The Longmen Cloud Physics Field Experiment Base, China Meteorological Administration

Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration and the Chinese Academy of Meteorological Sciences jointly set up the Longmen Cloud Physics Field Experiment Base,China Meteorological Administration. This paper introduces the instruments and field experiments of this base, provides an overview of the recent advances in retrieval algorithms of microphysical parameters, improved understanding of microphysical characteristics, as well as the formation mechanisms and numerical prediction of heavy rainfalls in south China based on the field experiments dataset.

Uncertainty aversion and farmers' innovative seed adoption:Evidence from a field experiment in rural China

Based on the microdata of 705 wheat farmers in the Loess Plateau, this study empirically analyzes the impact of uncertainty on farmers' adoption of innovative seeds using a field experiment. The results indicate that farmers are generally ambiguity-averse and risk-averse. In addition, farmers with higher ambiguity aversion and risk aversion are less likely to adopt innovative wheat seeds, where their risk aversion plays a dominant role. Enhancing information access will alleviate the negative influence of ambiguity aversion on farmers' adoption of innovative seeds, and interlinked insurance and credit contracts will be beneficial to ease the adverse effect of risk aversion on the adoption of innovative wheat seeds. Meanwhile, heterogeneity analysis reveals that the inhibitory effects of ambiguity aversion and risk aversion on innovative seed adoption are more significant among farmers with lower education and household income.The government can establish both ex-ante and ex-post relevant guarantee mechanisms to help farmers preferably cope with various uncertainties in the production process, remitting farmers' ambiguity aversion and risk aversion to enhance new agricultural technology adoption rates.

Influence of magnetic field on power deposition in high magnetic field helicon experiment

Based on high magnetic field helicon experiment(HMHX), HELIC code was used to study the effect of different magnetic fields on the power deposition under parabolic distribution. This paper is divided into three parts: preliminary calculation, actual discharge experiment and calculation. The results of preliminary calculation show that a magnetic field that is too small or too large cannot produce a good power deposition effect. When the magnetic field strength is 1200 Gs,a better power deposition can be obtained. The actual discharge experiment illustrates that the change of the magnetic field will have a certain influence on the discharge phenomenon. Finally, the results of verification calculation successfully verify the accuracy of the results of preliminary simulation. The results show that in the actual discharge experiment, it can achieve the best deposition effect when the magnetic field is 1185 Gs.

Field experiment of rainfall infiltration on a soil slope and simulations based on a water-air two-phase flow model

Rainfall infiltration on a soil slope is usually an unsaturated seepage process that can be described by a water-air two-phase flow model.The effect of pore air pressure on rainfall infiltration has been widely recognized and validated by means of numerical simulations and laboratory experiments.However,whether a slope can actually seal pore air continues to be debated by researchers.In this study,a water-air two-phase flow model is used to simulate the rainfall infiltration process on a soil slope,and a field experiment is conducted to realistically test the sealing conditions of a slope.According to the numerical simulation,the areas of water and air flow in and out on the slope surface are relatively stable and can be classified as the“inhalation zone”and“overflow zone”,respectively.Intermittent rainfall on the soil slope has an amplifying effect on pore air pressure because rainfall intensity is usually at the millimeter level,and it causes pore air pressure to reach the cm level.A field experiment was performed to determine whether a slope can realistically seal pore air and subsequently verify the regularity of rainfall infiltration.Air pressure sensors were buried in the slope to monitor the pore air pressures during the rainfall process.The monitoring results show that the pore air pressure in the slope changed,which indicates that the slope can seal air.Moreover,the amplification effects of intermittent rainfall on pore air pressure were observed for natural rainfall,which agrees well with the numerical simulation results.

Propagation Characterization and Analysis for 5G mmWave Through Field Experiments

The 5G network has been intensively investigated to realize the ongoing early deployment stage as an effort to match the exponential growth of the number of connected users and their increasing demands for high throughput,bandwidth with Quality of Service(QoS),and low latency.Given that most of the spectrums below 6 GHz are nearly used up,it is not feasible to employ the traditional spectrum,which is currently in use.Therefore,a promising and highly feasible effort to satisfy this insufficient frequency spectrum is to acquire new frequency bands for next-generation mobile communications.Toward this end,the primary effort has been focused on utilizing the millimeter-wave(mmWave)as the most promising candidate for the frequency spectrum.However,though the mmWave frequency band can fulfill the desired bandwidth requirements,it has been demonstrated to endure several issues like scattering,atmospheric absorption,fading,and especially penetration losses compared to the existing sub-6 GHz frequency band.Then,it is fundamental to optimize the mmWave band propagation channel to facilitate the practical 5G implementation for the network operators.Therefore,this study intends to investigate the outdoor channel characteristics of 26,28,36,and 38 GHz frequency bands for the communication infrastructure at the building to the ground floor in both Line of Sight(LOS)and Non-Line of Sight(NLOS)environments.The experimental campaign has studied the propagation path loss models such as Floating-Intercept(FI)and Close-In(CI)for the building to ground floor environment in LOS and NLOS scenarios.The findings obtained from the field experiments clearly show that the CI propagation model delivers much better performance in comparison with the FI model,thanks to its simple setup,accuracy,and precise function.

