Abstract A methodology combining physical experiments with simulation was employed to acquire contact parameters of sandy soil precisely for planting tiger nuts in the desert area of Xinjiang. The ...stacking angle under different parameter combinations was applied as a response value. Through the Plackett–Burman test, several factors that have a significant influence were determined. The steepest ascent test was conducted to establish the finest scope of values for these parameters. The stacking angle was considered the response variable, and non-linear tools were used to optimize these parameters for simulation. The findings showed that applying response surface methodology (RSM) resulted in a relative error of 1.24%. In the case of BP-GA, the relative error compared to the physical test value was 0.34%, while for BP, it was 2.18%. After optimization using Wavelet Neural Network (WNN), the relative error was reduced to only 0.15%. Results suggest that WNN outperforms the RSM model, and the sandy soil model and parameters generated using WNN can be effectively utilized for discrete element simulation research.
•Over the four years crop yields were never increased by biochar.•In the first months biochar caused manganese deficiency in maize.•Biochar increased nitrate retention in the topsoil 0–15cm where it ...was incorporated.•Biochar could not alleviate N uptake limitation under drought conditions.•The same soil and biochar produced different results in a greenhouse compared to the field study.
The use of biochar (BC) is discussed as a strategy to sequester carbon in soils, to reduce GHG emissions and improve soil fertility. However, the responses of crop yields to biochar amendments in agricultural ecosystems, specifically under temperate field conditions, are still uncertain. Furthermore, results obtained under field conditions are often differing from laboratory studies. Therefore, the establishment of long-term studies under field conditions is mandatory to provide the base for recommendations. We carried out a two-factorial split-plot field experiment over four years (2012–2015, still in progress) to compare the effects of BC on crop yields, mineral nitrogen (NO3− and NH4+) dynamics, soil moisture and initial soil CO2 efflux. A temperate sandy soil was amended with BC (0, 15 and 30Mgha−1) with the second factor being watering regime (irrigated or rainfed). The soil CO2 efflux was increased only for a short time following BC amendments. Freshly incorporated BC (30Mgha−1) initially induced manganese (Mn) deficiency at the vegetative stage of the first crop maize (Zea maize L.). Biochar amendments significantly reduced NO3− leaching, as indicated by greater NO3− stocks in the topsoil and reduced stocks in the subsoil (0–15, BC amendment zone and 60–90cm respectively). In BC treatments a higher soil moisture and higher NO3− amount was observed, however, this did not translate into higher yields. Rather, grain yields of maize (year I) and summer barley (Hordeum vulgare L., year III, no nitrogen (N) fertilization) were significantly reduced (1–11 and 5–26% respectively) due to N deficiency with BC amendment or (non-alleviated) drought stress. A prolonged drought spell in 2015 (year IV) drastically reduced the grain yield of maize (5 and 0.7Mgha−1) and N uptake (96 and 11kgha−1) in the irrigated and rainfed treatments respectively, without any alleviating effects of biochar amendment. We conclude that application of large amounts of pure, non-nutrient-loaded biochar to temperate sandy soils may provide environmental benefits, such as carbon sequestration and reduction of nitrate leaching, but without an economic incentive for implementing biochar use, at least for the initial few years of application.
Mercuric ion (Hg2+) is one of the most toxic and serious environment polluting heavy metal ions, which can be accumulated in human body through food chains and drinking water, and causes serious ...damage to human organs. Therefore, development of the efficient and sensitive method for detection of Hg2+ is very necessary. In this study, the high surface sensitivity and fingerprint information about the chemical structures based on surface‐enhanced Raman scattering (SERS) for sensing applications are taken advantage of. Au triangular nanoarrays/n‐layer graphene/Au nanoparticles sandwich structure with large‐area uniform subnanometer gaps are fabricated and used to detect Hg2+ in water via thymine–Hg2+–thymine coordination; the detection limit of Hg2+ is as low as 8.3 × 10−9m. Moreover, this SERS substrate is used to detect the Hg2+‐contaminated sandy soil and shows excellent performance. This study indicates the sandwich structure has a great potential in detection of toxic metal ions and environmental pollutants.
