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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY-SOUND PEST, WATER AND SOIL MANAGEMENT STRATEGIES FOR NORTHERN GREAT PLAINS CROPPING SYSTEMS

Location: Agricultural Systems Research Unit

Title: Tillage, crop rotation, and cultural practice effects on dryland soil carbon fractions

Authors
item Sainju, Upendra
item Lenssen, Andrew
item Caesar, Thecan
item Jabro, Jalal "jay"
item Lartey, Robert
item Evans, Robert
item Allen, Brett

Submitted to: Open Journal of Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 2012
Publication Date: October 10, 2012
Repository URL: http://handle.nal.usda.gov/10113/57707
Citation: Sainju, U.M., Lenssen, A.W., Caesar, T., Jabro, J.D., Lartey, R.T., Evans, R.G., Allen, B.L. 2012. Tillage, crop rotation, and cultural practice effects on dryland soil carbon fractions. Open Journal of Soil Science. 2(3):242-255.

Interpretive Summary: In the northern Great Plains, traditional farming systems, such as conventional tillage with spring wheat-fallow system, for the last 50 to 100 yr have decreased soil C storage by 30 to 50%. Both tillage and fallowing reduce soil organic C by increasing soil organic matter mineralization and reducing the amount of plant residue returned to the soil. As a result, traditional farming systems have become unsustainable and uneconomical. Therefore, information is needed on novel management practices to increase dryland C sequestration and soil quality in the northern Great Plains. We evaluated the effects of tillage, crop rotation, and cultural practice on dryland crop biomass (stems and leaves) yield, surface residue, and soil C fractions at the 0- to 20-cm depth in a Williams loam from 2004 to 2008 in eastern Montana. Treatments were two tillage (no-tillage [NT] and conventional tillage [CT]), two crop rotations (continuous spring wheat [CW] and spring wheat-barley hay-corn-pea [W-B-C-P]), and two cultural practices (regular [conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height] and ecological [variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height]). Carbon fractions were soil organic C (SOC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Crop biomass was 24 to 39% greater in W-B-C-P than in CW in 2004 and 2005. Surface residue C was 36% greater in NT than in CT in the regular practice. At 5 to 20 cm, SOC was 14% greater in NT with W-B-C-P and the regular practice than in CT with CW and the ecological practice. In 2007, POC and PCM at 0 to 20 cm were 23 to 54% greater in NT with CW or the regular practice than in CT with CW or the ecological practice. Similarly, MBC at 10 to 20 cm was 70% greater with the regular than with the ecological practice in NT with CW. Surface residue and soil C fractions declined from autumn 2007 to spring 2008. No-tillage with the regular cultural practice increased surface residue and soil C storage and microbial biomass and activity compared with conventional tillage with the ecological practice. Without crop residue input, surface residue and soil C fractions declined from autumn to spring due to mineralization.

Technical Abstract: Information is needed on novel management practices to increase dryland C sequestration and soil quality in the northern Great Plains. We evaluated the effects of tillage, crop rotation, and cultural practice on dryland crop biomass (stems and leaves) yield, surface residue, and soil C fractions at the 0- to 20-cm depth in a Williams loam from 2004 to 2008 in eastern Montana. Treatments were two tillage (no-tillage [NT] and conventional tillage [CT]), two crop rotations (continuous spring wheat [Triticum aestivum L.] [CW] and spring wheat-barley [Hordeum vulgaris L.] hay-corn [Zea mays L.]-pea [Pisum sativum L.] [W-B-C-P]), and two cultural practices (regular [conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height] and ecological [variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height]). Carbon fractions were soil organic C (SOC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Crop biomass was 24 to 39% greater in W-B-C-P than in CW in 2004 and 2005. Surface residue C was 36% greater in NT than in CT in the regular practice. At 5 to 20 cm, SOC was 14% greater in NT with W-B-C-P and the regular practice than in CT with CW and the ecological practice. In 2007, POC and PCM at 0 to 20 cm were 23 to 54% greater in NT with CW or the regular practice than in CT with CW or the ecological practice. Similarly, MBC at 10 to 20 cm was 70% greater with the regular than with the ecological practice in NT with CW. Surface residue and soil C fractions declined from autumn 2007 to spring 2008. No-tillage with the regular cultural practice increased surface residue and soil C storage and microbial biomass and activity compared with conventional tillage with the ecological practice. Without crop residue input, surface residue and soil C fractions declined from autumn to spring due to mineralization.

Last Modified: 9/21/2014
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