Efficacy of Some Botanical Extracts on the Control of Late Blight Disease in Experimental Potato Field

Late blight caused by Phytophthora infestans (Mont.) De Bary is the most devastating disease of potato. This study was carried out to evaluate the efficacy of ten botanical extracts against the late blight disease incidence and severity in experimental potato field at University of Rajshahi, Bangladesh during 2019-2020. Crude aqueous extract of leaves of Syzygium cumini, Psidium guajava, Eucalyptus globusus, Carica papaya and Lawsonia inermis;fruits of Terminalia bellirica, T. chebula and Piper nigrum;flower buds of Syzygium aromaticum and cloves of Allium sativum were used at 5% (w/v) concentration for evaluation. Out of ten botanicals, Syzygium cumini leaves extract was found most effective in controlling the late blight disease incidence and severity up to 66 DAS (days after sowing) and increased the potato yield by 71.29% compare to untreated control. The efficacy of Lawsonia inermis extract against late blight disease was found promising and increased the potato yield by 48.51%. Other four botanical extracts (Terminalia chebula, Piper nigrum, Syzygium aromaticum and Carica papaya) showed moderate efficacy against the incidence and severity of late blight disease, and increased 30% more potato yield compare to control. These results suggest that botanical extract of Syzygium cumini has a great potential as an alternative of chemical fungicides to control the late blight disease of potato in eco-friendly way.

Field test of high-power microwave-assisted mechanical excavation for deep hard iron ore

Microwave-assisted mechanical excavation has great application prospects in mines and tunnels,but there are few field experiments on microwave-assisted rock breaking.This paper takes the Sishanling iron mine as the research object and adopts the self-developed high-power microwave-induced fracturing test system for hard rock to conduct field experiments of microwave-induced fracturing of iron ore.The heating and reflection evolution characteristics of ore under different microwave parameters(antenna type,power,and working distance)were studied,and the optimal microwave parameters were obtained.Subsequently,the ore was irradiated with the optimal microwave parameters,and the cracking effect of the ore under the action of the high-power open microwave was analyzed.The results show that the reflection coefficient(standing wave ratio)can be rapidly(<5 s)and automatically adjusted below the preset threshold value(1.6)as microwave irradiation is performed.When using a right-angle horn antenna with a working distance of 5 cm,the effect of automatic reflection adjustment reaches the best among other antenna types and working distances.When the working distance is the same,the average temperature of the irradiation surface and the area of the high-temperature area under the action of the two antennas(right-angled and equal-angled horn antenna)are basically the same and decrease with the increase of working distance.The optimal microwave parameters are:a right-angle horn antenna with a working distance of 5 cm.Subsequently,in further experiments,the optimal parameters were used to irradiate for 20 s and 40 s at a microwave power of 60 kW,respectively.The surface damage extended 38 cm×30 cm and 53 cm×30 cm,respectively,and the damage extended to a depth of about 50 cm.The drilling speed was increased by 56.2%and 66.5%,respectively,compared to the case when microwaves were not used.

Practical studies on rockfall simulation by DDA

In this paper,simulations of real rockfall by discontinuous deformation analysis (DDA) are conducted.In the simulations,the energy losses of rockfall are categorized into three types,i.e.the loss by friction,the loss by collision,and the loss by vegetation.Modeling of the energy loss using absolute parameters is conducted by the DDA method.Moreover,in order to verify the applicability and validity of the proposed DDA,field tests on rockfall and corresponding simulations of rockfall tests by DDA are performed.The simulated results of rockfall velocity and rockfall jumping height agree well with those obtained from the field tests.Therefore,the new technique properly considers the energy-absorption ability of slope based on vegetation condition and shape of the rockfall,and provides a new method for the assessment and preventive design of rockfall.

