Mineral Changes Research Articles

Modulating Vapor Pressure Deficit in the Plant Micro-Environment May Enhance the Bioactive Value of Lettuce

Growing demand for horticultural products of accentuated sensory, nutritional, and functional quality traits has been driven by the turn observed in affluent societies toward a healthy and sustainable lifestyle relying principally on plant-based food. Growing plants under protected cultivation facilitates more precise and efficient modulation of the plant microenvironment, which is essential for improving vegetable quality. Among the environmental parameters that have been researched for optimization over the past, air relative humidity has always been in the background and it is still unclear if and how it can be modulated to improve plants’ quality. In this respect, two differentially pigmented (green and red) Salanova® cultivars (Lactuca sativa L. var. capitata) were grown under two different Vapor Pressure Deficits (VPDs; 0.69 and 1.76 kPa) in a controlled environment chamber in order to appraise possible changes in mineral and phytochemical composition and in antioxidant capacity. Growth and morpho-physiological parameters were also analyzed to better understand lettuce development and acclimation mechanisms under these two VPD regimes. Results showed that even though Salanova plants grown at low VPD (0.69 kPa) increased their biomass, area, number of leaves and enhanced Fv/Fm ratio, plants at high VPD increased the levels of phytochemicals, especially in the red cultivar. Based on these results, we have discussed the role of high VPD facilitated by controlled environment agriculture as a mild stress aimed to enhance the quality of leafy greens.

Bone material properties and response to teriparatide in osteoporosis due to WNT1 and PLS3 mutations.

Patients with osteoporosis-associated WNT1 or PLS3 mutations have unique bone histomorphometric features and osteocyte-specific hormone expression patterns. To investigate the effects of WNT1 and PLS3 mutations on bone material properties. Transiliac bone biopsies were evaluated by quantitative backscattered electron imaging, immunohistochemistry, and bone histomorphometry. Ambulatory patients. Three pediatric and eight adult patients with WNT1 or PLS3 mutations. Bone mineralization density distribution and osteocyte protein expression was evaluated in 11 patients and repeated in six patients who underwent repeat biopsy after 24months of teriparatide treatment. Bone mineralization density distribution and protein expression. Children with WNT1 or PLS3 mutations had heterogeneous bone matrix mineralization, consistent with bone modeling during growth. Bone matrix mineralization was homogenous in adults and increased throughout the age spectrum. Teriparatide had very little effect on matrix mineralization or bone formation in patients with WNT1 or PLS3 mutations. However, teriparatide decreased trabecular osteocyte lacunae size and increased trabecular bone FGF23 expression. The contrast between preserved bone formation with heterogeneous mineralization in children and low bone turnover with homogenous bone mineral content in adults suggests that WNT1 and PLS3 have differential effects on bone modeling and remodeling. The lack of change in matrix mineralization in response to teriparatide, despite clear changes in osteocyte lacunae size and protein expression, suggests that altered WNT1 and PLS3 expression may interfere with coupling of osteocyte, osteoblast, and osteoclast function. Further studies are warranted to determine the mechanism of these changes.

Effect of storage temperature and time on the fatty acids and nutritional quality of the commercial mussel (Mytilus galloprovincialis).

The effect of storage time (5, 10 and 15days) and temperature (- 20°C and + 4°C) on the biochemical composition of the Tunisian mussel (Mytilus galloprovincialis) was evaluated by investigating changes in proximate composition, fatty acids, minerals and nutritional quality indices. Lipid and protein degradations were also evaluated through several markers of oxidative damage. Results showed a significant decrease in the biochemical compounds in mussel tissues after both refrigeration and freezing processes (p < 0.01). As regards the fatty acid composition, saturated fatty acids increased significantly after both storage processes. However, polyunsaturated and monounsaturated decreased, especially after 10 and 15days of storage. The reduction of nutritional quality and mineral contents were detected after both storage processes. Markers of oxidative damage varied remarkably between fresh and stored tissues, revealing that both processes greatly influenced the nutritional quality of mussels. Overall, it is well recommended to consume fresh and stored mussels for no more than 5days in the refrigerator (+ 4°C) in order to preserve the better quality of this product and provide more benefits for human health.

Hypocalcemia and bone mineral changes in hemodialysis patients with low bone mass treated with denosumab: a 2-year observational study.