Ultrasensitive surface‐enhanced Raman scattering (SERS) substrate with large‐area uniform subnanometer “hot spots” is used to detect mercuric ion in water and sandy soil; the detection limit is as low as 8.3 × 10−9m. The uniformity of the SERS substrate is proved by Raman mapping, and the physical mechanism of SERS enhancements is supported by the finite difference time domain method.
The paper presents a method of application of an ANN (Artificial Neural Network) to predict the permeability coefficient k in sandy soils: FSa, MSa, CSa. To develop an ANN the results of permeability ...coefficients from pumping and consolidation tests were applied. The proposed ANN with an architecture 6-8-1 predicts the value of permeability coefficient k based on the following parameters: soil type, relative density Isub.D, void ratio e and effective soil diameter dsub.10. The mean relative error and single maximum value of the relative error for the proposed ANN are following: Mean RE = ±4%, Max RE = 7.59%. The use of the ANN to predict the soil permeability coefficient allows the reduction of the costs and time needed to conduct laboratory or field tests to determine this parameter.
Penstemon x jonesii is described as having flowers with the colors of "Tyrian rose," "amaranth purple," or "red-purple to maroon." It has been recorded only in localized areas of southwestern Utah ...and just over the border of Arizona, where both putative parents commonly occur in sandy soils. Penstemon x jonesii has been reported and widely accepted as a natural hybrid of P. laevis x P. eatonii, though no research has been conducted to verify this assumption. We examined claims of its hybrid origin by making interspecific reciprocal first-generation hybrid plants from the 2 suspected parental species (P. eatonii and P. laevis) as well as by making second-generation hybrids through backcrossing to both parental species. Using 9 Penstemon simple sequence repeat (SSR), or microsatellite, markers, we examined the allelic variation among natural populations of P x jonesii, P. eatonii, and P. laevis in southwestern Utah. These SSR data, in conjunction with our controlled crosses, support claims that P. x jonesii likely descends from hybridization events between P. eatonii and P. laevis. Flower color of the typical P x jonesii reported in the literature and found in herbarium samples does not resemble the flower color of F.sub.1 P. eatonii x P. laevis hybrids from our controlled crosses. However, in subsequent controlled backcrossing of the F.sub.1 hybrids to P. eatonii, we found blossom morphotypes and corolla colors matching previous descriptions of P. x jonesii. We also observed many hybrids with lighter corolla colors, such as light pinks, pinkish yellows, and lavender, which are not recorded in the literature or found in herbarium specimens. Field surveys for natural color variation in P. x jonesii populations also revealed greater flower color variation than previously reported, which should be considered as part of this hybrid taxa as well, though the predominant floral colors of P. x jonesii are "Tyrian rose," "amaranth purple," and "red-purple to maroon," which suggests some selective bias. We suggest that pollinator preference for dark red to purple blooms may be responsible for this phenomenon. La planta Penstemon x jonesii, caracterizada por sus flores color "rosa de Tyria", "violeta amaranto" o "rojo avioletado a rojo oscuro". Ha sido registrada, unicamente, en determinadas areas del suroeste de Utah y en suelos arenosos de la frontera de Arizona, donde es posible encontrar a sus presuntas especies parentales. Penstemon x jonesii ha sido documentada y ampliamente aceptada como un hibrido natural de P. laevis x P. eatonii. Sin embargo, no se han llevado a cabo investigaciones que verifiquen tal aseveracion. Con el fin de, confirmar su origen hibrido cultivamos plantas hibridas