There is a worldwide increase of heavy metal or potentially toxic element (PTE), contamination in agricultural soils caused mainly by human and industrial action, which leads to food contamination in crops such as in maize. Cadmium (Cd) is a PTE often found in soils and it is ingested through food. It is necessary to determine the bioabsorption, distribution, and accumulation levels in maize to reduce or prevent food chain contamination. Cadmium absorption and accumulation in three maize cultivars were evaluated in three agricultural environments in Chile by increasing CdCl₂ rates (0, 1, and 2 mg·kg⁻¹). Evaluation included Cd accumulation and distribution in different plant tissues, bioaccumulation factor (BAF), bioconcentration factor (BCF), translocation factor (TF), and tolerance index (TI). Cadmium whole-plant uptake was only affected by the CdCl₂ rate; the highest uptake was obtained with 2 mg·kg⁻¹ CdCl₂ (34.4 g·ha⁻¹) (p < 0.05). Cadmium distribution in the maize plant usually exhibited the highest accumulation in the straw (p < 0.05), independently of the environment, Cd rate, and evaluated cultivar. Given the results for TF (TF > 2) and BAF (BAF > 1), the Los Tilos and Chillán environments were classified as having a high capacity to contaminate the food chain for all evaluated cultivars.

The use of phosphate solubilizing bacteria (PSB) is an ecological strategy that allows for increasing the availability of phosphorus (P) in soil. The objective of this study was to evaluate P availability in wheat, in soils derived from volcanic ash (Andisol and Ultisol,) and inoculated with phosphate-solubilizing Bacillus thuringiensis, the experiment was conducted in pots under greenhouse conditions using a completely randomized design. Wheat plants were inoculated and re-inoculated at 20 and 46 days after sowing (DAS), respectively, with B. thuringiensis; and, soil and plant sampling was performed after 46, 66, and 87 days based on the Zadoks growth scale (Z). The inoculation resulted in an 11% increase in P of the rhizosphere at Z46 (Ultisol), P also increased 34% and 67% in aerial tissues at Z46 (Andisol and Ultisol), respectively, while an increase of 75% was observed in root tissues at Z87 (Ultisol). Similarly, the inoculation resulted in increases in acid phosphatase activity (Andisol), soil microbial biomass (Andisol and Ultisol), and root biomass in plants (Ultisol), without achieving increase of the aerial biomass of the plants. The phosphate solubilizing B. thuringiensis strain showed some positive, but also negative effects in soils and plants, depending on the soil.

Conservation agriculture using crop rotations and residue management is increasingly accepted in conventional agricultural systems. However, the effects on crop productivity and soil properties of different rotations, levels of use, and residue management have yet to be fully understood. Our study considered the effect of three previous crops (bread wheat, durum wheat, and corn) and four levels of residue incorporation (0%, 50%, 100%, and 200%) in a split plot design with four replicates on canola production parameters and soil chemical properties at the end of this crop. Production parameters and soil chemical properties were mostly affected by the previous crop and less by the residue incorporation rates under the conditions of this experiment; however, neither of these factors affected grain yield (ranging from 4.0 to 4.8 Mg ha⁻¹). Canola residue production was higher (9.7%) after the corn crop, regardless of the residue incorporation rate, but the harvest index was lower after this crop. Most of the soil chemical properties were also affected, revealing increased organic matter and exchangeable K when the previous crop was corn and decreased concentrations of the cations with basic reaction when the previous crop was durum wheat.

The increasing use of soils for agricultural purposes can expose some species that are important in the human diet, such as durum wheat (Triticum turgidum L. Var durum), to absorb cadmium (Cd) in soils with high concentrations of this metal, with subsequent risk in the human health. The development of genotypes with low Cd accumulation, as well as the study of field conditions of different cultivar combinations, Cd soil concentrations, and environments, can contribute in generating foods with low Cd accumulation. Field experiments were conducted in different agricultural zones in Chile (La Serena, Los Tilos, Chillán, and Temuco) with three durum wheat cultivars in soils where three increasing Cd rates were applied. Results indicated that applying Cd to the soil did not affect yield or biomass production in the plant. Cadmium accumulation in grains, straw, and roots was significantly affected by increasing Cd rates. Cadmium distribution in the plant was lower in the grains and straw and higher in the roots. Cadmium apparent recovery was lower than 0.8%, and it was not affected by the rate of soil Cd. All the evaluated parameters were influenced by the study location, and only some showed differences among cultivars. Of the three evaluated cultivars, only ‘Lleuque-INIA’ exhibited a Cd concentration that was lower than internationally characterized genotypes described as low Cd accumulators.

Blueberry exports that imply transport times of more than 25 d deteriorate their quality. The use of elicitors in preharvest has shown positive effects on the quality of berries such as grapes. The objective of this study was to evaluate preharvest applications (21, 14, and 7 d before harvest) of oxalic acid (OA) and salicylic acid (SA) on fruit firmness and phenolic compounds in blueberry. The treatments of 0, 2, and 4 mM OA in ‘Kirra’ and 0, 2, and 4 mM SA are in ‘Stella blue’. With the earlier preharvest application, ‘Kirra’ presented better firmness than ‘Stella blue’; however, 2 mM OA and SA in both cultivars increased fruit firmness, maintaining its weight and diameter with respect to the control. It should be noted that the treatment with 2 mM SA generated a 100% increase in polyphenolic content and antioxidant capacity (p < 0.05) in ‘Stella Blue’, with values close to 140 mg gallic acid 100 g⁻¹ and 80 mg 100 g⁻¹ fresh weight (FW), respectively. In Kirra, OA treatments did not have a significant impact on the polyphenol content, but 4 mM OA increased by 100% and 20%, total anthocyanin and antioxidant capacity of blueberry fruit, respectively. Based on our results, three pre-harvest applications of OA and SA during the fruit development until the beginning of ripening improve fruit firmness by up to 20% at different times of harvest.