On-farm research to assess the use of manure, woody-biomass and coal char as land treatment practices to improve agricultural soil health in Nebraska

In nearly every production environment, there are opportunities to capture profits if waste streams can be further processed or enhanced to create “value added” products. This study investigated the impacts on soil characteristics and crop productivity of three traditional “waste” streams: livestock manure, cedar mulch from forestry management and coal char from sugar beet production. On-farm research studies were initiated in 2019 at four locations across the state of Nebraska to assess the impacts of these amendments on agricultural cropland. Study treatments included beef cattle manure (CM), beef cattle slurry (CS), coal char (CC), woody biomass (WB), cattle manure+woody biomass (CMWB), cattle slurry+woody biomass (CSWB), and cattle manure+coal char (CMCC). Soil chemical properties (SOM, pH, CEC, EC, NO3-N, P, K, S04-S, Ca, Mg, Na), soil physical properties (aggregate stability, bulk density, sorptivity) and corn yield were evaluated. Results indicate that single pre-plant manure applications can make significant contributions of macronutrients (N, P and K), constituting a reliable resource to replace inorganic fertilizers. No changes in crop yield were observed with manure applications, having N balanced between treatments. Depending on initial soil quality, manure also increased SOM, pH, and EC. Surface applications of woody biomass did not show evidence of soil acidification or N immobilization, although it induced soil nitrate reduction in top soil layers when incorporated after crop harvest in one research site. Soil physical properties were mostly unchanged under all treatments except coal char. This treatment significantly increased SOM and pH, and decreased bulk density. However, it also decreased crop yield.