The objective of this study was to explore the distribution of poisonous plants and soil quality in relation to grassland degradation in the Qinghai-Tibetan Plateau (QTP) by employing poisonous ...plants characteristics including diversity index, coverage and composition and the soil properties including soil physical, chemical, and biological indicators. The degraded grasslands (DGs) had significantly increased cover and diversity values of poisonous plants compared with the non-DGs (NDGs). Grassland use types had significant effects on the composition and characteristics of poisonous plants. The NDGs had increased levels of soil nutrients and soil enzyme activities, with decreased soil pH and bulk density (BD), indicating a higher and better soil nutrient status compared with DGs. The soil texture, soil pH, and soil BD were very important in affecting the structures of poisonous plants. We concluded that grassland degradation had significant effect on poisonous plants coverage and diversity; conversely, poisonous plants also aggregated the grassland degradation, decreasing the soil fertility in the QTP.
The response trends for CO2, N2O, and CH4 greenhouse gas emissions (GHGs) and factors influencing them in greenhouse vegetable soils following different of cultivation years were revealed in this ...study. The greenhouse vegetable fields of cultivation for 1 year (CK), 5 (Y5), 10 (Y10), 15 (Y15), and 20 years (Y20) under the same management systems were selected for this study. GHGs in the experimental greenhouse vegetable soils were determined by GHGs fluxes combined with soil physical and chemical properties, enzyme activities, and other environmental factors. The results showed differential responses of the three greenhouse gases according to the cultivation years of vegetable soils. The emission fluxes and total emissions of CO2 and N2O were significantly increased (P<0.05) with increasing cultivation years compared with that of the CK, and N2O emission fluxes was more affected by cultivation years, whereas the effect of cultivation years on CH4 emission was not significant. The greenhouse gas warming potential (GWP) and emission intensity (GHGI) of greenhouse vegetable soils were significantly increased (P<0.05) with increasing cultivation years, and the contribution rate of N2O to GWP also was increased with cultivation years. Redundancy analysis (RDA) showed that soil organic carbon (SOC), NO3--N content, p-l,4-N-acetyl-glu-cosaminidase (NAG), nitrate reductase (NRA), and pH were the key factors to influence the GHGs of greenhouse vegetable soils. Therefore, long-term cultivation of greenhouse vegetables promoted the emission of CO2 and N2O by increasing the content of SOC and NO3-N in soil, improving the activities of NAG and NRA, and reducing soil pH. In conclusion, emission fluxes, total emissions, GWP, and GHGI were gradually increased with increasing cultivation years. Therefore, reasonable measures should be taken to reduce NO3-N content and increase in soil pH, which may contribute to decrease GHGs in long-term cultivation of greenhouse vegetable soils.
Introduction
Localized nitrogen (N) supply affects rice N uptake by influencing N release, and few studies have examined the effects of root zone N distribution and root growth on rice yield under ...localized N supply (LNS).
Methods
A two-year field experiment was conducted with six treatments: no N application, farmers’ fertilizer practice (FFP), and four LNS treatments, including two types of N fertilizer with urea (U) and controlled release urea (CRU) were mechanically side deep fertilized (SDF) or root zone fertilized (RZF) at 10 cm soil depth (US, UR, CRUS and CRUR treatments, respectively).
Results
Compared with FFP, the dry matter accumulation, N uptake, and yield of LNS increased by 27%, 21%, and 17%, respectively. For N fertilizer type, compared with U, the NH
4
+
-N concentration, total root surface area, volume, average diameter, and root biomass of CRU were significantly increased by 50%, 43%, 53%, and 23%, respectively, which resulted in a significant increase in yield by 12%. Regarding the N application methods, the total surface area, volume, average diameter, and root biomass of SDF were significantly increased by 32%, 24%, 10%, and 25% compared with RZF, respectively. However, the NH
4
+
-N under RZF was more stable and lasted longer, with a significant increase in NH
4
+
-N concentration of 21% compared to the SDF. Moreover, CRUR increased yield, N agronomic use efficiency, and gross return by 3.15%, 5.62%, and 2.81%, respectively, compared to CRUS.
Conclusion
CRU should be selected as the recommended N fertilizer types, and the combination of CRU and RZF was the most effective choice for rice production.