Design and Experiment of four Lines Trailed Potato Fertilization Seeder

In order to solve the problems which are widespread in potato seeding planter, such as lower operating efficiency, unideal performance index, higher replay rate and leakage rate and uneven spacing sowing in seeding operating, a trailed potato fertilization seeder was designed. The key components of the special structure had been got through the description of the structure and working principle of the whole machine. A crossing seed-taken technology along with the vibration component was adopted to achieve precision seeding. The results showed in the field test of the machine: all the performance indexes of the machine met the agronomic requirement of potato planting; the multiple and missing index were low; it completed the ditching, fertilizing, seeding as well as ridging in one planting process; its operation efficiency was high and the stability was good. This design of the trailed potato fertilization seeder provided a reference for the development of large traction-type potato seeding machine.

Preparation and efficacy evaluation of Paenibacillus polymyxa KM2501-1 microbial organic fertilizer against root-knot nematodes

Root-knot nematodes(RKNs) cause huge yield losses to agricultural crops worldwide. Meanwhile, livestock manure is often improperly managed by farmers, which leads to serious environmental pollution. To resolve these two problems, this study developed a procedure for the conversion of chicken manure to organic fertilizer by larvae of Hermetia illucens L. and Bacillus subtilis BSF-CL. Chicken manure organic fertilizer was then mixed thoroughly with Paenibacillus polymyxa KM2501-1 to a final concentration of 1.5×10^(8)CFU g^(-1). The efficacy of KM2501-1 microbial organic fertilizer in controlling root-knot nematodes was evaluated in pot and field experiments. In pot experiments, applying KM2501-1 microbial organic fertilizer either as a base fertilizer or as a fumigant at the dose of 40 g/pot suppressed root-knot disease by 61.76 and 69.05% compared to the corresponding control treatments, respectively. When applied as a fumigant at the dose of 1 kg m;in field experiments, KM2501-1 microbial organic fertilizer enhanced the growth of tomato plants, suppressed root-knot disease by 49.97%, and reduced second stage juveniles of RKN in soil by 88.68%. KM2501-1 microbial organic fertilizer controlled RKNs better than commercial bio-organic fertilizer in both pot and field experiments. These results demonstrate that this co-conversion process efficiently transforms chicken manure into high value-added larvae biomass and KM2501-1 microbial organic fertilizer with potential application as a novel nematode control agent.

Antidepressant Effect of Shenwei Ningyu Tablets on Rat Chronic Stress Model and Mouse Tail Suspension Model

[Objectives]To explore the antidepressant effect of Shenwei Ningyu Tablet,a new antidepressant traditional Chinese medicine,on rat chronic stress depression model and mouse tail suspension models.[Methods]Rat chronic stress model:except for the normal group,the rats in other groups were given corresponding chronic stress,and administered by gavage 1 h before modeling,for a total of 21 d.The changes of each indicator before and after the experiment were observed through the body weight change,the sugar water test,and open field test.The relevant hormone levels were detected by radioimmunoassay.Mouse tail suspension depression model:after continuous administration for 7 d,the activity times was recorded with the mouse automatic recorder,and the mouse immobility time was recorded after tail suspension,to explore the effects of each administration group on the tail suspension immobility time of mice.[Results]Chronic stress depression model:21 d after modeling,compared with the normal group,rats in the model group exhibited significantly reduced body weight,sucrose preference index,and horizontal and vertical movement scores(P<0.05).Compared with the model group,the low-dose Shenwei Ningyu Tablets group had significant differences in the sugar water test,horizontal and vertical movement scores(P<0.05).In addition,all three dose groups of Shenwei Ningyu Tablets could effectively reduce the content of CRF in chronic stress model rats,and the low dose group could significantly reduce the ACTH level in model rats(P<0.05).Mouse tail suspension depression model:the immobility time after tail suspension in each administration group was significantly different from that in the model group(P<0.05).[Conclusions]Shenwei Ningyu Tablets has a certain anti-depression effect on both the rat chronic stress depression model and the mouse tail suspension depression model.

General structure design and field experiment of pneumatic rice direct-seeder

In order to meet the requirement of field direct seeding for super hybrid rice:1-3 seeds per hill,a pneumatic rice direct-seeder with six seeding metering devices was designed.Transmission system of pneumatic rice direct-seeder and seed metering device were analyzed in this study.And the pipeline structure and vortex pump were designed and selected.The pressure distribution of the pipeline was tested.The pressure value of each sub-pipeline under the conditions of different main pipeline pressure value was obtained and the reasons for pressure loss were analyzed.The results showed that the variation coefficient between sub-pipelines was less than 5%.The pipeline pressure could be evenly distributed.Further,the field experiments were carried out on super hybrid rice Peizataifeng using two-factor testing,by which the effects of different negative pressure and different forward speed(namely,rotational speed of suction plate)for seeding precision were studied.It found that:(1)the optimal negative pressure was 2 kPa;(2)under the optimal negative pressure,the probabilities of 1-3 seeds per hill for the direct-seeder were 93.41%,95.47%and 97.50%,respectively,when the forward speed of the direct-seeded was high,medium and low speed;(3)the probability of empty hole was less than 2%,which satisfied the field direct seeding requirements of super hybrid rice.Additionally,hill spacing was measured,and the factors affecting the hill spacing were analyzed.The results showed that the fluctuation of hill spacing in the small range will not affect the seeding effect.In this study,a new type of pneumatic rice direct-seeder was designed.The main working components were tested and analyzed.The best parameters of field work were obtained.It provides the basis for the field application of the pneumatic rice precision seeder.

