Diversity of Arbuscular Mycorrhizal Fungi Associated with Six Rice Cultivars in Italian Agricultural Ecosystem Managed with Alternate Wetting and Drying

Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.

Statistical Prediction of Wet and Dry Periods in theComahue Region (Argentina)

General features of rainy season with excess or deficits are analyzed using standardized precipitation index (SPI) in Limay and Neuquen River basins. Results indicate that most of dry and wet periods persist less than three months in both basins. Furthermore, an increase of rainfall variability over time is observed in the Limay river basin but it is not detected in the Neuquen river basin. There is a tendency for wet (dry) periods to take place in El Ni?o (La Ni?a) years in both basins. Rainfall in both basins, have an important annual cycle with its maximum in winter. In addition, possible causes of extreme rainy seasons over the Limay River Basin are detailed. The main result is that the behavior of low level precipitation systems displacing over the Pacific Ocean in April influences the general hydric situation during the whole rainy season. In order to establish the existence of previous circulation patterns associated with interannual SPI variability, the composite fields of wet and dry years are compared. The result is that rainfall is related to El Ni?o- Southern Oscillation (ENSO) phenomenon and circulation over the Pacific Ocean. The prediction scheme, using multiple linear regressions, showed that 46% of the SPI variance can be explained by this model. The scheme was validated by using a cross-validation method, and significant correlations are detected between observed and forecast SPI. A polynomial model is used and it little improved the linear one, explaining the 49% of the SPI variance. The analysis shows that circulation indicators are useful to predict winter rainfall behavior.

Wetting alternating with partial drying during grain filling increases lysine biosynthesis in inferior rice grain

Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.

Grain yield and water use efficiency of super rice under soil water deficit and alternate wetting and drying irrigation

This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency （WUE） under alternate wetting and drying （AWD） irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered （WW）, moderate water deficit （MWD） and severe water deficit （SWD）. Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying （AWMD）, alternate wetting and severe drying （AWSD） and conventional irrigation （CI）. Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI,AWMD increased, whereasAWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and eitherAWMD orAWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.

Agronomic performance of drought-resistance rice cultivars grown under alternate wetting and drying irrigation management in southeast China

Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.

Influence of Seed Priming on Performance and Water Productivity of Direct Seeded Rice in Alternating Wetting and Drying

Direct seeded rice is promising alternative to traditional transplanting, but requires appropriate crop and water management to maintain yield performance and achieve high water productivity. Present study evaluated the effect of seed priming and irrigation on crop establishment, tillering, agronomic traits, paddy yield, grain quality and water productivity of direct seeded rice in alternate wetting and drying （DSR-AWD） in comparison with direct seeded rice at field capacity （DSR- FC）. Seed priming treatments were osmo-priming with KCI （2.2%）, CaCI2 （2.2%） and moringa leaf extracts （MLE, 3.3%） including hydro-priming as control. Among the treatments, seed osmo-primed with MLE emerged earlier and had higher final emergence, followed by osmo-priming with CaCI2. Tillering emergence rate and number of tillers per plant were the highest for seed priming with CaCI2 in DSR- AWD. Total productive and non-productive tillers, panicle length, biological and grain yields, harvest index were highest for seed priming with MLE or CaCI2 in DSR-AWD. Similarly, grain quality, estimated in terms of normal grains, abortive and chalky grains, was also the highest in DSR-AWD with MLE osmo-priming. Benefit cost ratio and water productivity was also the highest in DSR-AWD for seed priming with MLE. In conclusion, seed priming with MLE or CaCI2 can be successfully employed to improve the direct seeded rice performance when practiced with alternate wetting and drying irrigation.

Moderate wetting and drying increases rice yield and reduces water use, grain arsenic level, and methane emission

