4.1 Effect of quinoa cultivation on soil physicochemical
properties
Quinoa is an apomictic halophyte (Razzaghi et al., 2012) with salt
glands or salt capsules, i.e. special epidermal cells that can isolate
or exclude excess salt from metabolically active cells (Liphschitz and
Waisel, 1982). In the present study, the soil salinity increased in the
soil that had been planted with quinoa compared to the unplanted soil
(CK), and the salt content of high-density rhizosphere soil (HDR)
increased most significantly compared to CK. Nicole Goehring et al
(Goehring et al., 2019) estimated quinoa biomass production and soil
salinity with different irrigation managements and salinities, and the
root zone salinity increased in all treatments, which was consistent
with the results of this experiment. Zhang studied Puccinellia
ciliata (a salt-tolerant species) through greenhouse experiments and
found that salt accumulation also occurred between the roots of
salt-tolerant species on saline soils (Zhang et al., 2005). It is
suggested that quinoa continually effluxed salt from roots, contributing
to increased salinity in the rhizosphere soil, especially in
high-density planting (Fig. 1a). Therefore, cultivation of quinoa
requires adequate water supply and drainage to remove salt from the soil
in the high-density planting area and avoid inhibition of quinoa growth
due to salt accumulation.