Increases in bone mineral density (BMD) following a single dose of denosumab and increased incidence of denosumab-associated acute hypocalcemia (DAAH) have been reported in chronic kidney disease patients. Little is known about clinical risk factors related to DAAH and the long-term effect of denosumab on BMD in hemodialysis patients. An observational noncontrolled study involving 47 hemodialysis patients was conducted to determine the independent risk factors related to percentage changes in serum calcium (Ca) levels associated with denosumab using multivariate regression analysis. Optimal predictive markers for DAAH were explored by receiver operating characteristic analysis. Percentage changes of BMD at the lumbar spine (LS) and femoral neck (FN) at 24 months were investigated. The incidence of DAAH [serum corrected Ca (cCa) ≤8 mg/dL] following denosumab was 25.5%. Multivariate regression analysis showed that baseline bone alkaline phosphatase was independently related to percentage changes in cCa levels (β = -0.407, P = 0.008). Tartrate-resistant acid phosphatase-5b was found to be the most accurate marker to predict DAAH, with an area under the curve of 0.750 (95% confidence interval 0.546-0.954; P = 0.02), and the optimal cut-off level was 670 mU/mL with sensitivity: 0.727 and specificity: 0.733. BMD significantly increased by 5.9 ± 1.7% (P = 0.01) at LS and 4.2 ± 1.5% (P = 0.04) at FN at 24 months. In hemodialysis patients, high bone turnover was an independent risk factor for the Ca declines induced by denosumab. Denosumab significantly increased BMD at LS and FN at 24 months.

Investigation of germinated crops elemental composition

The introduction of the crops germination stage allows increasing their nutritional value by increasing the amount of minerals, vitamins and amino acids, which are easily digested and have a beneficial effect on a human body. At the same time, heavy metals located on the surface of grains pose a danger to human health. When the grains swell, the water treated in various ways (magnetic, ultrasonic, etc.) is used. However, there is not enough information about changes in minerals and the toxic elements content during germination of flax seeds and buckwheat grains processed with physical methods. Therefore, in the work, we investigated the change in mineral substances and toxic elements during germination of flax seeds with the application of magnetized water and buckwheat grains - with ultrasonic treatment of tap water using mass spectrometry and atomic emission spectrometry with inductively coupled plasma. It was found out that the germinated flax seeds and buckwheat grains were characterized by different mineral contents and fewer toxic elements. The content of calcium, potassium, magnesium, phosphorus, selenium, copper, zinc increased in crops in the process of germination.

Functional response of an Austrian forest soil to N addition

Elevated atmospheric reactive nitrogen (NR) deposition is considered one of the key components of human induced global change, threatening biodiversity and possibly altering carbon sequestration, one of the forest’s key ecosystem services. Carbon sequestration is the net result of plant production and of soil organic matter (SOM) decomposition. Ignoring the impact of N deposition on plant growth, decomposition or any major physical, biological or anthropogenic process that alters the rate of conversion of soil organic matter to atmospheric CO2 (decomposition) will have profound implications for the global C budget and consequently climate change. Soil nitrogen cycling is predicted to change as a result of increased atmospheric N deposition and mineralization due to temperature increases. However, experimental results on the effects of increased N input on SOM decomposition in the field are inconsistent, reporting positive, negative and neutral responses of SOM to N input. We set out to test the impacts of elevated reactive nitrogen NR addition, specifically on the soil processes in the field, independently of forest production effects. Using a suite of conventional, natural abundance and isotope pool dilution methods in situ, we traced C and N transformations of soil microbial and gaseous pools and monitored concomitant changes in gross mineralization and nitrification rates, as well as enzymatic activity. Over a number of growing seasons in a spruce dominated Austrian forest we found evidence to suggest N addition significantly reduces gross N mineralization rates and enzyme activity, in-line with an emerging consensus that N deposition reduces soil fungal abundance and activity, ultimately resulting in greater stocks of soil organic carbon. Simulated elevated nitrogen deposition decelerated SOM decomposition and consequently increased soil carbon storage, an N input effect on soil processes independent of the effect of N on tree growth and forest production.

