Bacillus velezensis， as a new type of probiotic， is widely used in fields such as industrial fermentation and agricultural production. The functions of active substances produced by Bacillus velezensis， such as enzyme production and disease resistance etc， were introduced in detail. Its latest application status in livestock and aquaculture were reviewed. In view of the current problems existing in Bacillus velezensis， the future research focuses and development directions were prospected， which provided references for the in-depth research and practical application of Bacillus velezensis.

To determine the optimal sugar/fat ratio in the diet of Yellow River carp， on the premise of meeting its basic requirements for n-3 essential fatty acids （n-3 EFA）， a commercial feed with a conventional formula （sugar/fat ratio of 25/7） was used as the control group （T0）. Mixed soybean oil and linseed oil served as the fat source， and the sugar/fat ratios of the experimental diets were adjusted to 40/4 （T1）， 32/7 （T2） and 25/9 （T3） by modifying the addition amounts of carbohydrate and fat. The effects of different sugar/fat ratios on Yellow River carp were analyzed. The results showed that there were no significant differences in the morphological indices （hepatosomatic index and viscerosomatic index）， crude protein content in whole fish and muscle， serum cholesterol content and malondialdehyde content among different dietary groups. However， the specific growth rate and weight gain rate significantly increased with the elevation of dietary sugar/fat ratio. The serum glucose level in T2 treatment and the serum insulin content in T1 treatment were significantly higher than those in T0 treatment. The activities of hepatic glucokinase and 6-phosphofructokinase-1 in T1 treatment were significantly higher than those in T3 treatment. Additionally， the contents of serum triglyceride， high-density lipoprotein cholesterol， as well as hepatic triglyceride and non-esterified fatty acids significantly decreased as the sugar/fat ratio increased. Regarding hepatic antioxidant capacity， the total antioxidant capacity in T1~T3 treatments was significantly higher than that in T0 treatment. In terms of muscle fatty acid composition， the levels of eicosatrienoic acid， docosahexaenoic acid， n-6 polyunsaturated fatty acids and total polyunsaturated fatty acids in the muscle and liver of Yellow River carp in T1~T3 treatments were significantly higher than those in T0 treatment. The expression levels of Δ6 fad-β and elovl5-α in the liver of Yellow River carp in T0 and T1 treatments were significantly higher than those in T2 treatment， and the hepatic Δ6fad-α expression level in T1 treatment was significantly higher than that in T0 group treatment. These findings indicated that a dietary sugar/fat ratio of 40/4 （T1） was more conducive to the synthesis of highly unsaturated fatty acids in the fish liver. In conclusion， when the essential fatty acid content in the diet was sufficient， the utilization rate of high sugar/fat ratio diets could be improved， which in turn enhanced hepatic glucose and lipid metabolism， promoted the growth of Yellow River carp， and improved the quality of muscle fatty acids.

To preliminarily explore the effects of dietary supplementation with Cetobacterium products on the growth performance indicators， liver health and gut microbiota of pond cultured bighead carp （Aristichthys nobilis）， bighead carp were randomly divided into control and Cetobacterium products supplemented treatments， and a 8-weeks trial was carried out. The results showed that dietary supplementation with 0.2 kg·t^-1Cetobacterium products significantly increased the carcass ratio of bighead carp， while significantly decreased the viscerosomatic， hepatosomatic and intestinosomatic indexes， and also significantly enhanced the activities of intestinal lipase and cellulose， and reduced hepatic lipid deposition. In addition， feeding Cetobacterium products significantly increased the abundance of beneficial bacteria at both phylum and genus levels in the gut， and altered the composition and structure of gut microbiota in bighead carp. Above results indicated that Cetobacterium products could improve the growth performance， enhance digestive enzyme activities， promote liver health， and optimize the gut microbiota structure of bighead carp.

