Location: Soil Management ResearchTitle: Quantifying improvements in water stable aggregation due to stover retention
|OJEKANMI, ABIMBOLA - Orise Fellow|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/10/2021
Publication Date: N/A
Technical Abstract: The material remaining after harvesting corn (Zea mays L.), which is often call stover, might be harvested for bioenergy feedstock, animal food or bedding, or recycled to the soil. Harvesting for any reason will reduce the mass of stover returned to the soil. Healthy soils are characterized by having water-stable aggregates (WSA), which are formed by interactions among soil particles, plant and microbial products. Stover management and tillage choice can impact WSA formation by altering the amount of plant material decomposing and supporting the microbial biomass. The impact of stover harvest on aggregate formation was studied independently in two fields one managed with annual fall chisel plowing (CP) and the other without tillage (NT). Both fields were in a corn/soybean (Glycine Max. L. [Merr.]) rotation with four rates of corn stover retention treatments: harvesting only grain (Grain), grain plus cobs (Grain+Cob), grain plus about half the stover (Grain+Moderate) and grain plus as much stover as possible (Grain+Aggressive), returning about 8, 5, 4 and 2 Mg ha-1 yr-1 dry stover, respectively. The aggregate size distribution of WSA and the mean weight diameter (MWD) were determined on clay loam/loam Mollisol collected at 0-5 and 5-10 cm. Treatments, crop phase, soil depth, and interactions were analyzed using a mixed linear model. Linear regression was used to assay relationships between WSA, and stover mass retained. In both fields, Grain+Aggressive had the lowest WSA, MWD, and fewer aggregates =2-mm compared treatments. In the CP and NT fields, WSA increased by 0.85% and 2.25% per Mg stover returned, respectively. Harvesting stover reduced the formation and/or the maintenance of stable aggregates; thereby, reduced their ability to resist the erosive force of water.