Mineral chemistry and deformation in a temperature gradient in the Sierras Pampeanas of Córdoba (Argentina): The Chicamtoltina Tonalite–Trondhjemite Orthogneiss

On the eastern margin of the Sierra Chica, in a gneissic host rocks metamorphosed under medium to high amphibolite facies (‘Sil-in’ isograd) during the Neoproterozoic–Cambrian M2-D2 event, a body of tonalitic-trondhjemitic composition was discordantly emplaced, cutting the S2 metamorphic foliation and the ‘Sil-in’ isograd. A strong deformation, with along the temperature gradient of the host rocks, transformed the igneous rocks into an orthogneiss during a M3-D3 event. Based on textural, microstructural and mineral chemistry changes along the mentioned metamorphic transition and age determination, the orthogneissification process is related to the deformational and thermal history in the Sierras Pampeanas of Córdoba. The M3-D3 event would have reworked the S2 foliation, generating an S3 foliation associated with folding and boudinage in the gneissic host rocks, forming a major intrafoliar fold in the tonalitic-trondhjemitic body, with its flanks on both sides of the ‘Sil-in’ isograd. The M3-D3 event is recorded in the textural and mineral chemistry variations, following a medium-high temperature gradient during deformation, from the southeast to the northwest of the body. In that direction, the ‘core and mantle’ texture in plagioclase increased the proportion of the recrystallized mantle, which was also enriched in anorthite content. Quartz textures evolved from polycrystalline ribbons, with internal deformation bands, to dismembered ones, with internal chessboard pattern. Recrystallization of the entire plagioclase-quartz aggregate ended in an interlobate to amoeboid texture, implying high-temperature conditions (~650-750 °C) along the mentioned temperature gradient during the M3-D3 event. Regarding micas, the primary biotite progressively increased in Mg and decreased in Fe towards the northwest, without appreciable textural changes. Concomitantly, the primary Ti-rich ferrimuscovite increases its content in Mg and becomes poor in Ti, at the same time that it developed symplectitic quartz-plagioclase intergrowths. During a final D4 deformational event, also under high ductility conditions, asymmetric intrafolial folds (drag folds, with geometrical S4 axial planes) were developed, associated with imbrication and folding of boudins within the S3 (// S2) foliation. The D2, D3, and D4 deformation events are part of a continuum (progressive deformation) in a combined simple shear and flattening regimen (transcompression = convergent oblique shear). The contrasting rheology between the stiffer Chicamtoltina igneous body and its gneissic host rocks explain the different behavior during high ductility deformation. Internally, this small igneous body, with plagioclase as stress-supporting mineral framework (plagioclase-quartz ratio 2:1), mirrored the rheological behavior of the middle to lower crust deformation. A concordia age of 535.81 ± 0.79 Ma (U–Pb LA-ICP-MS on zircon) obtained for the Chicamtoltina orthogneiss is interpreted as the crystallization age of the tonalitic-trondhjemitic protolith (igneous event Ig1). By correlation with the tonalitic orthogneisses from the Sierra Chica and Sierra Norte of Córdoba, this protholith is linked to the Pampean magmatic arc, with an age range of 541–515 Ma and a peak of magmatic activity at 530–535 Ma.

Effects of feeding bulls dried corn distiller’s grains plus solubles or CaSO4 on mineral and metabolite concentrations in serum and seminal plasma

Yearling Angus bulls (n = 36) were assigned one of three diets: 1) 60 % concentrate as corn (CON, 0.2 % S, 13.4 % CP; n = 12); 2) 60 % dried corn distiller’s grains plus solubles (60DDGS 0.5 % S, 22.0 % CP; n = 12); 3) CON diet + equivalent sulfur of 60DDGS as CaSO4 (SULF, 0.5 % S, 13.9 % CP; n = 12) to evaluate effects of feeding 60 % DDGS or sulfur as CaSO4 on mineral and metabolite concentrations in serum and seminal plasma. Treatment × day interactions (P < 0.03) were observed for serum Cu, Se, and Mo. For Cu at d 112, lesser (P < 0.01) concentrations were observed in bulls fed the 60DDGS compared to SULF and CON diets. There were greater (P < 0.01) concentrations of Se at d 112 in bulls fed 60DDGS than CON and SULF diets. Concentrations of Mo were greater at d 56 and 112 (P < 0.01) in bulls fed CON compared to SULF and 60DDGS diets. In seminal plasma, there were treatment × day interactions (P < 0.02) for Cu and Mo. For Cu, at d 112, there was a lesser (P < 0.01) concentration in the bulls fed SULF compared to CON and 60DDGS diets. For Mo, there was a greater (P < 0.01) concentration in bulls fed the CON than 60DDGS and SULF diets at d 56 and 112. Changes in mineral and metabolite concentrations may have effects on bull reproductive performance when there is a relatively greater dietary sulfur content.

