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In recent years, there has been great interest in sustainable construction, which has led to an increased interest in 3D printing or additive manufacturing. However, the use of this technique with conventional materials is not enough to reduce the large environmental impact generated by the construction sector. Although most of the research and advances are focused on the 3D printing of Portland concrete, this review has been oriented towards the 3D printing of building materials based on soils and clays, which can provide an affordable (as it is a locally available material in many regions of the planet), environmentally sustainable, and low-cost approach, which is highly beneficial for housing construction. This paper has been oriented towards the search of scientific literature and prototypes that have been elaborated using ancestral materials, such as soil-clay-sand-sand-fibers like straw and water, for the elaboration of constructive pieces such as 3D printed walls or adobes. The objective of this paper is to close the gap on the use of mixtures based on soils, which, although they seem to have been fully studied for several centuries, to date their application in 3D printing is reduced. Readjustments in properties of soil mixtures such as fluidity for pumping or extrusion, buildability and good working time are variables that are reported in this paper. In addition, this review describes the mixtures that have been developed for 3D printing from soils and clays, and the main characteristics that have been found. Finally, the challenges that still remain for the blends to be applied on a massive industrial scale are presented. [ABSTRACT FROM AUTHOR]

The application of nitrogen-fixing microorganisms has shown benefits in plant nutrition. This research aimed to evaluate the effect of the application of nitrogen-fixing microorganisms on the growth of corn (Zea mays L.) crops. The experiment used a randomized complete block design (RCDB), with three repetitions. The treatments applied were: T1 - Paenibacillus polymyxa 2 L ha-1; T2 - P. polymyxa 3 L ha-1; T3 - P. polymyxa 4 L ha-1; T4 - Azotobacter chroococcum 2 L ha-1; T5 - A. chroococcum 3 L ha-1; T6 - A. chroococcum 4 L ha-1; T7 - P. polymyxa + A. chroococcum 2 L ha-1; T8 - P. polymyxa + A. chroococcum 3 L ha-1; T9 - P. polymyxa + A. chroococcum 4 L ha-1 y T10 - Control (without application). The variables evaluated were: plant height, stem diameter and insertion of the cob. The results showed that at 55 days after sowing (DDS) of the crop, good growth was obtained in the corn plants with a height of 182.01 cm and stem diameter of 20.14 mm with the application of the T9 - P. polymyxa + A. chroococcum. In addition, the insertion of the cob was also at 120 cm in height, for this same treatment. [ABSTRACT FROM AUTHOR]

Copyright of Revista Numismática Hécate is the property of Revista Numismatica Hecate and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Terra Latinoamericana is the property of Sociedad Mexicana de la Ciencia del Suelo A.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purple corn (Zea mays L.) which background is the Kculli race, was originated in the Andean region and is grown in environments as high as 3000 m.a.s.l.; it is unique because of the purple color in the grain and other parts of the plant; the color is due to the presence of anthocyanin such as cianidine-3- glucoside. The objective of this study was to evaluate the grain production and determine the anthocyanin content in the cob and husk of six purple maize cultivars. Anthocyanin content in cob and husk was obtained through the pigment absorbance determination by HPLC (High Performance Liquid Chromatography). Cultivars were planted at 28 environments of Cajamarca during 2016 to 2019. Results indicated that cultivar INIA 601 showed the highest grain yield (2.77 t ha-1) and the highest anthocyanin content in cobs (6.12) and husks (3.18 mg/cianidine-3-glucoside); consequently, using this technology, farmers can develop an agribusiness four times more profitable than growing other types of maize for grain production. [ABSTRACT FROM AUTHOR]

Salicylic acid (AS) may modulate several physiological and biochemical processes in plants, and may contribute to improve crop yield. These processes are also induced in maize (Zea mays) cultivation, but their effects on bioproductivity are not very well known. Therefore, we evaluated the effect of applying AS to maize leaves on growth, nutrient status, and yield of the local variety Xmejen-nal, State of Yucatan, Mexico. We conducted two independent experiments with randomized complete block designs, under field conditions, using two AS concentrations, 0.1 and 1 μM, and distilled water as control. Seven day-old plants were sprayed daily with this solution, for a week. The following variables were measured during harvest: plant height and diameter; above-ground dry biomass; cob diameter, length, and weight; grain yield (g plant-1); nitrogen, phosphorus (P2O5) and potassium (K2O) content, in above-ground tissue and grain. Applying 1 μM of AS increased (p£0.05) grain yield per plant, total dry biomass, and N, P2O5 and K2O content. Additionally, spraying maize plants with 1 μM and 0.1 μM AS resulted in 29 and 21 % increases (p£0.05) in cob length, respectively, as compared to the control. Grain yield showed a highly significant and positive correlation with all cob variables, suggesting that the increase of grain yield may be linked with the effect of AS on the cob. [ABSTRACT FROM AUTHOR]

Copyright of Polis (07176554) is the property of Polis - Revista Academica Universidad Bolivariana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)