**3.3 Use of brine in halophyte plant cultivation under the principles of circular economy**

The use of brines in saline agriculture can be beneficial, as it reduces the current demand for food production and maximizes water resources and the use of saline soils in accordance with the three principles of the circular economy (optimizing resources, maximizing the utility of materials, and preserving natural capital).

Today, it is possible to find salt-tolerant crops such as halophytes. These plants have developed a series of physiological and morphological adaptations that allow their tolerance to salt, and although they represent only 2% of terrestrial plant species, their domestication and cultivation in a context of saline agriculture may be interesting to consider [45].

Among the halophyte plants is the forage shrub *A. nummularia* (**Figure 1**), which grows in conditions of high salinity, requires little water, and has similar chemical properties to alfalfa. Despite being a shrub native to Australia, it is also grown in Chile, mainly in the north and can reach 3.5 m in height, is a common forage species in arid and semiarid regions, due to its tolerance to drought and salinity, can grow or can be planted in soil and/or saline water, and is also used as feed for bovine livestock [46].

In addition, there are studies in Brazil where they have cultivated forage plants irrigated with brine (obtained from RO), indicating that the yield for *A. nummularia* was 5.5–8.5 t. ha year<sup>1</sup> . The amount produced from the halophilic plant using brine is much higher than the value obtained in other arid parts of South America where it is grown as a wild crop [20, 47].

**Figure 1.** *Forage crop* Atriplex nummularia *[46].*
