Comparison of Cover Crop Termination Methods on Soil Microbial Communities and Soil Enzymes
ASA, CSSA, SSSA International Annual Meeting
Different termination methods of cover crop will produce varying quantities of organic residue which will affect microbial diversity and soil enzymes. The experiment aimed to compare termination methods such as flail mowing, sickle bar mowing, roller-crimper, rotary mowing, and occultation using black tarps for fall-grown cover crop combination (hairy vetch-cereal rye) to determine the ...
Different termination methods of cover crop will produce varying quantities of organic residue which will affect microbial diversity and soil enzymes. The experiment aimed to compare termination methods such as flail mowing, sickle bar mowing, roller-crimper, rotary mowing, and occultation using black tarps for fall-grown cover crop combination (hairy vetch-cereal rye) to determine the effects on soil microbial diversity and soil enzymes. Field experiments were conducted for three consecutive years (2018-2021). The presence of cover crops increased microbial biomass (indicated by total PLFA concentration) relative to the control. The total PLFA analysis showed about a 24% increase for flail mowed, 17% for rotary mowed, and 15% for sickle bar mowed termination methods respectively. The results for bacterial PLFA indicated that flail mowed showed the highest increase (32.7 nmol g-1 soil) for Gram-positive, and (44.8 nmol g-1 soil) for Gram-negative bacteria compared with control. The other microbial groups including actinomycetes, arbuscular mycorrhizal fungi (AMF), fungi, and eukaryotes were highest for flail mowed followed by rotary mowed termination. The activities of all seven enzymes studied were significantly increased with cover crop v/s no cover crop treatment. Sickle bar mowing showed the highest activity for acid phosphatase followed by flail mowing, each with almost two-three times increase in activity compared with control. Arylsulfatase showed the highest activity with occultation followed by flail mowing. The beta-glucosidase activity was increased by 54% with flail mowing and followed by occultation. The activities of b-glucosaminidase and dehydrogenase were highest with the sickle bar mowed treatment. Peroxidase and phenol-oxidase activities also varied with termination methods with the highest activity reaching by rotary mowed for peroxidase. In this study, flail mowing was found best cover crop termination method to enhance soil microbial and enzymatic activity.
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