Quinoa is a strategic crop due to its high N content and its adaptability to adverse conditions, where most of the soils are deficient of nitrogen (N). The central question in this review was the following: How can quinoa yield low levels of nitrogen in the soils of Altiplano? This question was unraveled based on different factors: (1) fertilization effect on productivity, (2) fertilization limits, (3) uptake and assimilation of nitrogen parameters, (4) monoculture practice effect, and (5) possible sources and strategies. One hundred eleven articles of different scientific platforms were revised and data were collected. Information from articles was used to calculate the partial factor productivity for nitrogen (PFPN), the apparent use efficiency of N (APUE_N), available nitrogen (AN), and nitrogen content harvested in grains (HarvN). Quinoa responds positively to fertilization, but differences in yield were found among irrigated and rainfed conditions. Quinoa can produce 1850 kg grains ha⁻¹ with 50 kg N ha⁻¹ under irrigated conditions, and 670 kg grains ha⁻¹ with 15 kg N ha⁻¹ in rainfed conditions. Quinoa increases seed yield and HarvN increases N fertilization, but decreases nitrogen efficiency. In Altiplano, without nitrogen fertilizer, the quinoa yield relies on between 500 and 1000 kg ha⁻¹, which shows that in the soil, there are other nitrogen sources.

Throughout evolution, plants have developed different strategies of responses and adaptations that allow them to survive in different conditions of abiotic stress. Aloe vera (L.) Burm.f. is a succulent CAM plant that can grow in warm, semi-arid, and arid regions. Here, we tested the effects of preconditioning treatments of water availability (100, 50, and 25% of soil field capacity, FC) on the response of A. vera to prolonged drought growing in the hyper-arid core of the Atacama Desert. We studied leaf biomass, biochemical traits, and photosynthetic traits to assess, at different intervals of time, the effects of the preconditioning treatments on the response of A. vera to seven months of water deprivation. As expected, prolonged drought has deleterious effects on plant growth (a decrease of 55–65% in leaf thickness) and photosynthesis (a decrease of 54–62% in E_max). There were differences in the morphophysiological responses to drought depending on the preconditioning treatment, the 50% FC pretreatment being the threshold to better withstand prolonged drought. A diurnal increase in the concentration of malic acid (20–30 mg mg⁻¹) in the points where the dark respiration increased was observed, from which it can be inferred that A. vera switches its C3-CAM metabolism to a CAM idling mode. Strikingly, all A. vera plants stayed alive after seven months without irrigation. Possible mechanisms under an environmental context are discussed. Overall, because of a combination of morphophysiological traits, A. vera has the remarkable capacity to survive under severe and long-term drought, and further holistic research on this plant may serve to produce biotechnological solutions for crop production under the current scenario of climatic emergency.

The broad distribution of quinoa in saline and non-saline environments is reflected in variations in the photosynthesis-associated mechanisms of different ecotypes. The aim of this study was to characterize the photosynthetic response to high salinity (0.4 M NaCl) of two contrasting Chilean genotypes, Amarilla (salt-tolerant, salares ecotype) and Hueque (salt-sensitive, coastal ecotype). Our results show that saline stress induced a significant decrease in the K⁺/Na⁺ ratio in roots and an increase in glycine betaine in leaves, particularly in the sensitive genotype (Hueque). Measurement of the photosynthesis-related parameters showed that maximum CO₂ assimilation (A_max) in control plants was comparable between genotypes (ca. 9–10 μmol CO₂ m⁻² s⁻¹). However, salt treatment produced different responses, with A_max values decreasing by 65.1% in the sensitive ecotype and 37.7% in the tolerant one. Although both genotypes maintained mesophyll conductance when stomatal restrictions were removed, the biochemical components of Amarilla were impaired to a lesser extent under salt stress conditions: for example, the maximum rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO; V_cmax) was not as affected in Amarilla, revealing that this enzyme has a higher affinity for its substrate in this genotype and, thus, a better carboxylation efficiency. The present results show that the higher salinity tolerance of Amarilla was also due to its ability to control non-diffusional components, indicating its superior photosynthetic capacity compared to Hueque, particularly under salt stress conditions.

The abandonment of ancestral techniques and the incorporation of new technologies in the production systems for the cultivation of quinoa has resulted in overexploitation of soils, a loss of fertility, water imbalance, a loss of native vegetation cover in plain land areas, and other negative effects on the southern Altiplano agricultural sustainable system. One of the methods to reduce wind erosion and improve soil environmental conditions is establishing a native vegetative barrier. The effect of t’ola [Parastrephia lepidophylla (Wedd.) Cabrera] as a vegetative barrier to prevent wind erosion was evaluated using the rod method, gravimetric humidity fluctuations, and soil quality measurements in traditional quinoa Real production plots. We found significant differences (p < 0.05) for mean erosion, sedimentation, net erosion, and mobilized soil variables. The highest loss of soil was reported for December and November. Vegetative barriers comprising three meters of t’ola better protected bare soils up to 7 m from the barrier, while in bare soils, the loss values were over 5 t ha⁻¹ month⁻¹. Soil humidity fluctuations in plots with t’ola vegetative barriers were highly significant for the distance factors and depth levels. There was a higher accumulation of gravimetric humidity (%) in bare soils from 1.5 m to the barrier (6.95%), while the insides of the vegetative barriers retained an average soil humidity of 6.37%. After two agricultural seasons in the quinoa plots, 62 t ha⁻¹ per year of soils were lost due to a lack of vegetative barriers. Due to the large, cultivated area with quinoa (104,000 ha in 2014) in the Intersalar zone, wind erosion causes 6.48 million tons of soil loss yearly. T’ola vegetative barriers in the southern Altiplano of Bolivia favour the retention of sediments against wind erosion and soil protection for quinoa cultivation. Furthermore, incorporating native lupine increased soil fertility by 80% and protected the soil surface cover.

Quinoa ( Chenopodium quinoa Willd.) is increasingly cultivated in marginal environments; however, early-season frosts pose a major constraint to successful stand establishment. Despite evidence of genotypic variation in cold tolerance, the effects of short, occasional frost events occurring at specific germination stages remain poorly understood. We evaluated the impact of single, occasional frost events (0, −2, and −4 °C) applied during distinct germination phases: Phase I (imbibition, 4 h), Phase II (absorption, 2 h), and Phase III (radicle protrusion, 6 h), in two Chilean quinoa cultivars (Roja and Amarilla). Across four replicates (50 seeds per cultivar per treatment), we quantified germination percentage and rate, imbibition rate, osmotic potential (Φ), and proline content under controlled conditions. The main results were: Frost exposure during Phases I and II markedly reduced final germination, frequently causing reductions greater than 70% relative to the control, with the strongest inhibition observed at −4 °C during Phase I. In contrast, when frost was applied during Phase III, germination was less affected and generally remained above 50%, indicating clear phase-dependent tolerance. Frost conditions reduced imbibition rate and induced a more negative osmotic potential, accompanied by increased proline accumulation, particularly at −4 °C during Phases II and III. Amarilla showed higher germination than Roja when frost was applied during Phase III, revealing cultivar-specific responses. These findings demonstrate that the first hours following sowing constitute a critical sensitivity window to occasional frost in quinoa. Phase-specific physiological responses, including osmotic adjustment, appear to play a protective role under freezing stress. The observed cultivar differences highlight exploitable genetic variation and provide valuable information for improving sowing management and breeding strategies under increasing climatic variability.