Variation Characteristics of Root Traits of Different Alfalfa Cultivars under Saline-Alkaline Stress and their Relationship with Soil Environmental Factors

Soil salinization is the main factor that threatens the growth and development of plants and limits the increase of yield.It is of great significance to study the key soil environmental factors affecting plant root traits to reveal the adaptation strategies of plants to saline-alkaline-stressed soil environments.In this study,the root biomass,root morphological parameters and root mineral nutrient content of two alfalfa cultivars with different sensitivities to alkaline stress were analyzed with black soil as the control group and the mixed saline-alkaline soil with a ratio of 7:3 between black soil and saline-alkaline soil as the saline-alkaline treatment group.At the same time,the correlation analysis of soil salinity indexes,soil nutrient indexes and the activities of key enzymes involved in soil carbon,nitrogen and phosphorus cycles was carried out.The results showed that compared with the control group,the pH,EC,and urease(URE)of the soil surrounding the roots of two alfalfa cultivars were significantly increased,while soil total nitrogen(TN),total phosphorus(TP),organic carbon(SOC),andα-glucosidase activity(AGC)were significantly decreased under saline-alkaline stress.There was no significant difference in root biomass and root morphological parameters of saline-alkaline tolerant cultivar GN under saline-alkaline stress.The number of root tips(RT),root surface area(RS)and root volume(RV)of AG were reduced by 61.16%,44.54%,and 45.31%,respectively,compared with control group.The ratios of K^(+)/Na^(+),Ca^(2+)/Na^(+)and Mg^(2+)/Na^(+)of GN were significantly higher than those of AG(p<0.05).The root fresh weight(RFW)and dry weight(RDW),root length(RL),RV and RT of alfalfa were positively regulated by soil SOC and TN,but negatively regulated by soil pH,EC,and URE(p<0.01).Root Ca^(2+)/Na+ratio was significantly positively correlated with soil TN,TP and SOC(p<0.01).The absorption of Mg and Ca ions in roots is significantly negatively regulated by soilβ-glucosidase activity(BGC)and acid phosphatase activity(APC)(p<0.05).This study improved knowledge of the relationship between root traits and soil environmental factors and offered a theoretical framework for elucidating how plant roots adapt to saline-alkaline stressed soil environments.

Reflection on the Integrated Development of Marine Fisheries and Tourism Based on the Transformation of Fishery Facilities: A Case Study of Ningde City of Fujian Province, China

Based on the analysis on the current situation of marine fishery resources and development in Ningde City,this paper plans a spatial pattern for the integration of marine fishery and tourism of the“one belt,three zones,and multiple points”,designs key projects,analyzes the existing problems in the integrated development of fishery and tourism,and proposes relevant countermeasures and suggestions.

Dynamic Changes of Nitrogen in Saline-alkaline Paddy Field and Its Potential Environmental Impacts

[Objective] The paper was to study the dynamic changes of nitrogen in saline-alkaline paddy field and its potential environment impacts. [Method] With typical sodic saline-alkaline paddy fields of Songnen Plain as study object,field test method was used to explore the dynamic changes was strong alkof nitrogen in paddy field of the region and its potential impact on environment. [Result] The soil in test regionaline with high CEC and C/N ratios,as well as poor preserving capacity of fertilizer. During the two-year field experiment,the indicators of salinization fluctuated. Initially,the concentrations of total nitrogen and ammonia nitrogen reached their maximum values,then decreased over time as a result of heavy rain. The maximum of nitrate concentration appeared later than those of total nitrogen and ammonia nitrogen. Ammonia volatilization accounted for 18.9%-28.8% of the nitrogen loss. The total nitrogen concentration in surface water was higher than the national Class Ⅲ surface water environmental quality standard. The concentration of ammonia from the recession flow of agricultural field was considerably high,which would potentially threaten the fishery in the downstream of Chagan Lake. [Conclusion] The study provided theoretical basis for saline-alkaline soil management and conservation of water and fishery resources.

