Long‐term ground cover affects soil bacterial community and carbon metabolism in the Loess Plateau, China

Abstract

Farmland mulching can maintain soil nutrients, which plays a positive role in agricultural planting in the arid area. However, the composition of the soil microbial community and the C cycle involved is unclear under farmland mulching. Based on the Changwu Agro-Ecological Experiment Station, this study set up a long-term positioning experiment to explore the effect on soil bacterial community structure and C metabolism capacity. In this study, we include five treatments: control uncovered (CK), plastic film mulching (PF), high amount of straw mulching carried out in July, August, and September every year (St 90 ), low amount of straw mulch throughout the growth period (S 45 ), and high amount of straw cover throughout the growth period (S 90 ). We combined Illumina MiSeq sequencing and Biolog-ECO technology to analyze the functional characterization of soil bacterial community composition in terms of C source metabolism. The results indicated that the soil bacteria showed a high degree of epistatic clustering, and the operational taxonomic unit numbers of soil bacteria decrease as St 90 , S 45 , PF, CK, and S 90 . Redundancy analysis showed that soil available P, NH 4 + -N, soil moisture content were the main environmental factors affecting bacterial community composition. Proteobacteria, Acidobacteria, and Actinobacteria are the main dominant flora in this area. Soil bacterial C metabolism was highest under PF treatment. Structural equation modeling (SEM) shows that surface cover has direct and indirect effects on bacterial C metabolism capacity and diversity through soil physicochemical properties. Reasonable mulching methods have a positive effect on the sustainable development of agro-ecosystems in arid areas. Abbreviations: AP, available phosphorus; AWCD, average well color development; CK, control uncovered; MC, soil moisture content; MFC, soil maximum water holding capacity in the field; NH 4 + -N, soil ammonium nitrogen; NO 3 − -N, nitrate-nitrogen; OTU, operational taxonomic units; PF, plastic film mulch; RDA, redundancy analysis; S 45 , low amount of straw mulch throughout the growth period; S 90 , high amount of straw cover throughout the growth period; SEM, structural equation modeling; SOC, soil organic carbon; St 90 , high amount of straw mulching is carried out in July, August, and September; TC, total carbon; TN, total nitrogen; TP, total phosphorus.

Late topdressing can sustain wheat grain yield under straw mulching in the Loess Plateau of China

“…Nitrogen is the primary factor affecting crop growth and grain yield (Osmond & Riha, 1996). In the present study, straw mulching decreased soil mineral N levels at later growing stages both in 2018 and 2019 (Table 2), which was consistent with Wicks et al (1994) and W. Zhang et al (2022). First of all, the high C/N ratio under wheat residues (generally >60) and the relatively large amounts of readily decomposable C compounds leads to prolonged N immobilization by microorganisms (Rusinamhodzi et al, 2011).…”

Response of the tomato rhizosphere bacterial community to water–oxygen coupling under micronanobubble oxygenated drip irrigation in mildly saline soil

“…Furthermore, soil salinization also directly affects microbial metabolic functions, such as by reducing the abundance of glycosyltransferase and glycoside hydrolase genes and decreasing carbohydrate metabolism (Zuluaga et al, 2021). Many studies have used biochar, organic fertilizer, and soil mulch to improve the physical environment of saline soils to regulate the microbial community structure and metabolic function (Manasa et al, 2020; W. Zhang et al, 2022; L. Zhu et al, 2021). However, all of these measures are indirect regulation measures, and their effects are relatively slow.…”