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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #427856
Research Project: Dryland and Irrigated Crop Management Under Limited Water Availability and Drought

Location: Soil and Water Management Research

Title: Long-term cover crop management effects on soil properties in dryland cropping systems

Author
item SIMON, LOGAN - Kansas State University
item OBOUR, AUGUSTINE - Kansas State University
item HOLMAN, JONATHAN - Kansas State University
item ROOZEBOOM, KRAIG - Kansas State University

Submitted to: Agriculture, Ecosystems & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2022
Publication Date: 1/10/2022
Citation: Simon, L.M., Obour, A.K., Holman, J.D., Roozeboom, K.L. 2022. Long-term cover crop management effects on soil properties in dryland cropping systems. Agriculture, Ecosystems & Environment. 328. Article 107852. https://doi.org/10.1016/j.agee.2022.107852.
DOI: https://doi.org/10.1016/j.agee.2022.107852

Interpretive Summary: Cover crops lead to mixed outcomes in High Plains dryland agriculture. Adoption of cover crops in cropping systems is purported to increase crop water productivity and allow cropping intensification in semi-arid environments like western Kansas and the Texas and Oklahoma Panhandles. But, cover crops use water that may not then be available to the follow-on cash crop. Kansas State University scientist working in an ARS Ogallala Aquifer Program project investigated the effectiveness of cover crops to increase soil carbon and improve soil aggregation, which is important for rainfall infiltration. They found that simple cover crop mixtures or monocultures had similar soil properties as a diverse mixture. Cover crops had greater soil aggregation compared to fallow or peas for grain. Cover crops had similar effects on soil properties when hayed or left standing. Soil organic carbon was greater with cover crops in 2012 but not different than fallow in 2018.

Technical Abstract: Replacing summer-fallow by growing cover crops (CC) in semi-arid regions might provide several soil health benefits. This study examined the effects of long-term CC management in place of fallow on soil properties in a no-till (NT) winter wheat (Triticum aestivum L.)-grain sorghum (Sorghum bicolor Moench)-fallow (WSF) cropping system. Fallow replacement treatments were spring-planted and included peas (Pisum sativum L.) for grain as well as one-, three-, and six-species CC mixtures compared with summer-fallow. Half of each CC treatment was harvested for forage and the other half remained standing after termination. Soil organic carbon (SOC) stocks within the 0- to 15-cm soil depth increased by 0.14 Mg ha**-1 yr**-1 for each Mg ha**-1 CC residue added from 2008 to 2012 and were unaffected by CC diversity. However, SOC stocks were not different than fallow in 2018 likely because CC residue inputs declined due to a succession of drought years. Residue contribution from grain sorghum in the WSF rotation best predicted SOC in 2018 compared to 2012. Soil aggregation was greater with CCs compared to peas or fallow and was unaffected by CC diversity. Mean weight diameter (MWD) of water stable aggregates in 2018 was greater with standing CCs (1.11 mm) compared to peas (0.77 mm) but was similar to fallow (0.84 mm). The MWD of dry aggregates with standing (3.55 mm) and hayed (3.62 mm) CCs were greater compared to fallow (2.75 mm). Our findings suggest simple CC mixtures and CCs managed for hay provide similar soil benefits as diverse CC mixtures or CCs left standing in this semi-arid environment.