Optimized design and field experiment of a staggered vibrating subsoiler for conservation tillage

Soil compaction is a common problem facing conservation fields that restricts crop root growth and causes yield decrease.Subsoil techniques have been developed to break up the compaction layer.However,subsoil implement requires large draft power that hampered the development of subsoil techniques for most of developing countries due to lack of large scale tractors.Aiming to optimize the penetration resistance of the subsoiler and create a good working environment for the operators,a staggered vibrating subsoiler was developed.A new staggered vibrating mechanism was designed to generate the staggered vibration of the shanks meanwhile the V-shape shanks arrangement was adopted to keep relative balance for the subsoiler.In order to obtain optimum working parameters of the vibration frequency and forward speed,the trajectory of shanks was simulated by using the MATLAB software.The forward speed of 2-3 km/h with vibration frequency of 12 Hz was recommended to acquire an effective decrease in draft force.Field performance of this subsoiler was evaluated in terms of the draft force,power requirement and tractor wheel slippage.By comparing the two operation modes,staggered vibrating(SV)and rigid(NV)of shanks,the decrease ratios of draft force for SV were determined by 16.97%,12.12%and 9.02%at forward speeds of 2.2 km/h,2.6 km/h and 3.1 km/h,respectively.This is better than the research for the 1SZ-460 vibratory subsoiler that was decreased by 9.09%in draft force.The power requirement for SV was not significantly greater than that for NV.The obviously decreased wheel slippage was observed for SV by decrease of 12.47%,17.96%and 21.79%at forward speeds of 2.2 km/h,2.6 km/h and 3.1 km/h,respectively.In conclusion,the staggered vibrating subsoiler presents preferable working performance and is recommended to be applied in subsoil tillage process for developing countries.

Remediation of arsenic-contaminated paddy field by a new iron oxidizing strain(Ochrobactrum sp.)and iron-modified biochar

Iron-oxidizing strain(FeOB)and iron modified biochars have been shown arsenic(As)reme-diation ability in the environment.However,due to the complicated soil environment,few field experiment has been conducted.The study was conducted to investigate the potential of iron modified biochar(BC-FeOS)and biomineralization by a new found FeOB to remediate As-contaminated paddy field.Compared with the control,the As contents of G_(B)(BC-FeOS),G_(F)(FeOB),G_(FN)(FeOB and nitrogen fertilizer),G_(BF)(BC-FeOS and FeOB)and G_(BFN)(BC-FeOS,FeOB and nitrogen fertilizer)treatments in pore water decreased by 36.53%-80.03%and the microbial richness of iron-oxidizing bacteria in these treatments increased in soils at the rice maturation stage.The concentrations of available As of G_(B),G_(F),G_(FN),G_(BF) and G_(BFN) at the tillering stage were significantly decreased by 10.78%-55.48%.The concentrations of non-specifically absorbed and specifically absorbed As fractions of G_(B),G_(F),G_(FN),G_(BF) and G_(BFN) in soils were decreased and the amorphous and poorly crystalline hydrated Fe and Al oxidebound fraction was increased.Moreover,the As contents of G_(B),G_(F),G_(FN),G_(BF) and G_(BFN) in rice grains were significantly decreased(*P<0.05)and the total As contents of G_(FN),G_(BF) and G_(BFN) were lower than the standard limit of the National Standard for Food Safety(GB 2762-2017).Compared with the other treatments,G_(BFN) showed the greatest potential for the effective remediation of As-contaminated paddy fields.