To meet the major challenge of increasing rice production to feed a growing population under increasing water scarcity,many water-saving regimes have been introduced in irrigated rice,such as an aerobic rice system,non-flooded mulching cultivation,and alternate wetting and drying(AWD).These regimes could substantially enhance water use efficiency(WUE) by reducing irrigation water.However,such enhancements greatly compromise grain yield.Recent work has shown that moderate AWD,in which photosynthesis is not severely inhibited and plants can rehydrate overnight during the soil drying period,or plants are rewatered at a soil water potential of-10 to-15 k Pa,or midday leaf potential is approximately-0.60 to-0.80 MPa,or the water table is maintained at 10 to 15 cm below the soil surface,could increase not only WUE but also grain yield.Increases in grain yield WUE under moderate AWD are due mainly to reduced redundant vegetative growth;improved canopy structure and root growth;elevated hormonal levels,in particular increases in abscisic acid levels during soil drying and cytokinin levels during rewatering;and enhanced carbon remobilization from vegetative tissues to grain.Moderate AWD could also improve rice quality,including reductions in grain arsenic accumulation,and reduce methane emissions from paddies.Adoption of moderate AWD with an appropriate nitrogen application rate may exert a synergistic effect on grain yield and result in higher WUE and nitrogen use efficiency.Further research is needed to understand root–soil interaction and evaluate the long-term effects of moderate AWD on sustainable agriculture.

Effect of irrigation regime on grain yield,water productivity,and methane emissions in dry direct-seeded rice grown in raised beds with wheat straw incorporation

Dry direct-seeded rice grown in raised beds is becoming an important practice in the wheat–rice rotation system in China.However,little information has been available on the effect of various irrigation regimes on grain yield,water productivity(WP),nitrogen use efficiency(NUE),and greenhouse gas emission in this practice.This study investigated the question using two rice cultivars in 2015 and 2016 grown in soil with wheat straw incorporated into it.Rice seeds were directly seeded into raised beds,which were maintained under aerobic conditions during the early seedling period.Three irrigation regimes:continuous flooding(CF),alternate wetting and drying(AWD),and furrow irrigation(FI),were applied from 4.5-leaf-stage to maturity.Compared with CF,both AWD and FI significantly increased grain yield,WP,and internal NUE,with greater increases under the FI regime.The two cultivars showed the same tendency in both years.Both AWD and FI markedly increased soil redox potential,root and shoot biomass,root oxidation activity,leaf photosynthetic NUE,and harvest index and markedly decreased global warming potential,owing to substantial reduction in seasonalThe results demonstrate that adoption of either AWD or FI could increase grain yield and resource-use efficiency and reduce environmental risks in dry direct-seeded rice grown on raised beds with wheat straw incorporation in the wheat–rice rotation system.

Growth,yield and water productivity of dry direct seeded rice and transplanted aromatic rice under different irrigation management regimes

Sustainability of traditionally cultivated rice in the rice-wheat cropping zone(RWCZ)of Pakistan is dwindling due to the high cost of production,declining water resources and escalating labour availability.Thus,farmers and researchers are compelled to find promising alternatives to traditional transplanted rice(TPR).A field study was conducted in Punjab,Pakistan,in 2017 and 2018 to explore the trade-offs between water saving and paddy yield,water productivity and economics of two aromatic rice varieties under dry direct seeded rice(DDSR)and TPR.The experiment was comprised of three irrigation regimes on the basis of soil moisture tension(SMT)viz.,continuous flooded(>–10 kPa SMT),alternate wetting and drying(AWD)(–20 kPa SMT)and aerobic rice(–40 kPa SMT),maintained under TPR and DDSR systems.Two aromatic rice verities:Basmati-515 and Chenab Basmati-2016 were used during both years of study.In both years,DDSR produced higher yields(13–18%)and reduced the total water inputs(8–12%)in comparison to TPR.In comparison to traditional continuous flooded(CF),AWD under DDSR reduced total water input by 27–29%and improved the leaf area index(LAI),tillering,yield(7–9%),and water productivity(44–50%).The performance of AWD with regard to water savings and increased productivity was much higher in DDSR system as compared to AWD in TPR system.Cultivation of DDSR with aerobic irrigation improved water savings(49–55%)and water productivity(22–30%)at the expense of paddy yield reduction(36–39%)and spikelet sterility.With regard to variety,the highest paddy yield(6.6 and 6.7 t ha–1)was recorded in DDSR using Chenab Basmati-2016 under AWD irrigation threshold that attributed to high tiller density and LAI.The economic analysis showed DDSR as more beneficial rice establishment method than TPR with a high benefit-cost ratio(BCR)when the crop was irrigated with AWD irrigation threshold.Our results highlighted that with the use of short duration varieties,DDSR cultivation in conjunction with AWD irrigation can be more beneficial for higher productivity and crop yield.

