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United States Department of Agriculture

Agricultural Research Service

Title: Carbon Sequestration in Dryland Soils and Plant Residue As Influenced by Tillage and Crop Rotation

Authors
item Sainju, Upendra
item Lenssen, Andrew
item Caesar, Thecan
item Waddell, Jed

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 29, 2004
Publication Date: July 16, 2006
Repository URL: http://hdl.handle.net/10113/3818
Citation: Sainju, U.M., Lenssen, A.W., Caesar, T., Waddell, J.T. 2006. Carbon sequestration in dryland soils and plant residue as influenced by tillage and crop rotation. Journal of Environmental Quality. 35:1341-1347.

Interpretive Summary: Drylands in northern Great Plains have lost 30 to 50% of their original soil organic C (SOC) levels during the last 50 to 100 yr due to continuous cultivation and summer fallowing. While cultivation is done to prepare seed beds for planting crops and controlling weeds, fallowing is done to increase soil water storage and production of succeeding crops. Intensive tillage increases the oxidation of SOC and fallowing increases its loss by reducing the amount of plant residue returned to the soil. Increased soil moisture and temperature during fallowing can also accelerate mineralization of SOC. Soil is vulnerable to wind erosion during fallow, which further increases its loss. A 6-yr experiment from 1998 to 2003 consisting of two tillage practices [conventional till (CT) and no-till (NT)], five crop rotations [continuous spring wheat (CW), spring wheat-fallow (W-F), spring wheat-lentil (Lens culinaris Medic.) (W-L), spring wheat-spring wheat-fallow (W-W-F), and spring wheat-pea (Pisum sativum L.)-fallow (W-P-F)], and Conservation Reserve Program (CRP) planting was conducted in Havre , MT to determine their effects on plant C input, SOC, and particulate organic C (POC). Total plant biomass returned to the soil from 1998 to 2003 was greater in CW (15.5 Mg ha-1) than in other rotations. Residue cover, amount, and C content in 2003 were 33 to 86% greater in NT than in CT and greater in CRP than in crop rotations. Residue amount (2.47 Mg ha-1) and C content (0.96 Mg ha-1) were greater in NT with CW than in other treatments, except in CT with CRP and W-F and in NT with CRP and W-W-F. The SOC at 0- to 5-cm was 23% greater in NT (6.4 Mg ha-1) than in CT. The POC was not influenced by tillage and crop rotation, but POC/SOC ratio at 0- to 20-cm was greater in NT with W-L (369 g kg-1 SOC) than in CT with CW, W-F, and W-L. From 1998 to 2003, SOC at 0- to 20-cm decreased by 4% in CT but increased by 3% in NT. Carbon can be sequestered in dryland soils and plant residue in areas previously under CRP using reduced tillage and increased cropping intensity, such as NT with CW, compared with traditional practice, such as CT with W-F system, and the content can be similar to that in CRP planting.

Technical Abstract: Long-term use of conventional tillage and wheat (Triticum aestivum L.)-fallow systems in the Northern Great Plains have resulted in low soil organic C (SOC) levels. We examined the effects of two tillage practices [conventional till (CT) and no-till (NT)], five crop rotations [continuous spring wheat (CW), spring wheat-fallow (W-F), spring wheat-lentil (Lens culinaris Medic.) (W-L), spring wheat-spring wheat-fallow (W-W-F), and spring wheat-pea (Pisum sativum L.)-fallow (W-P-F)], and Conservation Reserve Program (CRP) planting on plant C input, SOC, and particulate organic C (POC). A field experiment was conducted in a mixture of Scobey clay loam (fine-loamy, mixed, Aridic Argiborolls) and Kevin clay loam (fine, montmorillonitic, Aridic Argiborolls) from 1998 to 2003 in Havre, MT. Total plant biomass returned to the soil from 1998 to 2003 was greater in CW (15.5 Mg ha-1) than in other rotations. Residue cover, amount, and C content in 2003 were 33 to 86% greater in NT than in CT and greater in CRP than in crop rotations. Residue amount (2.47 Mg ha-1) and C content (0.96 Mg ha-1) were greater in NT with CW than in other treatments, except in CT with CRP and W-F and in NT with CRP and W-W-F. The SOC at 0- to 5-cm was 23% greater in NT (6.4 Mg ha-1) than in CT. The POC was not influenced by tillage and crop rotation, but POC/SOC ratio at 0- to 20-cm was greater in NT with W-L (369 g kg-1 SOC) than in CT with CW, W-F, and W-L. From 1998 to 2003, SOC at 0- to 20-cm decreased by 4% in CT but increased by 3% in NT. Carbon can be sequestered in dryland soils and plant residue in areas previously under CRP using reduced tillage and increased cropping intensity, such as NT with CW, compared with traditional practice, such as CT with W-F system, and the content can be similar to that in CRP planting.

Last Modified: 12/19/2014
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