UC Davis

Anthropogenic activities leading to erosion-induced topsoil loss still present a pertinent threat to maize (Zea mays L.) productivity across the U.S. Corn Belt region. Using soil amendments has been proven effective in reversing the effects caused by erosion-induced topsoil loss and restoring agronomic productivity and yields to pre-eroded conditions. The current study investigated the impact of simulated erosion and repeated amendment application on agronomic productivity and yields over five growing seasons for a 23-year-old experiment at two central Ohio sites (Waterman Farm: WF; Western Station: WS). Simulated erosion/deposition was employed in 1997 to create three incremental topsoil depths (TSD) (20 cm topsoil removed (TSD-0); 0 cm topsoil removed (TSD-1); 20 cm topsoil added (TSD-2). Three soil amendments (inorganic, synthetic N fertilizer (INO); organic, compost manure (MAN); no amendment (CON)) were investigated for their ability to restore productivity in these cropping systems. Greater TSD produced higher germination counts and crop stand and yielded greater canopy cover during the initial five weeks after germination. The MAN amended soils observed higher values for the productivity parameters during the 2016–2020 growing seasons. Grain and biomass yields were 34–51% and 5–12% lower, respectively, for the TSD-0 level and 4–10% and 3–6% greater, respectively, for the TSD-2 level when compared to the undisturbed, TSD-1 level. Relative biomass yield losses (% per cm topsoil depth lost) were 0.921 for the WF site and 0.254 for the WS site, corresponding to average biomass losses (Mg ha−1 cm−1 yr−1) of 0.083 and 0.026 for each site. Relative grain yield losses (% per cm topsoil depth lost) were 1.29 for the WF site and 0.514 for the WS site, equating to mean grain losses (Mg ha−1 cm−1 yr−1) of 0.083 and 0.026 for each site. The rehabilitative capacity of the soil amendments followed a trend of INO > MAN at the WF site and MAN > INO > CON at the WS site. The deleterious effects of erosion on grain and biomass yields were found to be reversed with the addition of the INO and MAN amendments at the WS site due to improvements in soil health and SOC pools. The MAN amended soils produced grain and biomass yields that were nearly 2.5% and 5.6% greater than the INO amended soil when compared to the reference treatment (TSD-1-CON). This study demonstrates that sustainable soil management practices coupled with annual soil amendment addition can mitigate the deleterious effects of erosion and rebound maize yields to pre-eroded conditions for soils experiencing severe topsoil loss.