Growing-season soil microbial respiration response to long-term no tillage and spring ridge tillage

Abstract

No tillage (NT) and spring ridge tillage (SRT) are two common applications of conservation tillage. Although conservation tillage is known to exert major control over soil microbial respiration (SMR), the growing-season SMR response to these two applications remains elusive. In order to better understand the influence of conservation tillage practices, this experiment was conducted in an experimental field using NT and SRT for 17 years. In situ measurements of SMR, soil temperature and soil water content (SWC) were performed. Soil samples were collected to analyze soil porosity, soil microbial biomass (SMB) and soil enzymatic activities. Results show that the two conservation tillage systems had a significant difference (p<0.05) in terms of SMR; the SMR of NT was 14.7 mg•C/m 2 •h higher than that of SRT. In terms of soil temperature and soil enzymatic activities, the two treatments were not significantly different (p>0.05). Despite SRT increasing the proportion of micro-porosities and meso-porosities, the soil macro-porosities for NT were 7.37% higher than that of SRT, which resulted in higher bacteria and fungi in NT. Owing to SRT damaged the hypha, which had disadvantage in soil microbe protection. Inversely, less soil disturbance was a unique advantage in NT, which was in favor of improving soil macro-pores and SWC. Redundancy analyses (RDA) showed SMR was positively correlated with soil macro-pores, SMB and SWC. Furthermore, the Pearson correlation test indicated that SMB and soil enzymatic activities did not have a significant correlation (p>0.05). This study results suggest that SRT is more conducive to carbon sequestration compared with NT in cropland.

Distribution of Soil Organic Carbon Density Fractions in Aggregates as Influenced by Salts and Microbial Community

“…The proportion of MOM carbon (types C, F, and I) exceeded that of POM and LF. Limited aeration within microaggregates inhibited microbial activity and was responsible for the high values of MOM carbon proportion [37,38]. An increase in salt levels with cultivation years of greenhouse enhanced organo-mineral associations within microaggregates [9,39,40].…”

Changes in Soil Microbial Parameters after Herbicide Application in Soils under Conventional Tillage and Non-Tillage

“…Conservation tillage generally promotes higher microbial activity, as the accumulation of organic residues in the topsoil and minimal soil disturbance increase its carbon concentration, which correlates positively with microbial biomass and microbial communities. An increase in soil organic carbon (OC) under these conditions creates a stable bacterial network and greater microbial diversity, raising enzyme activity levels and increasing microbial metabolic activity under conservation agriculture compared to conventional management [4,5]. In addition, Panettieri et al [6] have shown that non-tillage increases the quantity of soil fungi over bacteria, and Li et al [7] have reported a significant increase in the microbial population, fungal biomass, and bacterial diversity with non-tillage compared to conventional tillage.…”