DRY/WET CLIMATE CHANGE SINCE 960 A.D.IN TAIHU DRAINAGE BASIN OF CHINA

ABSTRACT: The present study reconstructs an annual dry/wet grade series from 960 A. D. to 1992 A. D. in the Tai-hu drainage basin of eastern coast, China by collecting historical climatic records, to examine the climate periodicity and climate jumps. Power Spectrum analysis reveals that the dry/wet climate in the study area was a superposed phenomenon with the major period of quasi-100-year, and several other notable periods. These periods were supposed to be closely linked with the celestial activity. Climate jumps are detected using moving t-test. The two abrupt changes around 1247 - 1263 A. D. and 1618 - 1635 A. D. are proved as regional events. The 14th to 15th century appeared as the wettest period during the last 1000 years in the Taihu drainage basin. These are interpreted as the consequence of east Asia climate change.

Transformation and mechanisms of climate wet/dry change on the northern Tibetan Plateau under global warming:A perspective from paleoclimatology

The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds.In summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,westerly winds mainly control the climate.This article compares the wet/dry changes in the region during the mid-Holocene(MH)warm period,the medieval climate anomaly(MCA),the current warm period(CWP),and the future warm period from the perspective of paleoclimate.We found that the MH warm period was mainly affected by the orbit-controlled East Asian summer monsoon,and the region showed warm and humid climate characteristics.The MCA was mainly controlled by solar radiation,and there was a warm and dry phenomenon.The CWP and the future warm period are mainly controlled by the rise in temperature caused by the increase in greenhouse gases,and the climate is becoming more arid.The wet/dry patterns in the CWP and the future warm period in the next century on the northern Tibetan Plateau are similar to those in the MCA.Continued warming will lead to the expansion of the westerly belt and a gradually humid climate.The future wet/dry changes will be more similar to the MH warm period.

Determination of the Effect of the System of Rice Intensification (SRI) on Rice Yields and Water Saving in Mwea Irrigation Scheme, Kenya

Irrigated rice cultivation has long been associated with large amounts of water. Currently convectional rice production is faced with major challenges of water shortage as a result of increasing population sharing the same water resources, as well as global environmental changes. The System of Rice Intensification (SRI), as opposed to conventional rice production, involves alternate wetting and drying (AWD) of rice fields. The objective of this study was to determine the optimum drying days period of paddy fields that has a positive effect on rice yields and the corresponding water saving. The experimental design used was randomized complete block design (RCBD). Four treatments and the conventional rice irrigation method were used. The treatments were the dry days allowed after draining the paddy under SRI before flooding again. These were set as 0, 4, 8, 12 and 16 day-intervals. Yield parameters were monitored during the growth period of the crop where a number of tillers, panicles, panicle length and panicle filling were monitored. Amount of water utilized for crop growth for each treatment was measured. Average yield and corresponding water saving were determined for each treatment. The results obtained show that the 8 days drying period gave the highest yield of 7.13 tons/ha compared with the conventional method of growing rice which gave a yield of 4.87 tons/ha. This was an increase of 46.4% above the conventional method of growing rice. Water saving associated with this drying regime was 32.4%. This was taken as evidence that SRI improved yields with reduction in water use.

Effect of Nitrogen and Water Management on Methane Emission of Boro Rice Cultivation in Bangladesh

Water and nitrogen are two key elements required for successful rice cultivation. We examined the responses of nitrogen and water management on methane emission of Boro rice in the field laboratory of Bangladesh Agricultural University research farm, Mymensingh. Three treatments were studied in the field experiment viz, T1: Control plot (no nitrogen fertilizer), T2: Urea super granule (78 kg N/ha), T3: Prilled urea (104 kg N/ha) with three replications under two water management of Continuous Standing Water (CSW) and Alternate Wetting and Drying (AWD). Air samples were collected by the closed-chamber method and methane gas was determined by gas chromatography. The highest CH4 emission was found from CSW plots and the lowest from AWD plots. Under CSW condition, the effects of urea treatments on CH4 emission were not significant. In case of urea treatments, the highest CH4 emission was observed from treatment T3 under CSW condition and T2 under AWD condition and the lowest emission was from the control treatment. The overall results suggest that prilled urea and urea super granule should be applied under AWD and CSW condition, respectively to keep less CH4 emission from irrigated rice agriculture.

