Cover crop and tillage effects on soil microbial communities in a corn cropping system

Abstract

Soil microbial communities have numerous soil ecological and physiological functions. However, knowledge is lacking on the interaction effects of no-till and cover crops (CC) practices on these soil health indicators. This study evaluated the effects of CC and tillage on soil microbial communities in a corn (Zea mays L.) system. The study was conducted for 2 consecutive years on plots allotted to three practices: (1) no-till and cover crop (NC), (2) conventional till and no cover crop (CN), and (3) no-till no cover crop (NN). A grass strip (G) was used as a reference, assuming it was subjected to the least disturbance. Surface (0–5 cm and 5–10 cm) soils were sampled over 2 years in April and October. Soil microbial biomass was measured using phospholipid fatty acid (PLFA) analysis. Seasonal variations indicated greater microbial biomass in fall than in spring. The G and NC significantly increased soil microbial biomass at both depths compared to CN and NN during fall 2021 sampling and numerically in fall 2020, where greater changes were observed at 0- to 5-cm depth. In fall 2021 sampling, NC practices had 65%–75% more total microbial biomass than CN and NN at both depths (p < 0.001), with total bacterial biomass 70% greater (p < 0.002) and total fungal biomass 75%–85% greater (p < 0.007). NC also showed 85% more actinomycetes biomass than CN at 5- to 10-cm depth (p < 0.05). The study concluded that soil microbial communities significantly improved after two CC seasons, with higher microbial biomass in fall compared to spring.