Anthracycline-induced cardiomyopathy is a leading cause of late morbidity in childhood cancer survivors. Aberrant DNA methylation plays a role in de novo cardiovascular disease. Epigenetic processes ...could play a role in anthracycline-induced cardiomyopathy but remain unstudied. We sought to examine if genome-wide differential methylation at 'CpG' sites in peripheral blood DNA is associated with anthracycline-induced cardiomyopathy. This report used participants from a matched case-control study; 52 non-Hispanic White, anthracycline-exposed childhood cancer survivors with cardiomyopathy were matched 1:1 with 52 survivors with no cardiomyopathy. Paired ChAMP (Chip Analysis Methylation Pipeline) with integrated reference-based deconvolution of adult peripheral blood DNA methylation was used to analyze data from Illumina HumanMethylation EPIC BeadChip arrays. An epigenome-wide association study (EWAS) was performed, and the model was adjusted for GrimAge, sex, interaction terms of age at enrollment, chest radiation, age at diagnosis squared, and cardiovascular risk factors (CVRFs: diabetes, hypertension, dyslipidemia). Prioritized genes were functionally validated by gene knockout in human induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) using CRISPR/Cas9 technology. DNA-methylation EPIC array analyses identified 32 differentially methylated probes (DMP: 15 hyper-methylated and 17 hypo-methylated probes) that overlap with 23 genes and 9 intergenic regions. Three hundred and fifty-four differential methylated regions (DMRs) were also identified. Several of these genes are associated with cardiac dysfunction. Knockout of genes EXO6CB, FCHSD2, NIPAL2, and SYNPO2 in hiPSC-CMs increased sensitivity to doxorubicin. In addition, EWAS analysis identified hypo-methylation of probe 'cg15939386' in gene RORA to be significantly associated with anthracycline-induced cardiomyopathy. In this genome-wide DNA methylation profile study, we observed significant differences in DNA methylation at the CpG level between anthracycline-exposed childhood cancer survivors with and without cardiomyopathy, implicating differential DNA methylation of certain genes could play a role in pathogenesis of anthracycline-induced cardiomyopathy.
Grazing is a substantial threat to the sustainability of grassland ecosystems, while it is uncertain about the variety of plant and soil microbial community and the linkages between them limit the ...comprehensive understanding of grazing ecology. We conducted an experiment on the effects of the grazing regimes rotational grazing (RG), continuous grazing (CG), and grazing exclusion (GE) on an alpine meadow in Qinghai-Tibetan Plateau. The differences of plant community composition, soil microbial community assembly mechanism, and taxonomic and functional composition between grazing regimes were examined, and the relationship between plant species and the soil microbes was assessed by constructing a co-occurrence network. The results showed that the plant community composition varied with the grazing regimes, while the soil microbial community composition did not vary with the grazing regimes. The soil bacterial functional composition was similar under RG and CG, while the soil fungal functional composition was similar under GE and RG. The soil microbial community under all grazing regimes was assembled mainly according to stochastic rather than deterministic mechanisms, and RG and CG reduced the relative importance of the stochastic ratio. At the microbial phylum level, CG and GE increased the relative abundance of Acidobacteria and Armatimonadetes and CG and RG increased the relative abundance of Elusimicrobia. In the network of plant species and soil microbial classes, plants and bacteria themselves were mainly positively linked (symbiosis and promotion), while plants and soil microbes were mainly negatively linked (competition). There were five microbial generalists in the network, which connected with many microbes, and four showed no difference in their abundance among the grazing regimes. Overall, the stable key microbes in the network and the fact that many of the plants are unconnected with microbes weakened the impact of grazing-induced changes in the plant community on soil microbes, probably resulting in the stable soil microbial community composition. Moreover, there was still a dominant and tolerant plant species,
, that connected the plant and microbial communities, implying that the dominant plant species not only played a crucial role in the plant community but also acted as a bridge between the plants and soil microbes; thus, its tolerance and dominance might stabilize the soil microbial community.
In
this study, experimental results of conventional flotation and
carrier flotation were characterized by six commonly used flotation
kinetic models. Two statistical criteria (coefficient of ...determination,
R
2
, and root mean square error, RMSE) were used
for comparison of fitting performance of different models. All kinetic
models tested gave good levels of goodness of fit, but the second-order
model with rectangular distribution (model 6) provided the best fitting
performance for the experimental data of conventional flotation and
carrier flotation. On this basis, two parameters, that is, modified
flotation rate constant (
K
m
) and selectivity
index (SI), were used to evaluate the difference in flotation separation
selectivity between conventional flotation and carrier flotation.
Comparisons of
K
m
and SI values indicated
that carrier flotation significantly improved the flotation rate constant
of combustible materials and flotation separation selectivity of ultrafine
coal (−74 μm). In addition, measurements of average bubble
size and water recovery indicated that both the coalescence of bubbles
and the drainage of liquid in the froth were promoted when coarse
coal particles (contact angle >90°) were employed as the carrier
to assist the flotation recovery of ultrafine particles, which in
turn favored the inhibition effect of the entrainment of gangue materials
in carrier flotation compared to conventional flotation.
Introduction
This study aimed to provide the theoretical basis for formulating scientific and reasonable on-farm nitrogen (N) management measures and efficient strategic fertilization to understand ...the effects of localized N supply (LNS) and N fertilizer variety coupling on N transport and soil N balance in rice fields.
Methods
A 2-year field experiment (2020 and 2021) was conducted in Jingzhou, Hubei Province, which included the following six treatments: no N application (CK), farmers' fertilizer practice (FFP), and four LNS treatments, including two N application methods including mechanical side-deep fertilization (M) and root-zone fertilization (R), two N fertilizer types with urea (U), and controlled-release urea (CRU).
