Adoption of a biologically-enhanced agricultural management (BEAM) approach in agroecosystems for regenerating soil fertility, improving farm profitability and achieving productive utilization of atmospheric CO.

BACKGROUND

A 4-year field study, on the adoption of a Biologically-Enhanced Agricultural Management (BEAM) protocol, in a cotton/cover-crop rotation in Turkey, was designed to observe "change-over-time" of soil organic carbon (SOC%) and total soil nitrogen (TSN%) at three soil profile depths (0-15 cm, 15-30 cm and 30-45 cm) while tracking farm productivity and profitability.

METHODS

BEAM systems employ regenerative practices: (a) no-till, (b) no, or reduced synthetic nutrient amendments, (c) continuous roots in the ground (commodity/cover), accompanied with an injection (in-furrow at planting) of an extract of beneficial microbes, from a Johnson-Su bioreactor. Three field nitrogen treatments: (1) BEAM+100% N (203 kg N ha); (2) BEAM+15% N (30.53 kg N ha); and (3) BEAM-0% N (No N applied), were implemented, on a 5.22-hectare plot, to assess the influence of BEAM protocols and nitrogen amendments, on SOC%, TSN%, cotton production, and profitability.

RESULTS

The SOC%, in the 0-15 cm soil profile demonstrated a significant increase from 0.39% SOC to 1.83% SOC, for a total increase of 1.44%, over the 4-year study period, (y = 0.3136x + 0.1206; r = 0.96; F(1,2) = 45.1616, = 0.02143); The 15-30 cm soil profile demonstrated a non-significant loss of -0.23% SOC (y = -0.3161x + 0.156; r = 0.3183; F(1,2) = 0.9339, = 0.4358), and the 30-45 cm soil profile exhibited a significant increase of 0.28% SOC; (y = 0.0477x + 0.4743; r = 0.9363; F(1,2) = 29.4005, = 0.03237). Annual SOC cumulative increases of 6.59 metric tons (t) carbon (C) hayr, were observed, from 2019 to 2023, in the top 45 cm of the soil profile along with annual TSN increases of ~0.68 t N hayr in all three treatments. Cover-crop aboveground biomass increased annually in 2021, 2022 and 2023 from ~400 g, to ~692 g, to ~925 g dry biomass myr providing annual agroecosystem surface carbon accumulation of ~1.78 t C, ~3.08 t C and ~4.11 t C ha. Earthworm populations increased from zero earthworms m in 2019 to ~100 earthworms m in 2023. BEAM protocols also promoted: (a) farm input reductions of: 100% for herbicide, 56% for insecticide, 61% for diesel fuel, 85% for synthetic nitrogen fertilizer, and 100% for phosphorus fertilizer applications, reducing farm input costs ~$470 hayr. Adoption of a BEAM regenerative agricultural management system, increased: (a) SOC (6.59 t C hayr); (b) C in the annual growth of cover-crop biomass (4.12 t of C hayr); (c) carbon in residual surface cover-crop plant residues from previous annual cover crops (0.82 t C hayr); and (d) C exported in cotton lint (0.77 t C hayr). Total C avoidance included: (a) reductions in fertilizer, pesticides and diesel inputs (0.33 t C hayr); and (b) reduction of C respiration from adoption of zero-till (~0.64 t C hayr). Adoption of BEAM management, in this cotton/cover-crop agroecosystem, provided productive utilization, or avoidance of ~13.27 t of atmospheric C hayr.