Colonization Characteristics and Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of Iris lactea in Songnen Saline-alkaline Grassland

To understand arbuscular mycorrhizal(AM)fungi resources and develop AM fungal species in ornamental plants with saline-alkaline tolerances,Iris lactea,which grows in the Songnen saline-alkaline grassland with a high ornamental value,was selected as the experimental material,and the colonization characteristics of its roots and the AM fungal diversity in its rhizosphere were explored.The results of the observations and calculations of mycorrhizae from ten different samples showed that AM fungi colonized the roots of I.lactea and formed Arum-type mycorrhizal structures.There was a significant correlation between soil spore density and pH value,while the colonization rate showed a fluctuating trend with increasing pH values.The observed colonization intensities were of Levels II(1%–10%)or III(11%–50%),and the vesicle abundances were of grades A2 or A3 among different sites.AM fungi produced a large number of mycelia and vesicles in the roots of I.lactea after colonization.Thirty-seven species belonging to 15 genera of AM fungi were isolated from the rhizosphere of I.lactea and identified by morphological identification.Funneliformis and Glomus were the dominant genera,accounting for 21.79%and 20.85%of the total number,respectively.F.mosseae and Rhizophagus intraradices were isolated in all samples with importance values of 58.62 and 51.19,respectively.These results are expected to provide a theoretical basis for the analysis of the salt tolerance mechanism of I.lactea and for the discovery,exploration and further screening of AM fungal resources with salinity tolerances in saline-alkaline soils.

Characteristics and Spatial Variability of Saline-Alkaline Soil Degradation in the Typical Yellow River Delta Area of Kenli County, China

As an important area of reserve land resources, the Yellow River Delta is faced with the problem of soil salinization. Grasping the characteristics of soil salinity as well as its spatial variation patterns is an important foundation of prevention, control and utilization of saline soil. This study selected Kenli County of the Yellow River Delta, obtained soil salinity data through field survey and lab experiment, and used statistical, GIS interpolation and buffer analysis methods to analyze the characteristics of soil salinity and its spatial variation patterns. Our results showed that the general soil salinity in the study area was mainly moderate and there was a significant positive correlation between different soil layers of 0 - 15 cm, 15 - 30 cm and 30 - 45 cm and soil salinity increased with the increase of soil depth. The areas with high soil salinity in each soil layer mainly distributed in the east near the Bo Sea in the county, while the areas with lower soil salinity mainly distributed in the southwest, centre and the two sides of the Yellow River in the northeast. Soil salinity showed a trend of decrease with the increase in distance to the Bo Sea, while stretching from the Yellow River, it showed increase tendency with the increase in distance to the Yellow River. The order from high soil salinity to low of different vegetation types was naked land → suaeda glauca → tamarix → vervain → reed → couch grass → paddy → cotton → winter wheat → maize;the order for different geomorphic types was depression → slightly sloping ground → slow hillock → high flood land. This study preliminary delineated the characteristics of soil salinity as well as its spatial variation patterns in the study area, and provided scientific basis for soil resource sustainable utilization in the Yellow River Delta.

Studies of community structure and seasonal dynamics of planktonic copepods in saline-alkaline ponds

Species abundance and seasonal succession of copepods in saline-alkaline ponds were studied in Zhaodian Fish Farm, Gaoqing County, Shandong Province, from 5 April 1997 to 1 September 1998. The results indicated that in the conditions of salinity ranging from 1.36 to 20 g/L, total alkalinity changing from 2.4 to 7.2 mmol/L and pH 8–9, zooplankton in saline-alkaline ponds was composed of freshwater salt-tolerated species or halophile species, some of which are halobiont species and usually occurs in freshwater. In our study, copepods were predominant in many fish-culture ponds and all control ponds without fishes in spring, late autumn and early winter. Dominant species of copepods were Sinocalanus tenellus, Cyclops vicinus, Thermocyclops taiho- kuensis. The biomass of copepods in the control ponds without fishes was higher than that of the fish-culture ponds.

Priming for Saline-Alkaline Tolerance in Rice:Current Knowledge and Future Challenges

Soil salinization and/or alkalization is a major constraint to crop production worldwide.Approximately 60% of the cultivated land is affected by salt,over half of which is alkalized.Alkaline soils are characterized by high alkalinity and typically high salinity,which creates a complex saline-alkaline(SA) stress that affects plant growth.Rice cultivation has been accepted as an important strategy for effective utilization of SA land if water is available for irrigation.Nevertheless,as a salt-sensitive plant,rice plants suffer severe SA-induced damage,which results in poor plant growth and grain yield.Various approaches have been employed to improve rice productivity in SA land.Among them,the priming technique has emerged as a powerful method for enhancing SA tolerance in rice plants.In this review,we summarized how SA stress damages rice plants,and then presented how priming treatment can mitigate such damage.