Vibration analysis and topology optimization of the header of full-feeding rice combine harvester

The header frame of full-feeding rice combine harvester was characterized by severe vibration due to the excitation force generated by the movement of each working part.In order to solve the problem,the parametric model of the header frame was established,and the accuracy of the finite element model was verified by comparison of the results of the free modal analysis and free vibration modal test based on Eigensystem Realization Algorithm(ERA).Then the constrained modal frequencies were calculated and compared with the external excitation source frequencies,the results showed that the first and eighth order modal natural frequencies were coupled with the excitation frequencies of the threshing cylinder and the engine respectively,which were apt to resonate.To avoid resonance and achieve lightweight design,topology optimization,and finite element analysis were carried out.The optimization results showed that the strength and rigidity meet the requirements and the weight was 14.17%lower than before.The first and eighth order modal natural frequencies were far away from the excitation frequencies range of the threshing cylinder and engine,and the frequencies were far away from the range of each excitation frequency,which effectively avoided the occurrence of resonance.Field experiments showed that the peak value of the vibration acceleration in the three directions of the 8 measuring points of the optimized header frame was significantly reduced,which effectively reduced the vibration of the header frame during harvest.This study provides a method for obtaining the vibration characteristics of key components of agricultural machinery and provides a reference for the weight and vibration reduction of header frames of rice,wheat,rape,and other crop combine harvesters.

Methylselenized glucose:An efficient organoselenium fertilizer enhancing the selenium content in wheat grains

Selenium(Se)is an essential mineral element for human and other animals,and has been proved to improve plant growth and development and tolerance to different abiotic stresses.Selenium biofortification is considered to be a key strategy to increase the selenium content of edible parts of crops,which is helpful for improving human health.In this work,foliar fertilization with different concentrations and selenium forms was carried out on two wheat varieties at the flowering stage to compare the selenium enrichment effect of Na_(2)SeO_(3),methylselenized selenocysteine(MSC),methylselenized glucose(MSG)and methylselenized lactide(MSL)in wheat grains.Surprisingly,MSG was found to be the preferable fertilizer.After the application of MSG,the highest selenium content in wheat gains reached 6 mg/kg in this experiment,and the average selenium content was 2-4 times versus that of Na_(2)SeO_(3)application.Since MSG has high utilization rate and is easily available at relatively low cost,it can be employed as a potential selenium source for selenium biofortification to enhance the added value of agricultural industry.

Repellent effect of synanthropic house mouse urine odor on small forest mammals

In this study,we examined the effect of synanthropic house mouse(Mus musculus)urine odor on catching probability of small mammals to live traps.We conducted a series of field experiments in August 2016 and 2017 in a natural forests of the northwestern Moscow Region(Russia).Small mammals were trapped at two 4-ha fields using capture-mark-recapture technique by setting 200 live traps(100 points,2 traps per point)within each field.One trap in each pair was odorless(control)with bait only,whereas the other one was odor-baited with 20μL of the urine of a synanthropic house mouse.Further analysis was based on the data collected from 2 rodent species(bank vole Myodes glareolus,herb field mouse Apodemus uralensis)and 3 shrew species(common shrew Sorex araneus,Laxmann’s shrew Sorex caecutiens,and Eurasian pygmy shrew Sorex minutus).As a result,only bank voles significantly avoided odor-baited live traps.Using generalized linear mixed models,we showed that the choice of a trap by bank voles depended on their age,whereas the probability of repeated capture to a certain live trap was related to their prior experience.We discuss the possible role of components of synanthropic house mouse urine in the population management of exoanthropic small mammals.

Inhibition of native arbuscular mycorrhizal fungi induced increases in cadmium loss via surface runoff and interflow from farmland

Arbuscular mycorrhizal fungi(AMF)can form symbiotic relationships with most crops,but their impact on the environmental migration of cadmium(Cd)in farmland is limited.A field experiment was per-formed in the rainy season(May-October)for two years in Cd-polluted farmland used for maize cultivation.A fungicide(benomyl)was used to specifically inhibit native AMF growth in the farmland.The growth and Cd uptake of maize and the Cd concentration and loss in runoff and interflow were investigated.Benomyl strongly and significantly inhibited AMF colonization rate in maize roots,reduced the contents of total and easily extractable glomalin-related soil protein(GRSP)in soil and the Cd uptake in maize roots,and increased the Cd uptake in shoots.Particulate Cd was the main form of Cd loss in runoff,while dissolved Cd was the main form of Cd leaching loss at depths of 20 cm and 40 cm.Inhibiting AMF increased the Cd concentration in runoff and interflow and promoted dissolved Cd loss in runoff and interflow at 20 cm depth by 34.7%and 68.0%and particulate Cd loss by 46.4%and 19.7%,respectively.Furthermore,the AMF colonization rate in maize roots and the GRSP content in soil were significantly positively correlated with Cd uptake in roots and negatively correlated with the concentration and loss of Cd in runoff and interflow.These results indicated that the benomyl-induced inhibition of native AMF promoted Cd transfer to maize shoots and increased Cd loss via runoff and interflow from polluted farmland.