Long-term integration of bahiagrass into a cover-cropped and strip-tilled peanut-cotton rotation has a limited effect on soil carbon and fertility

Authors: MALTAIS-LANDRY, GABRIEL - University Of Florida; JAMES, MICHEAL - University Of Florida; WILSON, CHRIS - University Of Florida; Schumacher, Lesley; GRABAU, ZANE - University Of Florida; SIDHU, SUDEEP - University Of Florida; GEORGE, SHEEJA - University Of Florida

Submitted to: Soil Science Society of America Journal
Publication Type: Research Notes
Publication Acceptance Date: 10/3/2023
Publication Date: 10/12/2023
Citation: Maltais-Landry, G., James, M., Wilson, C., Schumacher, L.A., Grabau, Z., Sidhu, S., George, S. 2023. Long-term integration of bahiagrass into a cover-cropped and strip-tilled peanut-cotton rotation has a limited effect on soil carbon and fertility. Soil Science Society of America Journal. https://doi.org/10.1002/saj2.20602.
DOI: https://doi.org/10.1002/saj2.20602

Interpretive Summary: Long-term integration of bahiagrass into a cover-cropped and strip-tilled peanut-cotton rotation has a limited effect on soil carbon and fertility. Cotton and peanut are commonly grown crops in the southeastern United States. To avoid pests and pathogens, farmers rotate these crops. While there are many crop rotation systems to choose from, sod or grass-based rotation remains a common choice. Yet, little is known about the long-term effects of this rotation on soil properties. Therefore, we evaluated the effects of irrigation, crop rotation (sod-based and conventional), and depth on soil carbon and extractable nutrients after 18 years of long-term research. In the top 30 cm of soil, soil carbon was 6% higher in the sod-based rotation than the conventional rotation. However, at deeper depths (from 30-120 cm), there were no discernible differences between the two rotation systems. There was no effect of sod-based rotation on other soil properties, except for potassium, which was lower in the sod-based rotation due to reduced fertilizer inputs. This work helps growers evaluate how their farming practices affect soil properties to understand if fertilizer inputs can be reduced and crop yield goals achieved.

Technical Abstract: Integrating a perennial grass like bahiagrass (Paspalum notatum Flugge) in the traditional rotation of cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) increases yields and reduces irrigation needs in the Southeast US. However, the long-term effects of this sod-based rotation (SBR) on soil properties remains unclear. Eighteen years after establishing SBR and the traditional rotation, we collected samples to a depth of 1.2 m in 30 cm increments and measured soil carbon and other soil properties (e.g., Mehlich-extractable nutrients). Soil C was 6% higher with SBR in the top 30 cm of soil after 18 years, with no impact on soil C in deeper soil layers. Similarly, there was no effect of SBR on other soil properties, except for lower soil K due to smaller fertilizer K inputs in SBR. Our results indicate a limited effect of SBR on soil C and other properties in this system where SBR is not grazed and where strip tillage and cover cropping were implemented in both rotations.