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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Publications at this Location » Publication #395433

Research Project: Sustainable Small Farm and Organic Grass and Forage Production Systems for Livestock and Agroforestry

Location: Dale Bumpers Small Farms Research Center

Title: Spatial and temporal variability of soil organic carbon on a corn-soybean watershed with 23 years of agroforestry

item SALCEDA, MIGUEL - University Of Missouri
item UDAWATTA, RANJITH - University Of Missouri
item NELSON, KELLY - University Of Missouri
item MENDIS, SIDATH - University Of Missouri
item BARDHAN, SOUGATA - University Of Missouri

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2021
Publication Date: 12/16/2021
Citation: Salceda, M., Udawatta, R.P., Nelson, K.A., Mendis, S.S., Bardhan, S. 2021. Spatial and temporal variability of soil organic carbon on a corn-soybean watershed with 23 years of agroforestry. Agronomy Journal. 114(1):440-451.

Interpretive Summary: The average decadal growth of carbon dioxide was 2 parts per million (ppm) in the 2000s and surged to 2.4 ppm a year during 2010-2019 period. This long-term paired watershed study at the MU’s Greenley Research Center evaluated the role of agroforestry on soil organic carbon (SOC) storage. The study results showed that integration of agroforestry on corn-soybean watersheds increased SOC in the perennial vegetative areas. The greatest increase in SOC between 2000 and 2020 was found in the agroforestry soils.

Technical Abstract: Unsustainable agricultural practices deplete soil organic carbon (SOC), affecting ecosystem services, land productivity, soil health, and water quality. This study evaluated the long-term effects of row crop (RC), agroforestry buffers (AB), grass buffers (GB), and grassed waterways (GWW) on SOC. Agroforestry buffers (grass and tree) and grass buffer treatments were established in 1997 on a corn (Zea Mays L.)–soybean (Glycine Max [L]. Merr.) rotation. Grid soil samples from 86 locations were collected in 10 transects to determine SOC at 0–10 and 10–20 cm depths. The general linear model and the generalized linear mixed model were conducted to evaluate treatment, landscape, soil depth, and series effects on SOC. Kriging interpolation was used to visualize the temporal and spatial change of SOC in the watersheds, comparing samples collected in 2000 and 1994 with samples collected in 2020. The mean SOC percentage (SOC%) in the top 10 cm depth for the RC, AB, GB, and GWW areas was 1.94, 2.19, 2.41, and 2.51%, respectively (' < .001). The soil depth was significant (' < .001) between samples from 0–10 cm and 10–20 cm. The mean SOC% among soil series showed no significant differences at the studied depths. The mean SOC% of 0–10 cm for RC, AB, and GWW were 1.85, 1.88, and 2.30% in 2000 and 1.94, 2.19, and 2.51% in 2020. The foot-slope position had the highest (2.41%) and the summit position had the lowest SOC (2.02%) percentages. The SOC% in the RC treatment from 0–10 cm at the summit, backslope, and foot slope positions were ranked 1.83 < 2.22 < 2.31%, respectively. Perennial vegetation and undisturbed land management practices increased SOC compared with the RC areas.