Land use effects on soil organic carbon, nitrogen and salinity in saline-alkaline wetland

Land-use and soil management affects soil organic carbon （SOC） pools, nitrogen, salinity and the depth distribution. The objective of this study was to estimate land-use effects on the distribution of SOC, labile fractions C, nitrogen （N） and salinity in saline-alkaline wetlands in the middle reaches of the Heihe River Basin. Three land-use types were selected： intact saline-alkaline meadow wetland, artificial shrubbery （planting Tamarix） and farmland （cultivated for 18 years） of soils previously under meadow wetland. SOC, easily oxidized carbon, microbial biomass carbon, total N, NO3--N and salinity concentrations were measured. The results show that SOC and labile fraction carbon contents decreased significantly with increasing soil depth in the three land-use wetlands. The labile fraction carbon contents in the topsoil （0-20cm） in cultivated soils were significantly higher than that in intact meadow wetland and artificial shrubbery soil. The aboveground biomass and soil permeability were the primary influencing factors on the contents of SOC and the labile carbon in the intact meadow wetland and artificial shrubbery soil, however, the farming practice was a factor in cultivated soil. Agricultural measures can effectively reduce the salinity contents; however, it caused a significant increase of NO 3--N concentrations which posed a threat to groundwater quality in the study area.

Denitrification Potential of Marsh Soils in Two Natural Saline-alkaline Wetlands

Little information is available on denitrification potential of marsh soils in natural saline-alkaline wetlands. The denitrification potentials of an open wetland in the floodplain(Erbaifangzi wetland) and a closed wetland(Fulaowenpao wetland) in backwater areas in Jilin Province of Northeast China were monitored by an anaerobic incubation at 30℃ for 25 days. Our results showed that the relative denitrification index(RDI) increased gradually with incubation time, and showed a rapid increase in the first 5 days of incubation. The RDI values declined quickly from surface soils to subsurface soils and then kept a small change in deeper soils along soil profiles over the incubation time. Denitrification proceeded much faster in the top 20 cm soils of open wetland than in the closed wetland, whereas no significant differences in RDI values were observed in deeper soils between both wetlands. The RDIs were significantly negatively correlated with bulk density and sand content, while a significantly positive correlation with clay content, soil organic matter, total nitrogen and phosphorous. The maximum net NO–3-N loss through denitrification in 1 m depth were higher in the open wetland than the closed wetland with higher soil pH values. Future research should be focused on understanding the influencing mechanisms of soil alkalinity.

Fisheries Management under Ecological Interdependence: The Case of European Hake and Blue Whiting Fishery

In mixed fisheries where there is an increased ecological interdependence between two or more target species, the possibilities of fishing these species must be determined jointly, since catches of one species will impact the natural growth not only of that species but of the others, as well. The objective of this paper is to develop a predator-prey model for two major species caught by the EU fishing fleet on European Union fishing grounds. The predator and prey’s population dynamics follow the Lotka-Volterra equation and are assumed to be logic-based, and a lineal interaction between the predator and prey populations is assumed. Optimal single owner multispecies fishery management is analysed, and the applied model is solved, obtaining the equilibrium value of biomasses, catches, and net benefits of the mixed fishery. The results show that the MSY of the predator is higher than that estimated by ICES, while MSY for prey is lower. The sensitivity analysis of the results reveals that the biomass levels of both species decrease as the discount rate increases, while catches increase.

Impacts of Sulfur and Microalgae Co-fertilization on Saline-alkaline Soil of Sunflower Field in Hetao Irrigation District

[Objectives]To evaluate the impacts of the elemental sulfur(S 0)and micro-algae(MA)co-fertilization on saline-alkaline soil of sunflower field in the Hetao Irrigation District(HID).[Methods]The greenhouse pot experiment was conducted with four treatments:control(CK),single S 0 fertilization(S),single MA fertilization(A),and S 0 and MA co-fertilization(SA)for comparing the selected soil properties and sunflower plant heights and weights in different treatments.[Results]The results showed that the mean soil organic matter(SOM)under the SA(25.08 g/kg)was significantly higher than that for the CK(20.59 g/kg),S(22.47 g/kg),and A(22.95 g/kg).The mean pH under the SA(7.75)was significantly lower than that for the CK(8.14),S(7.82),and A(7.96).The mean soil exchangeable Na+concentration under the SA was significantly lower than that for the S.The mean soil electrical conductivity(EC)under the SA was 9.76%lower than that for the S.The means of Cl-(1.22 g/kg)and SO 2-4(1.90 g/kg)in soil under the SA were lower than that for the S(1.30,2.06 g/kg)and A(1.31,1.97 g/kg),respectively.For plant height 3 at the late stage of plant growth,the mean plant height 3 under the SA(89.00 cm)was higher than that of the CK(69.60 cm)and A(74.33 cm).The total weights of the fresh sunflower heads,fresh stems,and dry seeds under the SA were higher than that for the CK,S,and A.[Conclusions]In conclusion,the S 0 and MA co-fertilization had positive effects on improving saline-alkaline soils,the soil under the S 0 and MA co-fertilization could be better conditions for promoting sunflower growth than that for the S,Z,and CK,and thereby the S 0 and MA co-fertilization could be a new idea to improve saline-alkaline soil in the cold and arid regions.