Effect of salt stress on the growth, mineral contents, and metabolite profiles of spinach.

Increased soil salt concentration decreases productivity and changes the physiological and chemical properties of plants. Various omics technologies have been used to understand the salt response in plants but overall changes in the metabolite profiles of spinach (Spinacia oleracea L.) under salt stress have not been studied. In this article, therefore, the changes in mineral and metabolite profiles of spinach plants cultivated with different NaCl concentrations of 0-200 mmol L-1 in the irrigation water were analyzed to investigate the effect of salt stress on nutritional quality. Increasing NaCl concentration decreased plant growth due to mineral imbalance. The amounts of minerals (K+ , Ca2+ , and Fe2+ ) were reduced with increasing NaCl concentration, resulting in altered ratios of Na+ :K+ and Na+ :Ca2+ . The change in the mineral ratios due to NaCl irrigation led to a decrease in the height and an increase in the weight of spinach. Moreover, the profiles of 32 metabolites, including flavonoids, amino acids, acidic compounds, sugars, and lipid-related compounds, were altered by NaCl irrigation; most of them showed decreased levels. In particular, at 200 mmol L-1 NaCl, the levels of sucrose, glutamic acid, hexose sugars, and acidic compounds significantly decreased upon NaCl irrigation. Based on these metabolites, a salt-stress-related spinach metabolomic pathway was proposed. Sodium chloride irrigation increased mineral imbalance, resulting in decreased plant growth, and the levels of most metabolites involved in energy production, sensory quality, and health benefits decreased with NaCl irrigation. The results suggest that NaCl irrigation negatively affects the nutritional quality of spinach. © 2020 Society of Chemical Industry.

Priming, stabilization and temperature sensitivity of native SOC is controlled by microbial responses and physicochemical properties of biochar

Biochars generally result in short-term positive priming of native soil organic carbon (SOC), but longer-term carbon (C) stabilization, and these effects can be altered by global warming. However, uncertainty remains about the mechanisms associated with these priming effects, temperature sensitivity of native SOC, and microbial responses to biochars of differing properties. To address these knowledge gaps, rice straw biochars (produced at 300 and 800 °C at 2% w/w application rate), and their labile (water extracted) fraction and recalcitrant (chemically oxidized) fraction (obtained from the equivalent weight of biochar) were incubated in a C4 dominated soil at 15, 25, and 35 °C. Our results showed that 300 °C biochar and its recalcitrant fraction resulted in an increased SOC mineralization due to positive priming across the incubation thermosequence. This was likely linked to an observed increase in the abundance of K-strategists (fungi and Actinobacteria). The biochar produced at 800 °C and its recalcitrant fraction resulted in the stabilization of native SOC (i.e., negative priming) at all temperatures, likely due to the adsorptive protection of native SOC by the large surface area. The water extractable C from both biochars generally induced SOC stabilization across the thermosequence, which could be attributed to microbial shifts to r-strategists preferentially utilizing labile C components in biochar. Both biochars increased SOC stabilization with warming from 15 to 25 °C, supporting the role of biochar application in soil C sequestration in cooler regions. The lower SOC stabilization by biochars with temperature increases from 25 to 35 °C was correlated with the biochar-induced increases in fungal growth (K-strategist) under warming. The low-temperature biochar increased the abundance of aromatic C decomposers and concomitantly lowered the Q10 and activation energy (Ea) of native SOC. The findings from this study highlight that the low- and high-temperature biochars can result in various changes in native SOC mineralization, as well as temperature sensitivity, mainly by microbial population alterations and physicochemical interactions.

Quality attributes of convective hot air dried spine gourd (Momordica dioica Roxb. Ex Willd) slices

In the present study, spine gourd slices were dried in a convective dryer at 40, 50, 60 and 70 °C temperature. The change in quality of spine guard was determined by analyzing the change in proximate, minerals, functional group, chlorophyll, ascorbic acid, and antioxidant characteristics. Increase in drying temperature changed the protein (4.62–12.88 g/100 g), fiber (3.14–3.53 g/100 g), total phenolic (14.85–14.99 mg gallic acid equivalent/g) and total flavonoid (30.1–64.8 mg quercetin equivalent/100 g) content while reduction occurred in fat (4.02–3.07 g/100 g), carbohydrate (76.13–55.22 g/100 g), chlorophyll (0.34–0.100 mg/g), ascorbic acid (29.94–4.50 mg/100 g) and antioxidant activity (96.58–85.06%). Mineral content of fresh SG differed significantly with dried samples (p < 0.05), while variable effects were associated with the change in drying temperatures. Changes in functional groups were analyzed by Fourier transform infrared spectrophotometer. The observed parameters were optimized using principal component analysis. The sample dried at 40 °C was superior in quality whereas higher protein and antioxidants were found at 70 °C.

