Potter, Kenneth

Submitted to: National Conservation Tillage Cotton and Rice Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/23/2003
Publication Date: 1/23/2003
Citation: Harman, W.L., Gerik, T., Torbert III, H.A., Potter, K.N. 2003. Agronomic and economic implications of conservation tillage and ultra-narrow row cropping systems. National Conservation Tillage Cotton and Rice Conference Proceedings.Jan. 23-24, Houston, TX. p. 11-13.

Interpretive Summary: Crop production in the southern Great Plains is most common limited by soil water supply. Profitability and economic risk are directly related to productivity and therefore linked to water availability. Managing water resources to maximize production requires advanced planning, capital, and a willingness to change by the producer. Since evaporation losses represent a large portion of the total water lost, minimizing evaporation by reducing tillage, or switching to ultra-narrow rows, could conserve sufficient water to increase yield. Field studies were conducted to examine the implications of ultra narrow rows and conservation tillage systems on corn and grain sorghum production. Yields increased 56 pounds/ac for corn and 60 pounds/ac for sorghum, for each inch reduction in row spacing from 40- to 20-inch rows. No-till systems produced yields equal to conventional tillage in wet years and greater in dry years (adding to no tillage system income). The costs of no tillage systems are reduced when small tractors with chemical application equipment replace large tractors and heavy tillage equipment. The acreage of corn needed to breakeven for the cost of converting to a conservation tillage system was 29 to 87 acres, depending on the system used. Breakeven acreage decline as expected seasonal rainfall drops below average and increase when it exceeds the average.

Technical Abstract: Water deficits are the biggest yield limitation of dryland crops in Texas and the southern Great Plains. Managing this resource to maximize production requires advanced planning, capital, and a willingness to change by the producer. Since evaporation losses represent a large portion of the total water lost, minimizing evaporation by reducing tillage, or switching to ultra-narrow rows (UNR), say 20 inches or less, could conserve sufficient water to increase yield. Field studies were conducted to examine the implications of UNR and conservation tillage (CsT) on corn and grain sorghum production. Results were dramatic over a wide range of weather conditions. For corn and sorghum, yields increased 56 and 60 lbs/ac, respectively, per inch reduction in row spacing from 40- to 20-inch rows. No-till (NT) systems produced yields equal to conventional tillage (CT) in wet years and greater in dry years. Higher yields during dry years add to NT income. NT costs are reduced when small tractors with chemical application equipment replace large tractors and heavy tillage equipment. Based on average seasonal rainfall and when net present value of returns over 10-years equal investment costs, the breakeven corn acreage required to convert from a 40-inch CT system to a 40-inch NT system is 29 acres; to a 20-inch NT system, 87 acres; and to a 20-inch CT system, 82 acres. Breakeven acreage decline as expected seasonal rainfall drops below average and increase when it exceeds the average.