Sea Cucumber Fishery in Aurora, Philippines

This study was conducted to provide a preliminary assessment of the sea cucumber fishery in Aurora, Philippines. This was conducted from February to June 2013. All sea cucumber gatherers and traders, obtained through snowball sampling, in each identified sea cucumber fishery area in six coastal municipalities (Baler, Dipaculao, Dinalungan, Casiguran, Dilasag and Dingalan) were interviewed using a structured interview schedule and focused group discussions (FGD). Results revealed that gathering sea cucumbers were accomplished by handpicking, skin diving or compressor diving. A total of 15 commercial species were regularly gathered. Out of this, three species are of very high economic value (≥Php 4000/kg) (Holothuria nobilis, Holothuria scabra, and Actinopyga lecanora). The average number of kilograms harvested per hour per trip ranges from 0.21 (Holothuria fuscopunctata) to 2.71 (Holothuria scabra), while the average size of commonly gathered sea cucumber varies among species with Holothuria lecanora showed an average length (29.26 cm) greater than recorded 24 cm. Processing mainly involves washing, slicing, boiling, drying and packing. Processed sea cucumbers or trepan were sold to middlemen or direct buyers who usually offered higher prices (36.36% up to 69.20%) than the former. Problems encountered by sea cucumber gatherers and traders include a decline in total catch, a shift in area of collection from intertidal zones to deeper waters, an increase in the number of hours spent in finding and gathering sea cucumbers, the use of compressors in gathering, the decline of larger species and gathering of smaller sizes in huge amount, the absence of conservation program for sea cucumber, and the lenient implementation of government policies with regards to coastal resources management.

Ningxia:Fish-Farming on Saline-Alkaline Land

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Liaoyannuo developed by the Res Inst of Saline-alkaline Utilization of Liaoning Province

Liaoyannuo, a glutinous japonica type rice, had an average yield of 8.08 t / ha in two-year provincial trials, which is 12.6% higher than the CK Fengjin. Its average yield in two-year provincial production trials was 9.53 t/ha, 15.2% higher than the CKs Liaoyan 5 and Fengjin, respectively. Liayannuo is of moderate resistance or resistance to blast, bacterial blight of rice, sheath and culm blight of rice, rice aspergillus, response to fertility and endurance to saline and alkaline, drought and cold temperature.

Current status and countermeasures of facility fishery development

According to the"National Modern Facility Agriculture Construction Plan(2023-2030)released by the Ministry of Agriculture and Rural Affairs,the"Special Implementation Plan for Modern Facility Fisheries Construction"emphasizes the development of circular aquaculture,active expansion of green aquaculture space in facility fisheries,multi-channel development of food sources,comprehensive improvement of the quality,efficiency,and competitiveness of facility fisheries,ensuring stable and safe supply of aquatic products,and better meeting people's needs for high-quality aquatic products and beautiful aquatic ecological environment.Since the implementation of the 14th Five Year Plan for fisheries,facility fisheries have made significant progress.In order to thoroughly implement General Secretary Xi Jinping's important discourse on new quality productivity,conduct in-depth research on the current situation and existing problems of the fishery industry,and put forward suggestions to meet the requirements of high-quality development of the fishery industry in the new era.Therefore,it is crucial to continue practicing the"revitalization of aquatic seed industry"and"big food concept",take multiple measures to"demand food from rivers,lakes,and seas",and expand aquaculture space.Through research,it has been found that research in the field of facility based fisheries is still in its developmental stage.Further exploration is needed on the current status,breeding models,and experimental demonstrations of land-based facility based fisheries,in order to provide a basis for fisheries regulatory authorities to formulate the"15th Five Year Plan"for facility based fisheries.