reciprocas interespecificas de primera generacion de las dos supuestas especies parentales (P. eatonii y P. laevis), e hibridos de segunda generacion, a traves del retrocruzamiento de ambas especies parentales. Utilizando nueve marcadores de secuencia repetida simple (SSR, por sus siglas en ingles) o microsatelites, examinamos la variacion alelica entre las poblaciones naturales de P x jonesii, P. eatonii y P. laevis al suroeste de Utah. Estos datos de SSRs, junto con nuestros resultados de cruces controlados, respaldan las aseveraciones de que P x jonesii probablemente desciende de eventos de hibridacion entre P. eatonii y P. laevis. El tipico P x jonesii que encontramos en la literatura y en muestras de herbario no se parece al color de la flor de los hibridos F.sub.1 P. eatonii x P. laevis de nuestros cruces control. Sin embargo, en los subsecuentes retrocruzamientos controlados de los hibridos F.sub.1 a P. eatonii, hallamos morfotipos florales y colores de corola coincidentes con las descripciones previas de P x jonesii. Tambien, observamos muchos hibridos con corolas de colores mas palidos, tales como rosa claro, amarillo rosado y lavanda, que no estan documentados en la literatura o en ejemplares de herbario. Muestreos de campo relacionados a la variacion del color natural de las poblaciones de P x jonesii tambien, revelaron una mayor variacion respecto al color de las flores anteriormente reportadas, que deben considerarse como parte de este taxon hibrido, aunque los colores florales predominantes continuen siendo "rosa de Tyria", "violeta amaranto" y "rojo avioletado a rojo oscuro", lo cual indicaria un sesgo selectivo. Sugerimos que la preferencia de los polinizadores por las flores de color rojo oscuro a morado puede ser la responsable de este fenomeno.
Ammonia (NHsub.3) emissions affect the environment, the climate, and human health and originate mainly from agricultural sources like urea fertilizers. Such losses from urea fertilizer can be avoided ...by different application techniques like incorporation. However, the knowledge of the effect of these techniques on NHsub.3 emissions is very limited and ambiguous since incorporation can also promote nitrous oxide (Nsub.2O) emissions. Three different principles of fertilizer incorporation methods were compared in three different soils (sandy, loamy, and clayey) at two moisture levels of 70% and 30% water-holding capacity (WHC), shallow mixing at 2 cm, injection with the slit technique at 5 cm, and deep complete incorporation at 5 cm simulating plow incorporation. The laboratory study was conducted with open dynamic incubation chambers where NHsub.3 emissions were monitored with washing bottles while Nsub.2O emissions were studied with gas chromatographic (GC) measurements. The highest cumulative NHsub.3 emissions occurred at low soil moisture levels in sandy soil (34% of the N applied). A maximum reduction in emissions by 87% was achieved with slit injection and 82% with deep injection compared to standard surface application. The reduction effect was positively related to increasing clay content. Nsub.2O emissions were delayed and highest from sandy soil. Overall, all urea incorporation techniques showed great potential for mitigating NHsub.3 emissions on the clayey soil; for sandy and drier soils, only deeper or closed slot injection were consistently effective. However, connected to the surface incorporation at the higher moisture level, a relevant increase in Nsub.2O emissions compared to surface application was observed. Therefore, an increase in Nsub.2O emissions by urea incorporation may rule out specific incorporation techniques for NHsub.3 emissions reduction from field-applied urea. In agricultural practice, a lower reduction in NHsub.3 by fertilizer incorporation can be assumed in sandy soils or under dry soil conditions, as well as a more challenging technical implementation.