Effects of Raloxifene and tibial loading on bone mass and mechanics in male and female mice

ABSTRACT Purpose: Raloxifene (RAL) is a selective estrogen receptor modulator (SERM) that has previously been shown to cause acellular benefits to bone tissue. Due to these improvements, RAL was combined with targeted tibial loading to assess if RAL treatment during periods of active bone formation would allow for further mechanical enhancements. Methods: Structural, mechanical, and microstructural effects were assessed in bone from C57BL/6 mice that were treated with RAL (0.5 mg/kg), tibial loading, or both for 6 weeks, beginning at 10 weeks of age. Results: Ex vivo microcomputed tomography (CT) images indicated RAL and loading work together to improve bone mass and architecture, especially within the cancellous region of males. Increases in cancellous bone volume fraction were heavily driven by increases in trabecular thickness, though there were some effects on trabecular spacing and number. In the cortical regions, RAL and loading both increased cross-sectional area, cortical area, and cortical thickness. Whole-bone mechanical testing primarily indicated the effects of loading. Further characterization through Raman spectroscopy and nanoindentation showed load-based changes in mineralization and micromechanics, while both loading and RAL caused changes in the secondary collagen structure. In contrast to males, in females, there were large load-based effects in the cancellous and cortical regions, resulting in increased whole-bone mechanical properties. RAL had less of an effect on cancellous and cortical architecture, though some effects were still present. Conclusion: RAL and loading work together to impact bone architecture and mechanical integrity, leading to greater improvements than either treatment individually.

Artificial Caries Lesion Characteristics after Secondary Demineralization with Theobromine-Containing Protocol.

Developing artificial caries lesions with varying characteristics is needed to adequately study caries process in vitro. The objective of this study was to investigate artificial caries lesion characteristics after secondary demineralization protocol containing theobromine and fluoride. Sixty bovine enamel slabs (4 × 3 mm) were demineralized using a Carbopol-containing protocol for 6 days. A baseline area (2 × 3 mm) was protected with acid-resistant nail varnish, after which specimens were exposed for 24 h to a secondary demineralization protocol containing acetic acid plus one of four fluoride/theobromine combinations (n = 15): theobromine (50 or 200 ppm) and fluoride (0 or 1 ppm). Specimens were sectioned and analyzed using transverse microradiography for changes in mineral content, lesion depth, and surface layer mineralization. Data was analyzed using paired t-test and analysis of variance followed by Bonferroni test at 0.05 significance level. After secondary demineralization, fluoride-containing groups had significantly deeper lesions (p = 0.002 and 0.014) compared to the group with 0 ppm fluoride and 50 ppm theobromine. Mineral content and lesion depth were significantly different compared to baseline for all groups. Theobromine did not show an added effect on mineral uptake. Theobromine-containing groups exhibited particularly deep lesions with a more uniform mineral profile in the presence of fluoride.

Effects of Water Immersion and Acidification on Nano-Pores in Tight Sandstones-A Case Study of the Gaotaizi Reservoir, Songliao Basin.

Hydraulic fracturing and acidification are among the most commonly used methods for stimulating the tight oil reservoirs and improving oil recovery. Therefore, examining the effects of water immersion and acidification on tight oil reservoirs is important for oilfield development plans. Core flooding testing, which analyzes the influence of core permeability variations before and after acid injection on the reservoir quality, is the conventional research method; however, it is difficult to observe the changes in minerals and pores caused by acidulation and water immersion in situ. In this study, we conduct field-emission scanning electron microscopy (FE-SEM), MAPS, the quantitative evaluation of minerals through scanning electronic microscopy (QEM-SCAN), and describe the types of pores in tight sandstone. Further, the effects of water immersion and acidification on pores in tight sandstone were studied. The results indicate that: (1) intergranular pores, intragranular dissolution pores, clay mineral intercrystalline pores, and micro-cracks were developed in the Gaotaizi tight sandstone in Songliao Basin, with the intergranular pores observed to be dominant; (2) the hydration of clay minerals induced by water injection caused plugging of pores at the nanometer- micrometer scale, and plane porosity is slightly reduced (˜0.86%); (3) acidification resulted in the dissolution of carbonate minerals, increasing the porosity of the reservoir, therefore, the increase in porosity is influenced by the carbonate mineral content. We recommend that future studies should investigate the content, type, and distribution of carbonate minerals in the operation area. During the process of reservoir stimulation, such as acidification and CO₂ injection- and-production, the influence of carbonate minerals dissolution on oil production should be considered.