Temporal Dynamics of Standardized Precipitation Evapotranspiration Index and Its Influence to Summer Maize Yield from Kaifeng Region in He’nan Province

Many quantitative studies get more and more attention on drought occurrence and monitoring trends of drought change using different methods;however few studies involve correlation between drought and crop yield especially drought index. This study analyzed the climate change about annual mean SPEI-3, SPEI-6 and SPEI-12, of Kaifeng region in the period of 1961-2013. The SPEI-3 and SPEI-6 seasonal short timescales showed a decreasing tendency, especially rapidly a decline since 2004, and high-frequency alternate dry/wet periods occurred during 1961-2013. However, the annual timescale SPEI-12 showed almost no evidently rise/decline tendency but severity events of dry/wet episode aggravated in terms of duration and magnitude and remarkable low-frequency change. Correlation analysis results between maize yield from Kaifeng region and multi-month scale annual SPEI showed a high negative significant correlation with -0.689 (ρ ρ < 0.001) in June SPEI-3. Further analysis between maize yield and temperature, precipitation and light during June-September found that precipitation in June and August was the main limiting factor to maize yield and their correlation values were well below the correlation of SPEI-3 of June. Finally, the reconstruction equation found that there was a better change consistency between the maize yield reconstruction and actual production but more error in extremely high and low annual yield. This study provides a reliable analysis of climate change to corn yield and basic data support for services of grain production and food security in the future.

Influence of environmental factors on land-surface water and heat exchange during dry and wet periods in the growing season of semiarid grassland on the Loess Plateau

On the basis of information from the project ＂Land-surface Processes and their Experimental Study on the Chinese Loess Plateau＂, we analyzed differences in land-surface water and heat processes during the main dry and wet periods of the semiarid grassland growing season in Yuzhong County, as well as the influences of these environmental factors. Studies have shown that there are significant differences in changes of land-surface temperature and humidity during dry and wet periods. Daily average normalized temperature has an overall vertical distribution of ＂forward tilting＂ and ＂backward tilting＂ during dry and wet periods, respectively. During the dry period, shallow soil above 20-cm depth is the active temperature layer. The heat transfer rate in soil is obviously different during dry and wet periods. During the dry period, the ratio of sensible heat flux to net radiation （H/Rn） and the value of latent heat flux to net radiation （LE/Rn） have a linear relationship with 5-cm soil temperature; during the wet period, these have a nonlinear relationship with 5-cm soil temperature, and soil temperature of 16℃ is the critical temperature for changes in the land-surface water and heat exchange trend on a daily scale. During the dry period, H/Rn and LE/Rn have a linear relationship with soil water content. During the wet period, these have a nonlinear relationship with 5-cm soil water content, and 0.21 m^3 m^-3 is the critical point for changes in the land-surface water and heat exchange trend at daily scale. During the dry period, for vapor pressure deficit less than 0.7 kPa, H/Rn rises with increased vapor pressure deficit, whereas LEIRn decreases with that increase. When that deficit is greater than 0.7 kPa, both H/Rn and LE/Rn tend to be constant. During the wet period, H/Rn increases with the vapor pressure deficit, whereas LE/Rn decreases. The above characteristics directly reflect the effect of differences in land-surface environmental factors during land-surface water and heat exchange processes, and indirectly reflect the influences of cloud precipitation processes on those processes.

Adopting the system of rice intensification (SRI) in Tanzania: A review

The demand of water for irrigation purposes in Tanzania outstrips the amount of water available for irrigation and other demands. On the other hand, the demand for more food to feed the growing population is increasing, calling for the need to have technologies and farming practices that ensure more food production while minimizing water uses. Rice is among cereal crops grown in Tanzania, and it can assist in meeting the food demand for the nation. Majority of rice producers in Tanzania and Sub-Saharan Africa(SSA) are subsistence farmers and they practice continuous flooding, a technique that requires much water. In addition to using large amounts of water, the conventional practices of growing paddy using local varieties transplanting process are implemented when seedlings are more than 21 days old, and 3-4 seedlings are transplanted in one hole. This practice results in low yields, and low water productivity and water use efficiency. The system of rice intensification (SRI) on the other hand, is a promising new practice of growing paddy rice that has proven to be very effective in saving water and increasing rice yields in many parts of the world. SRI practice is spreading fast and it has been adopted in many countries. The SRI practice has been introduced in Tanzania during the last 3 years as such it is not widely practiced. This paper reviews SRI practice at global, regional and country (Tanzania) level, and evaluates the challenges, opportunities and implications for its adoption in Tanzania. Knowledge gaps at each level have been identified and discussed as well as suggestions for researchable areas.

