1. Introduction
Due to global climate change and increasing population pressure, 33% of
global soil is moderately to highly degraded through erosion,
salinization, compaction, acidification, chemical pollution, and
nutrient depletion, hampering soil functions and affecting food
production (Abogadallah, 2010; Mao et al., 2016). Soil salinization
causes damage not only to natural resources, but is also a major factor
restricting the development of agricultural production and improving
land-use efficiency, and is also a threat to organisms and ecosystems
(Liu et al., 2018; Yu, Liu, Yang, Fan & Zhou, 2018; Xia, Ren, Zhang,
Wang & Fang, 2019). Nevertheless, saline soils are widely distributed
on the earth surface, covering approximately 7-8% of the world land
area, making them a potentially important land resource (Shrivastava &
Kumar, 2015; Jiang et al., 2019).
In saline soils, salinity as well as alkalinity damage plant roots very
seriously. Roots play an important role in plant growth. Roots extract
nutrients and water from soil, and also exude a variety of organic and
inorganic compounds into the rhizosphere soil. These exuded compounds
change the chemistry and biology of the rhizosphere soil, making it
significantly different from the bulk soil further away from roots
(Marschner, 1995; Zhang, Li, & Wang, 2007). Plants form a specific
bacterial community structure in the rhizosphere soil through specific
root exudation, and the secondary metabolites produced by some
rhizosphere bacteria can promote plant growth (Sturz & Christie, 2003).
Furthermore, soil microbes also play an important role in maintaining
the stability of ecosystems; they reflect the evolution of soil quality
and are one of the indicators of the ecosystem health (Diacono &
Montemurro, 2010).
Jerusalem artichoke (Helianthus tuberosus L.), which belongs to
the Asteraceae family, is a tuber-forming perennial distributed
worldwide (Shi et al., 2011). Jerusalem artichoke is an excellent crop
because it has strong resistance to abiotic stresses (drought, salinity,
etc.), high photosynthetic efficiency, low fertilizer and water demand,
great ecological restoration capacity, and high commercial value. It is
easily grown in saline and alkaline soils, and it can also be used for
soil and water conservation and fixing terraces and unstable sand (Long
et al., 2010; Shao et al., 2019).
In this paper, we aimed to explore an in situ remediation
technology using Jerusalem artichoke to improve the micro-ecological
environment of saline soils varying in salinity in the southeast China.
Through the quantification of the area of root channels, rhizosphere
secretions and soil microbiome, the change of carbon and nitrogen in the
saline soil was analyzed, and the modifying effect of Jerusalem
artichoke cultivation on the micro-ecological rhizosphere environment in
saline soil was elucidated.