Mechanism of Intermittent Deep Tillage and Different Depths Improving Crop Growth From the Perspective of Rhizosphere Soil Nutrients, Root System Architectures, Bacterial Communities, and Functional Profiles

Yabing Gu; Yongjun Liu; Jiaying Li; Mingfeng Cao; Zhenhua Wang; Juan Li; Delong Meng; Peijian Cao; Shuhui Duan; Mingfa Zhang; Ge Tan; Jing Xiong; Huaqun Yin; Zhicheng Zhou

doi:10.3389/fmicb.2021.759374

Mechanism of Intermittent Deep Tillage and Different Depths Improving Crop Growth From the Perspective of Rhizosphere Soil Nutrients, Root System Architectures, Bacterial Communities, and Functional Profiles

Front Microbiol. 2022 Jan 10:12:759374. doi: 10.3389/fmicb.2021.759374. eCollection 2021.

Authors

Yabing Gu¹, Yongjun Liu^{2

3}, Jiaying Li⁴, Mingfeng Cao⁵, Zhenhua Wang⁶, Juan Li², Delong Meng¹, Peijian Cao⁷, Shuhui Duan³, Mingfa Zhang⁸, Ge Tan¹, Jing Xiong¹, Huaqun Yin¹, Zhicheng Zhou³

Affiliations

¹ School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
² College of Agronomy, Hunan Agricultural University, Changsha, China.
³ Tobacco Research Institute of Hunan Province, Changsha, China.
⁴ Yongzhou Tobacco Company of Hunan Province, Yongzhou, China.
⁵ Changde Tobacco Company of Hunan Province, Changde, China.
⁶ Zhangjiajie Tobacco Company of Hunan Province, Zhangjiajie, China.
⁷ China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, China.
⁸ Xiangxizhou Tobacco Company of Hunan Province, Jishou, China.

Abstract

Long-term conventional shallow tillage reduced soil quality and limited the agriculture development. Intermittent deep tillage could effectively promote agricultural production, through optimizing soil structure, underground ecology system, and soil fertility. However, the microecological mechanism of intermittent deep tillage promoting agriculture production has never been reported, and the effect of tillage depth on crop growth has not been explored in detail. In this study, three levels of intermittent deep tillage (30, 40, and 50 cm) treatments were conducted in an experimental field site with over 10 years of conventional shallow tillage (20 cm). Our results indicated that intermittent deep tillage practices helped to improve plant physiological growth status, chlorophyll a, and resistance to diseases, and the crop yield and value of output were increased with the deeper tillage practices. Crop yield (18.59%) and value of output (37.03%) were highest in IDT-50. There were three mechanisms of intermittent deep tillage practices that improved crop growth: (1) Intermittent deep tillage practices increased soil nutrients and root system architecture traits, which improved the fertility and nutrient uptake of crop through root system. (2) Changing rhizosphere environments, especially for root length, root tips, pH, and available potassium contributed to dissimilarity of bacterial communities and enriched plant growth-promoting species. (3) Functions associated with stress tolerance, including signal transduction and biosynthesis of other secondary metabolites were increased significantly in intermittent deep tillage treatments. Moreover, IDT-30 only increased soil characters and root system architecture traits compared with CK, but deeper tillage could also change rhizosphere bacterial communities and functional profiles. Plant height and stem girth in IDT-40 and IDT-50 were higher compared with IDT-30, and infection rates of black shank and black root rot in IDT-50 were even lower in IDT-40. The study provided a comprehensive explanation into the effects of intermittent deep tillage in plant production and suggested an optimal depth.

Keywords: ecosystem function; intermittent deep tillage (IDT); rhizosphere bacterial community; root system architecture (RSA); sustainable agriculture.