Late Cenozoic tectonic process in the NE Pamir Salient: Evidences from the sedimentary record and heavy mineral changes

帕米尔弧形构造带东北缘晚新生代沉积特征的研究对于理解帕米尔构造带弧形扩展机制具有重要意义。本文通过对帕米尔弧形构造带东北缘的晚新生代沉积地层的沉积特征对比研究和重矿物采样与组份分析，建立了帕米尔弧形构造带东北缘地区的晚新生代沉积联合柱状对比图和重矿物组份变化曲线。研究结果表明，晚新生代沉积与重矿物变化主要记录了帕米尔弧形构造带东北缘的两期构造活动。第一期构造活动发生在安居安组沉积时期，帕米尔弧形构造带东北缘的和什拉甫剖面、英科1井表现为粗碎屑沉积和对应的不稳定重矿物爆发，而南部的甫沙2井中则并未观察到，这一事件可能反映了喀什-叶城走滑系统在和什拉甫剖面附近的中新世构造启动。第二期构造活动发生在阿图什组沉积期间，帕米尔弧形构造带东北缘全区域出现了一套粗碎屑沉积和对应的不稳定重矿物爆发，反映了帕米尔弧形构造带东北缘在上新世以来大规模向北楔入塔里木盆地内部的构造过程。

Functionalization of clay surface for the removal of uranium from water

A modification method of clay mineral surface was developed to improve its adsorption capacity of uranium. Uranium is a radionuclide with high toxicity and extremely long half-life, which can pollute the environment and endanger human health. This study proposes a new method of activation of clay mineral surface with phosphoric acid for rapid adsorption of uranium from aqueous solution. Compared with other modification methods, this method has the advantages of availability of raw materials, simple operation and good adsorption effects. It provides a cost-effective material to capture uranium ions from water. The essences of this new development are as following:• Activation and changes of clay minerals’ surface functionalities with the treatment of phosphoric acid• Controlled modifications of the surface properties of the clay towards the enhancement of U adsorption capacity• Rapid removal of uranium from water

ЭФФЕКТИВНОСТЬ ВОЗДЕЛЫВАНИЯ ЧЕЧЕВИЦЫ НА ЧЕРНОЗЕМЕ ОБЫКНОВЕННОМ В ЗАВИСИМОСТИ ОТ НОРМЫ ВЫСЕВА И ДОЗ МИНЕРАЛЬНЫХ УДОБРЕНИЙ

Purpose: to reveal the efficiency of the Donskaya variety lentils cultivation on ordinary chernozem at different seeding rates and doses of mineral fertilizers. Materials and methods. The research was carried out in Aksai district Rostov region on the experimental field of the Federal State Budget Scientific Institution “Federal Rostov Agricultural Research Centre” (FSBSI FRARC). The objects of research are the yield and protein content in lentil grain, depending on the seeding rate and the mineral fertilizers dose. The experiments setting, recording and mathematical processing of the data obtained were carried out according to B. A. Dospekhov. Results. It has been found that the yield of Donskaya lentils is significantly influenced by both mineral fertilizers and changes in sowing rates. The maximum yield was obtained at sowing seeds at a rate of 2.2 million pcs/ha, while the plant stand and the feeding area were optimal for development. The maximum yield increase was obtained in the N20P40 variant, amounting to 0.55 t/ha. As the seeding rate increases, the protein content in the lentil grain decreases. The application of mineral fertilizers leads to a significant increase in the protein content at all studied seeding rates. The combined use of nitrogen and phosphorus fertilizers leads to an increase in protein content compared to the application of only phosphorus fertilizers. Calculation of the agrochemical efficiency of the applied fertilizers showed that the highest payback of lentils at rates of 2.2 and 2.8 million pcs/ha was obtained with the introduction of 20 kg of active agent of phosphorus, amounting to 1.5 and 11.5 kg/kg active agent respectively. When sowing at a rate of 1.6 million pcs/ha, the maximum payback was obtained with the introduction of 40 kg active agent of phosphorus. Conclusion. It was found that it is economically efficient to cultivate lentils when sowing seeds at a rate of 2.2 million pcs/ha with the introduction of 20 kg of active agent of nitrogen and 40 kg active agent of phosphorus, this allows you to get the maximum net income (44.3 thousand rubles/ha) and payback of direct costs (3.1 rubles) with the lowest cost of grain produced (9.6 thousand rubles/ton).