The current research status of new quality productivity in China's fisheries

The literature reports mainly focus on 2023-2024,and the research hotspots are mostly productivity and new quality productivity.After analysis,research in the field of fisheries is still in its early stages.Among them,the facilities,intelligence,and"Blue granary"of marine fisheries need to be further strengthened to provide technical support for achieving the goal of"new quality productivity"in the fishing industry in the future.

Evaluation of Potential Fishery Productivity in Lihu Lake Based on GIS

[Objective] The paper was scientifically evaluate the potential fishery productivity of Lihu using GIS technology.[Method] The evaluation of potential fishery productivity in Lihu was based on GIS and AHP according to the characteristics of fisheries resources in Lihu Lake.The evaluation system included 3 sub-models including water quality,biodiversity and hydrological condition,which totally had 10 indexes.Judgment matrix was constructed based the advices of professors of fisheries resources,and the indicator’s weight were calculated by the process of AHP.The ranking distributing map of potential fishery productivity in Lihu was obtained by the model of raster analysis,raster calculator,spatial overlay and classification models of ARC/INFO.[Result] Potential fishery productivity of Lihu was divided into 4 grades in term of higher,high,general and low,and which covered 2.643 3,3.844 8,1.121 4 and 0.400 5 hm2,respectively.[Conclusion] The study provided theoretical basis for ecological reconstruction of Lihu Lake.

A Comprehensive Evaluation and Countermeasures of Fishery Development in China Based on Its Domestic Development and Foreign Trade

[Objective] The aim was to make a comprehensive evaluation and explore strategies on fishery development. [Method] Fishery development in China was analyzed and concerning evaluation system was established based on its development stage, international competiveness and exportation. In addition, a comprehensive evaluation was made on fishery and countermeasures were proposed considering from government, department of quality control, fishery guild, producing and processing enterprises. [Result] Although progresses have been made in fishery in China, some problems still exist, such as overdose of drug residues, overloading breeding, lower additional value of products, and fewer excellent and famous products. Hence, local governments should give much support to fishery and enhance competitiveness to improve the products in global market; departments of quality control should strengthen supervision and management on fishery products against technical trade barriers; fishery guilds or researching institutions should provide technical support for concerning breeding and processing which should be mainly relied on science and technology. [Conclusion] The research provided references for fishery development.

Effects of carbon sink fisheries ecosystems

Currently, due to the burning of fossil fuels and changes in land use patterns, a lot of CO2 （carbon dioxide） emissions into the air, the amount of CO2 in the air is extremely increased. According to the research CO2 is the main component of greenhouse gases and the main culprit of causing the greenhouse effect. The ocean is a huge repository of carbon, water can dissolve a large amount of CO2, in the ocean, a large number of plants and planktonic algae absorb CO2 to produce 02, It is a very large gathering place （sink）. At the same time, CO2 aggregation in the ocean seawater acidity increases, impact on fishery resources, sources and sinks of CO2 were discussed in the paper.

Spatio-temporal Evolution of Marine Fishery Industry Ecosystem Vulnerability in the Bohai Rim Region

The building of the ocean power strategy and the implementation of the blue agriculture plan urgently need to strengthen the sustainable development of marine fishery.Taking vulnerability as the starting point, this paper constructs the vulnerability index system of marine fishery industry ecosystem from the aspects of sensitivity and response capacity, and combines the entropy method with the Topsis to comprehensively analyze the spatio-temporal evolution characteristics of vulnerability of marine fishery industry ecosystem in the Bohai Rim Region from 2001 to 2015.The results show that: 1) In the time dimension, from 2001 to 2015, the vulnerability of the marine fishery industry ecosystem in the Bohai Rim Region shows a fluctuant and degressive trend;2) In the spatial dimension, the spatial distribution of the marine fishery industry ecosystem vulnerability in the Bohai Rim Region presents the gradient characteristics which shows high vulnerability in the east and low vulnerability in the west.According to the evolution track of the system’s vulnerability level, the vulnerability of the marine fishery industry ecosystem is divided into ‘declining’ and ‘stable’ types of evolutionary structures;3) The development of marine fishery in the Bohai Rim Region needs to be derived from the marine fishery’s ecological environment and the industrial development mode and structure, which can improve the marine environment remediation efforts, optimize the marine fishery industry structure, vigorously focus on pelagic fishery, and enhance the introduction of marine fishery’s science and technology talents, etc.Then, the marine fishery’s development in the Bohai Rim Region will be moving in the green, circular and sustainable direction.