AIMS: Biochar (BC) and humic acid product (HAP) soil amendments may improve plant performance under water-limited conditions. Our aim was to investigate if BC and HAP amendments, alone or in ...combination, will have positive and synergistic effects. METHODS: A three-factorial fully randomized study was carried out in the greenhouse for 66 days, including the factors ‘BC’, ‘HAP’ and ‘water regime’. Maize (Zea mays var. ‘Amadeo’ DKC-3399) was grown in pots (6 kg sandy soil pot⁻¹) amended with/without BC (0, 1.5 and 3 %; w/w) and with/without HAP (0 or an equivalent of 8 kg ha⁻¹). Two water regimes, limited and frequent (H₂O ₗᵢₘᵢₜ , H₂O fᵣₑqᵤ), were applied after day 28 following seedling establishment at 60 % water holding capacity (WHC). In the H₂O ₗᵢₘᵢₜ treatment, the soil water content was allowed to drop until wilting symptoms became visible (25–30 % WHC) while in H₂O fᵣₑqᵤ the WHC was brought to 60 % of the maximum on a daily basis RESULTS: BC but not HAP, added alone or in combination with BC, significantly increased the biomass yield and the water and N use efficiency of plants at both water regimes. The BC-mediated relative increase in the yield was equal with both watering regimes, refuting initial hypotheses. BC had generally a stimulating effect on water relations and photosynthesis, it increased the relative water content and the leaf osmotic potential, decreased the stomatal resistance and stimulated the leaf gas exchange (transpiration). Both, BC and pure HAP addition, stimulated photosynthesis by increasing the electron transport rate (ETR) of photosystem II (PSII) and of the ratio between effective photochemical quantum yield to non-photochemical quenching (Y(II)/Y(NPQ), revealing reduced heat dissipation. CONCLUSIONS: Biochar use in poor sandy soils can improve plant growth by improving soil-plant water relations and photosynthesis under both H₂O fᵣₑqᵤ and H₂O ₗᵢₘᵢₜ conditions. HAP loading, however, did not improve the effect of biochar or vice versa.
The uptake pathways of nanoplastics by edible plants have recently been qualitatively investigated. There is an urgent need to accurately quantify nanoplastics accumulation in plants. Polystyrene ...(PS) particles with a diameter of 200 nm were doped with the europium chelate Eu-β-diketonate (PS-Eu), which was used to quantify PS-Eu particles uptake by wheat (Triticum aestivum) and lettuce (Lactuca sativa), grown hydroponically and in sandy soil using inductively coupled plasma mass spectrometry. PS-Eu particles accumulated mainly in the roots, while transport to the shoots was limited (for example, <3% for 5,000 μg PS particles per litre exposure). Visualization of PS-Eu particles in the roots and shoots was performed with time-gated luminescence through the time-resolved fluorescence of the Eu chelate. The presence of PS-Eu particles in the plant was further confirmed by scanning electron microscopy. Doping with lanthanide chelates provides a versatile strategy for elucidating the interactions between nanoplastics and plants.
Although interactions between plants and microbes at the plant–soil interface are known to be important for plant nutrient acquisition, relatively little is known about how root exudates contribute ...to nutrient exchange over the course of plant development. In this study, root exudates from slow‐ and fast‐growing stages of Arabidopsis thaliana plants were collected, chemically analysed and then applied to a sandy nutrient‐depleted soil. We then tracked the impacts of these exudates on soil bacterial communities, soil nutrients (ammonium, nitrate, available phosphorus and potassium) and plant growth. Both pools of exudates shifted bacterial community structure. GeoChip analyses revealed increases in the functional gene potential of both exudate‐treated soils, with similar responses observed for slow‐growing and fast‐growing plant exudate treatments. The fast‐growing stage root exudates induced higher nutrient mineralization and enhanced plant growth as compared to treatments with slow‐growing stage exudates and the control. These results suggest that plants may adjust their exudation patterns over the course of their different growth phases to help tailor microbial recruitment to meet increased nutrient demands during periods demanding faster growth.
Here, we found that the fast‐growing stage root exudates induced higher nutrients mineralization resulted in better plant growth as compared to treatments with slow‐growing stage exudates and the controls. Plants appear to recruit specific beneficial microbiomes throughout their different growth phases, thereby tailoring microbial activities to meet increased nutrient demands during fast‐growing stages.
