LONG-TERM IMPACT OF TILLAGE AND CROPPING MANAGEMENTS ON SOIL HYDRO-PHYSICAL PROPERTIES AND YIELD

Soil physical and hydraulic properties control the major soil functions related to the imbibition, transmission and retention of water, air, heat and nutrients. Adoption of no-tillage in Tennessee through the last decades has considerably decreased the fluvial soil losses. However, the long-term effect of no-tillage on soil hydro-physical properties and its interaction with companion practices such as cover crops and crop sequence has not been fully discovered.In this project, three long-term experiments located in West Tennessee Research and Education Center in Milan and Jackson, TN were studied in 2015 and 2016 for soil hydro-physical properties. The effect of 34 years of tillage, fertilization and cover crop, 15 years of crop rotation on no-tillage with winter fallow and 37 years of a range of tillage intensities and no-tillage with and without cover crop on soil physical properties were assessed. Relationship between soil physical properties were determined and by relating the soil physical properties to corn, cotton and soybean yield and long-term yield stability, the most effective cropping and tillage managements were identified.Long-term no-tillage substantially improved soil aggregation, water infiltration and transmission and cotton yield than conventional tillage. Effect of cover crops on measured soil physical properties were less evident than the effect of no-tillage. However, planting hairy vetch and wheat cover crops improved the soil aggregation and increased the water infiltration and transmission significantly compared with no cover crop. No-tillage planted with hairy vetch cover crop experienced significantly higher quasi-steady and cumulative infiltration compared with the other treatment combinations in both years. Cropping corn, cotton and soybean in double cropping sequences did not favor soil in improved physical quality than monoculture while existence of corn in cropping system either as continuous cropping or in sequence improved soil physical quality. Corn rotated with soybean and cotton increased yield and decreased the long-term variance in soybean yield. Under sub-humid climate of Tennessee with relatively high decomposition rate of organic matter, the magnitude of residue turnover and below-ground root activity was found to be key factors increasing the no-tillage potential for additional improvement in soil quality and yield

Progesterone exerts antidepressant-like effect in a mouse model of maternal separation stress through mitigation of neuroinflammatory response and oxidative stress

Context: Experiencing early-life adversity plays a key role in the development of mood disorders in adulthood. Experiencing adversities during early life period negatively affects brain development. Sex steroids such as progesterone affect the brain structure and functions and subsequently affects behaviour. Objective: We assess the antidepressant-like effect of progesterone in a mouse model of maternal separation (MS) stress, focussing on its anti-neuroinflammatory and antioxidative effects. Materials and methods: NMRI mice were treated with progesterone (10, 50, and 100 mg/kg, i.p., respectively) for 14 days. Valid behavioural tests including forced swimming test (FST), splash test and open field test (OFT) were used. Quantitative reverse transcription-PCR (qRT-PCR) was used for evaluation of genetic expression in the hippocampus. Antioxidant capacity was assessed by the FRAP method and the level of malondialdehide by TBA. Results: MS provoked depressive-like behaviour in mice. Treatment of MS mice with progesterone increased the grooming activity time in the splash test and decreased the immobility time in the FST. In addition, progesterone decreased the expression of inflammatory genes related to neuroinflammation (IL-1 beta, TNF-alpha, TLR4 and NLRP3) as well as increased the antioxidant capacity and decreased the lipid peroxidation (MDA) in the hippocampus. Discussion and Conclusion: Administration of progesterone significantly mitigated the negative effects of MS on behaviours relevant to depressive-like behaviour as well as attenuated neuro-immune response and oxidative stress in the hippocampus of MS mice. In this context, we conclude that progesterone, at least partially, via attenuation of oxidative stress and neuroinflammation, exerts antidepressant-like effects

Comparison of Flexural Strength of Mineral Trioxide Aggregate, Calcium-enriched Mixture and BioAggregate

Introduction: The aim of this study was to compare the flexural strength of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM), and BioAggregate (BA). Methods and Materials: In this study, the flexural strength of materials was measured using a 3-point bend test. After being prepared, MTA, CEM, and BA were inserted into the intra-putty molds using amalgam plugger. The specimens were covered with a sponge wetted with synthetic tissue fluid (STF) and incubated for 96 h. They were then subjected to a 3-point bend test using Universal Testing Machine. The Kruskal-Wallis and Mann-Whitney U tests were used to compare flexural strength in groups. In this study, P<0.05 was considered as the significant level. Results: There were significant differences between the three groups in terms of the flexural strength (P<0.001). The mean flexural strength in the BA, CEM, and MTA groups were 27.32±2, 9.09±1.16, and 10.25±1.6, respectively. Pairwise comparison showed significant differences between the three groups. Conclusion: This in vitro study showed that BA has the highest and CEM has the lowest flexural strength.Keywords: BioAggregate; CEM Cement; Flexural Strength; Mineral Trioxide Aggregate

Precision Agriculture Concept: Distribution Pattern of Selected Soil and Crop Characteristics Influenced by Fertigation

The main objective of this research was to determine spatial and temporal variability in a sugar beet filed affected by fertigation by sprinklers to develop a management strategy based on spatial and temporal variability of soil properties and sugar beet performance. The Location of the study area was in Isfahan Province, Iran. To describe the variability of soil and plant status, response to N fertilizer application by sprinklers was studied by analyzing 5 soil elements including N, K, CEC, EC and OM at two times (before and after fertigation) as well as 4 crop properties including tuber moisture content, tuber weight, number of tubers per square meter and tuber sugar content. Results were used to produce spatial and temporal variability maps. Data analysis and map visualization indicate that the higher moisture content causes heavier tuber but the grid which has more number of tubers has the lighter tubers. On the other hand, more tubers with lighter weight have higher sugar content. Matrix correlation of soil and plant properties shows a positive correlation of N in the soil to tuber weight, and tuber moisture while it has a negative correlation to sugar content and number of tubers. Higher sugar content of tubers was achieved compared to previous records of this field and the average of tuber sugar content for the Isfahan province. Fertigation by sprinkler irrigation is beneficial for the high and uniform tuber sugar content (as the economical elements in sugar beet production) of sugar beet in the irrigated area

The potassium status of some representative Arizona soils

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Nanoscale Phenomena in Ultrathin Catalyst Layers of PEM Fuel Cells: Insights from Molecular Dynamics

Ionomer-free ultrathin catalyst layers have shown promise to enhance the performance and reduce the platinum loading of catalyst layers in polymer electrolyte fuel cell. The nanostructure of a catalyst layer affects the distribution and diffusion of reactants, and consequently its effectiveness factor. We employed classical molecular dynamics to simulate a catalyst layer pore as a water-filled channel with faceted walls, and investigated the effect of channel geometry and charging on hydronium ion and water distribution and diffusion in the channel.Equilibrium hydronium ion distribution profiles on the catalyst channel were obtained to calculate the effect of channel structure on the electrostatic effectiveness factor of the channel. Furthermore, we calculated the self-diffusion coefficient and interfacial water structure in the model channel. Results on proton concentration, diffusion and kinetics are discussed in view of catalyst layer performance