Clay Minerals Change the Toxic Effect of Cadmium on the Activities of Leucine Aminopeptidase

Soil leucine aminopeptidase (LAP) is a hydrolytic enzyme involved in the acquisition of nitrogen by microorganisms. In contaminated soils, LAP activity is affected not only by the type and concentration of heavy metals but also by the form of enzyme. Here, we investigated the degree and mechanism of cadmium (Cd) inhibition of soil LAP and purified LAP. We also examined the effect of montmorillonite and kaolinite on LAP and LAP contaminated with Cd. The results showed that Cd inhibition of LAP activity increased with increasing Cd concentration and that Cd exerted noncompetitive inhibition of LAP. The addition of clay minerals decreases LAP activity and the maximum reaction rate ([Formula: see text]), regardless of the presence of Cd. Montmorillonite decreases the affinity of LAP to the substrate ([Formula: see text]), while kaolinite increases the affinity of LAP to the substrate. The clay mineral-immobilized LAP showed an increase in resistance to Cd contamination compared with the free LAP. The results obtained in this study may aid in understanding the toxic effects of heavy metals on soil enzymes.

Long‐term rice–crayfish farming aggravates soil gleying and induced changes of soil iron morphology

AbstractThe integrated rice–crayfish (RC) farming has become popular in rice‐growing areas in China. In order to raise crayfish in paddy, the RC system requires large amounts of feed and flooding of fields, and changes in the use and management of paddy may have an impact on soil properties. This study investigated the effects of feed placement and long‐term flooding on soil profile structure, organic carbon, total nitrogen, total phosphorus, total potassium, redox status and iron oxides during RC farming. A series of paddy soil profiles from rice–crayfish paddies were sampled. Samples from adjacent paddies with rice monoculture (RM) were used for comparison. Soil samples from each paddy field were collected vertically every 20 cm from surface to a depth of 1 m. Our research indicated that the thicknesses of the gley horizons and concentrations of total nitrogen, total phosphorus, total potassium, soil organic carbon, total amount of reductive mater, active reducing matter, ferrous iron, divalent manganese, oxalate‐extractable iron (Feo), and pyrophosphate‐extractable iron (Fep) increased with the duration of RC farming. Conversely, Eh, and dithionite‐extractable iron (Fed) content significantly decreased with time. In comparison with RM, the longer RC system lasts, the more severe gleying of the surface soil occurs, and the depth of gley extends downwards in the soil profile. Particularly thickened gleization layer, high content of organic nutrients, presence of reducing substances, low Eh value, and changes of soil iron minerals which affect soil fertility can predictably worse the function of the rice paddy environment and ecosystems.

Plant intraspecific competition and growth stage alter carbon and nitrogen mineralization in the rhizosphere.

Plant roots interact with rhizosphere microorganisms to accelerate soil organic matter (SOM) mineralization for nutrient acquisition. Root-mediated changes in SOM mineralization largely depend on root-derived carbon (root-C) input and soil nutrient status. Hence, intraspecific competition over plant development and spatiotemporal variability in the root-C input and nutrients uptake may modify SOM mineralization. To investigate the effect of intraspecific competition on SOM mineralization at three growth stages (heading, flowering, and ripening), we grew maize (C4 plant) under three planting densities on a C3 soil and determined in situ soil C- and N-mineralization by 13 C-natural abundance and 15 N-pool dilution approaches. From heading to ripening, soil C- and N-mineralization rates exhibit similar unimodal trends and were tightly coupled. The C-to-N-mineralization ratio (0.6 to 2.6) increased with N availability, indicating that an increase in N-mineralization with N depletion was driven by microorganisms mining N-rich SOM. With the intraspecific competition, plants increased specific root lengths as an efficient strategy to compete for resources. Root morphologic traits rather than root biomass per se were positively related to C- and N-mineralization. Overall, plant phenology and intraspecific competition controlled the intensity and mechanisms of soil C- and N- mineralization by the adaptation of root traits and nutrient mining.