Water Management of Falaj Al Khatmain in Sultanate of Oman

Oman is an arid country with an average annual rainfall of 100 mm. Agricultural productions in Oman is almost fully dependent on irrigation. More than one third of irrigation water is supplied by aflaj （singular： falaj）, which provide 680× 10^6 m^3 of water per year and irrigate some 26,500 ha. Aflaj are trenches and tunnels, which are dug in the ground to convey water from one place to another. This study analyzed the existing management of Falaj Al Khatmain and proposed improvements to the system regarding water utilization, enriching community living, distribution of water among the shareholders and the water circulation during day and night. Furthermore, the study estimated the surplus water during the wet period and determined the recharge area of groundwater using the rainfall, falaj flow, wadi flow, water table and lithology of the wells located in or around the study area. The study concluded that under the climatic and hydro-geologic conditions in the study area, the best arrangement for recharging the groundwater is an infiltration pond to store surplus water from thefalaj in the subsurface pond or reservoir without dam construction.

Effects of zeolite application on grain yield,water use and nitrogen uptake of rice under alternate wetting and drying irrigation

With the increasing scarcity of water resources and growing population,the dual goal of saving irrigation water and increasing grain yield has become a major challenge in rice production around the world.A two-year lysimetric experiment was conducted to assess the effects of zeolite application(Z_(0):0 and Z1:15 t/hm^(2) and water regimes(W_(0):continuous flooding irrigation,W1:energy-controlled irrigation,W2:alternate wetting and drying irrigation)on grain yield,water use and total nitrogen uptake of rice.Zeolite addition to paddy field significantly increased grain yield,total N uptake,and water use efficiency(WUE),despite a negligible effect on amount of irrigation water used.Compared with W_(0),the separate use of W_(1) and W_(2) each considerably decreased irrigation water.However,W2-grown rice showed a significant decline in grain yield.In contrast,W1 showed comparable grain yield with W_(0),and achieved the highest WUE.Correlation analysis revealed that grain yield was significantly and positively correlated with effective panicles,spikelets per panicle,water consumption,and total N uptake.It is concluded that the combination of zeolite application at the rate of 15 t/hm^(2) and energy-controlled irrigation could be recommended to benefit farmers by reducing irrigation water while improving grain yield on a clay loam soil.

Effects of Different Irrigation Management on the Textural Properties of Double-Cropping Late Indica Rice in South China

In order to investigate the effects of different irrigation management on the textural properties of two different double-cropping late indica rice,the effects of three irrigation management including conventional irrigation(CK),constant irrigation(CI)and alternate wetting and drying(AWD)on textural properties has been researched under field conditions of two years.The results indicated that the firmness,cohesiveness and chewiness were decreased under AWD treatment,and the stickiness was increased compared with CK,while the textural properties under CI treatment showed the opposite trend with AWD treatment.Additionally,AWD treatment signifi-cantly improved the springiness of TY871 compared with CK and CI treatment,but had no significant effect in RYHZ,suggesting improvement of the cooking and eating quality of TY871 under AWD treatment.Correlation analysis showed that the chewiness was positively correlated with the firmness and cohesiveness,and the cohesiveness was positively correlated with the firmness.AWD could promote the textural properties of high-quality late indica rice in South China whereas CI treatment has shown the disadvantage of the textural properties,which will provide useful information for the improvement of cooking and eating quality of rice.

Corrosion Behavior of Weathering Test Steel for Bridge Under the Neutral Wet/Dry Alternate Condition

The corrosion behaviors of the high-performance weathering test steel for bridge and the reference (09CuPCrNi-A) were symmetrically studied under 3.5% NaCl neutral wet/dry alternate condition,revealing their dynamics line tendency of primary corrosion and the rusting flow in the simulative marine atmosphere environment.By observing the corrosion evolution of surface microstructures and composition by the scanning electronic microscope (SEM) and the energy dispersive spectrometer (EDS) at the different stages,the corrosion mechanism was further discussed in details.