Results
Compared with FFP, LNS increased the N apparent translocation level from stems, sheathes, and leaves (TNT) and N uptake by 10.70–50.59% and 11.28–29.71%, respectively. In LNS, the levels of nitrite reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT) under R increased by 13.81, 9.56, and 15.59%, respectively, compared with those under M, resulting in a significant increase in TNT by 8.58% and N uptake by 1.87%. Regarding the N fertilizer type, CRU significantly increased chlorophyll content by 7.27%, superoxide dismutase (SOD) and catalase (CAT) by 14.78 and 29.95% (
p
< 0.05), and NR, GS, and GOGAT by 44.41, 16.12, and 28.41% (
p
< 0.05), respectively, compared with that in U, which contributed to N absorption and transport. Moreover, CRUR significantly decreased N apparent loss by 50.04% compared with CRUM (
p
< 0.05).
Discussion
Considering the risk of soil N leaching and environmental protection, R should be selected as the recommended fertilization method. The combination of CRU and R is the most effective fertilization approach.
Controlled-release urea (CRU) fertilizers are widely used in agricultural production to reduce conventional nitrogen (N) fertilization-induced agricultural greenhouse gas emissions (GHGs) and improve ...N use efficiency (NUE). However, the long-term effects of different CRU fertilizers on GHGs and crop yields in vegetable fields remain relatively unexplored. This study investigated the variations in GHG emissions at four growth stages of lettuce in the spring and autumn seasons based on a five-year field experiment in the North China Plain. Four treatments were setup: CK (without N application), U (conventional urea-N application), ON (20% reduction in urea-N application), CRU (20% reduction in polyurethane-coated urea without topdressing), and DCRU (20% reduction in polyurethane-coated urea containing dicyandiamide DCD without topdressing). The results show that N application treatments significantly increased the GHG emissions and the lettuce yield and net yield, and DCRU exhibited the lowest N
O and CO
emissions, the highest lettuce yield and net yield, and the highest lettuce N content of the N application treatments. When compared to U, the N
O emission peak under CRU and DCRU treatments was notably decreased and delayed, and their average N
O emission fluxes were significantly reduced by 10.20-20.72% and 17.51-29.35%, respectively, leading to a significant reduction in mean cumulative N
O emissions during the 2017-2021 period. When compared to U, the CO
fluxes of DCRU significantly decreased by 8.0-16.54% in the seedling period, and mean cumulative CO
emission decreased by 9.28%. Moreover, compared to U, the global warming potential (GWP) and greenhouse gas intensity (GHGI) of the DCRU treatment was significantly alleviated by 9.02-17.13% and 16.68-20.36%, respectively. Compared to U, the N content of lettuce under DCRU was significantly increased by 6.48-17.25%, and the lettuce net yield was also significantly increased by 5.41-7.71%. These observations indicated that the simple and efficient N management strategy to strike a balance between enhancing lettuce yields and reduce GHG emissions in open-field lettuce fields could be obtained by applying controlled-release urea containing DCD without topdressing.
Bubble-particle attachment is a key factor in various material processing such as wastewater treatment and flotation separation. Nanobubble's formation and its stability on hydrophobic surfaces with ...and without surfactants have been scientifically proven and extensively studied in various investigations. However, the influence of particle roughness on the hydrophilic particle-air bubble attachment, which could be completely different from hydrophobic particle-bubble attachment in the presence of nanobubbles, has not been addressed. For tackling this gap, the present work investigated the impact of nanobubbles on the roughed surfaces of glass bead particles. The temperature rise technique as a known method was used for micro/nanobubble size generation. The glass beads were modified by the commonly applied abrasion method to create different roughness magnitudes. The particle-bubble assessment results indicated that the particle roughness could potentially affect the bubble attachment of hydrophilic glass beads while the attachment area of smooth particles was almost zero. Outcomes also were revealed that the modified attachment rate constant increased from 0.1180 to 2.2802 s−1 with the increase of particle surface roughness, indicating a shortening of attachment performance by enhancing the particle surface roughness. However, it was observed that the temperature rise method could improve the particle-bubble attachment only to a marginal extent.
Open vegetable fields in China are a major anthropogenic source of nitrous oxide (N
O) emissions due to excessive nitrogen (N) fertilization. A 4 yr lettuce experiment was conducted to determine the ...impacts of controlled-release fertilizers (CRFs) and nitrification inhibitors (NIs) on lettuce yield, N
O emissions and net economic benefits. Five treatments included (i) no N fertilizer (CK), (ii) conventional urea at 255 kg N ha
based on farmers' practice (FP), (iii) conventional urea at 204 kg N ha
(OPT), (iv) CRF at 204 kg N ha
(CU) and (v) CRF (204 kg N ha
) added with NI (CUNI). No significant differences were found in the lettuce yields among different N fertilization treatments. Compared with FP, the cumulative N
O emissions were significantly decreased by 8.1%, 38.0% and 42.6% under OPT, CU and CUNI, respectively. Meanwhile, the net benefits of OPT, CU and CUNI were improved by USD 281, USD 871 and USD 1024 ha
compared to CN, respectively. This study recommends the combined application of CRF and NI at a reduced N rate as the optimal N fertilizer management for the sustainable production of vegetables in China with the lowest environmental risks and the greatest economic benefits.
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