Rare earth elements (REE) are a homogenous group of 17 chemical elements in the periodic table that are key to many modern industries including chemicals, consumer electronics, clean energy, transportation, health care, aviation, and defense. Moreover, in recent years, they have been used in agriculture. One of the consequences of their worldwide use is the possible increase of their levels in various environmental compartments. This review addresses major topics concerning the study of REE in the soil environment, with special attention to the latest research findings. The main sources of REE to soils, the contents of REE in soils worldwide, and relevant information on the effects of REE to plants were explored. Ecological and human health risk issues related to the presence of REE in soils were also discussed. Although several findings reported positive effects of REE on plant growth, many questions about their biological role remain unanswered. Therefore, studies concerning the actual mechanism of action of these elements on cellular and physiological processes should be further refined. Even more urgent is to unveil their chemical behavior in soils and the ecological and human health risks that might be associated with the widespread use of REE in our modern society.
Palavras-chave: Artemisia vulgaris, plantas medicinais, intensidade de luz, qualidade de luz
ABSTRACT: Biometric, anatomical and physiological aspects of Artemisia vulgaris L. grown under colored screens.The use of colored screens represents a new agricultural concept, which combines the plant physical protection with the solar radiation selective filtration to obtain expected light-regulated physiological responses. The aim of this work was to verify the effect of shading using colored screens on biometric, anatomical and physiological characteristics of Artemisia vulgaris. Plants were grown in pots kept in a completely randomized distribution, and treatments consisted of red and blue Cromatinet-type (50%) screens, besides full sun (without screen). The studied variables were more affected by light intensity than by light spectral quality. Stem diameter and starch grain number were not influenced by treatments, whereas height, root:shoot ratio, leaf thickness, and chlorophyll and carotenoid content were influenced by light intensity. Leaf area, plant dry matter and chloroplast number were affected by both light intensity and spectral quality.
The aim of this research was to evaluate the spatial distribution of bedding variables in a climate-controlled compost bedded pack barn (CBP) equipped with an evaporative cooling system associated with a tunnel ventilation mode. The study was conducted on a farm in the West Mesoregion of Minas, MG, Brazil. The interior of the animal facility was divided into a mesh of 120 equidistant points, where the bedding surface temperature (t b-sur ), the bedding temperature at 0.20 m depth (t b-20 ) and the bedding penetration resistance (PR b ) of layer 0 to 0.20 m depth were measured. Bedding samples were collected to obtain the moisture (M b ) and pH in the surface and at 0.20 m depth. Geostatistics technique was used to evaluate the dependence and spatial distribution. Through the bedding area, the t b-sur presented low variability, with 6 ºC of amplitude, and t b-20 presented highest values (up to 55 °C). The spatial distribution of M b-20 was similar to that observed on the surface and its highest levels occurred in the region near the feed alley (> 40%). The distribution of pH was similar in both layers. The tendency of high PR b occurred in the layer between 0.15 and 0.20 m (0 and 1500 kPa).
The objective of this study was to characterize the dependence and spatial distribution of bedding attributes in an open compost-bedded pack barn (CBP) system with positive pressure ventilation during the winter period in Brazil. The study was conducted in July 2021, in the Zona da Mata region, Minas Gerais, Brazil. The bedding area (shavings and wood sawdust) was divided into a mesh with 44 equidistant points. At each point, the bedding temperature at the surface (tB-sur) and at a depth of 0.2 m (tB-20) and the air velocity at bedding level (vair,B) were measured, and bedding samples were collected. The bedding samples were used to determine the moisture level and pH at the surface (MB-sur e pHB-sur) and at a depth of 0.2 m (MB-20 and pHB-20). The spatial behavior of the variables was evaluated using geostatistics techniques. For all variables, the occurrence of strong spatial dependence was verified. Through the maps, it was observed that tB-sur, tB-20, MB-sur, MB-20, and vair,B showed high spatial variability, whereas pHB-sur and pHB-20 demonstrated low variation. On the surface, values of tB-sur < 20 °C and MB-sur > 60% were observed. At the subsurface, there was a predominance of tB-20 < 40 °C, MB-20 > 60%, and pH > 9, which are indications of low bedding composting activity.
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