Siniperca chuatsi is an important high-quality freshwater aquaculture species in China. As a naturally carnivorous and highly predatory fish， it primarily feeds on live bait. Artificial domestication methods to alter the dietary habits of carnivorous fish can reduce farming costs and decrease reliance on natural resources. To investigate the effects of replacing live bait with compound feed on the growth performance， digestive function and antioxidant capacity of S. chuatsi， juvenile S. chuatsi （23.17±0.75 g） were divided into 3 groups： compound feed （F group）， live bait （B group）， a mixed diet of one meal of compound feed and one meal of live bait （M group）. After 3 months of farming， growth performance indicators were measured， digestive and antioxidant enzyme activities were assessed， and the microstructures of the gastrointestinal tract were observed. The results showed that the body weight and body length of F group were significantly higher than those of M group， and the feed conversion ratio of F group was significantly lower than that of B group. However， no significant differences were observed in total length， body height， condition factor， hepatosomatic index， and viscerosomatic index among the 3 groups. The superoxide dismutase activity in F and M groups was significantly higher than that in B group， while the catalase activity in B and M groups was significantly higher than that in F group. The reduced glutathione content and glutathione peroxidase activity in F group were significantly higher than those in M group， and the total antioxidant capacity in B group was significantly higher than that in M group. No significant differences were observed in malondialdehyde content among the 3 groups. In gastric tissues， the trypsin activity in M group was significantly lower than that in B group， while the amylase activity in F group was significantly higher than that in B group. No significant differences were observed in gastric lipase activity and intestinal digestive enzyme activities among the 3 groups. The intestinal villus height in the F group was significantly greater than that in B and M groups. Compared to B group， the intestinal villi in F and M groups were sparser， with increased inter-villus spaces in the intestinal lumen. In conclusion， domesticated S. chuatsi fed with compound feed showed no adverse effects on growth performance， although M group was less effective than the other 2 groups. The fish adapted to the compound feed by enhancing amylase activity， increasing specific antioxidant enzyme activities， and improving intestinal villus height and inter-villus spaces. Above results provided theoretical basis for the large-scale farming of S. chuatsi using formulated feed and further optimization of feed composition.

To explore the impact of different planting densities， stocking densities and feeding frequencies on performance of Micropterus salmoides and water quality in fish-vegetable symbiosis，the plant densities were set at 32 （a₁） ，46 （a₂） ，60 plants·m^-2（a₃） ， the stocking densities were set at 8 （b₁），13 （b₂），18 kg·m^-3 （b₃）， the feeding frequency were set at 1 （c₁） ，2（c₂） ，3 times·d^-1 （c₃） ，respectively. The optimal combination of stocking density and feeding frequency were screened through the combined treatment of 3 factors and 3 levels. The results showed that planting density had significant effect on weight gain， weight gain rate， specific growth rate and feed coefficient； feeding frequency had significant effect on weight gain， feeding frequency had significant effect on the crude protein and crude fat content in muscle. The contents of ammonia nitrogen， nitrite nitrogen， total nitrogen and total phosphorus in each treatment group increased significantly over time， peaking on the 7^th day. The ammonia nitrogen， nitrite nitrogen and total nitrogen were stable after 37 d， while the total phosphorus stabilized after 25 d. The water quality indexes of a₂b₁c₂ and a₂b₂c₃ treatments were better than those of the other treatments. In this aquaponics system， the lettuce planting density of 6 plants·m^-2， the largemouth bass stocking density of 13 kg·m^-3 and the feeding frequency of 3 times·d^-1 could yield the optimal performance in terms of growth and muscle quality of largemouth bass， and water quality regulation effect. Above results provided a theoretical reference for the planting and stocking in aquaponics system.

To study the effects of dietary supplementation with coenzyme Q10 （CoQ10） protein and taurine replacing on growth performance and anti-stress resistance in Litopenaeus vannamei， a 56 d breeding experiment was carried out. The experiment set 7 treatments， including fish meal feed as the control （CK）， 5% CoQ10 protein （Q1）， 5% CoQ10 protein+0.3% taurine （Q2）， 5% CoQ10 protein+0.6% taurine （Q3）， 10% CoQ10 protein （Q4）， 10% CoQ10 protein+0.3% taurine （Q5） and 10% CoQ10 protein+0.6% taurine （Q6）. The results showed that the specific growth rate of Q3 treatment was significantly higher than those of other treatment， and its feed coefficient was significantly lower. After transport stress， the survival rate of CoQ10 protein treatments was higher than that of CK， but no significant differences were observed among treatments， and the treatments supplemented taurine exhibited higher plasma superoxide dismutase activity and total antioxidant capacity compared to CK， while malondialdehyde content was significantly lower. In conclusion， under this experimental conditions， substituting fish meal with 5% CoQ10 protein and 0.6% taurine in the diet could improve the growth performance and stress resistance of L. vannamei. Above results revealed the potential of coenzyme Q10 protein and taurine in enhancing the efficiency and sustainable development of shrimp farming， which provided scientific basis for the development of low-fish meal feed for L. vannamei.

Current global agricultural development faces challenges such as climate change and food security， making it particularly important to strengthen international cooperation in agricultural science and technology. As a major nation in agricultural science and technology， it is imperative for China to systematically sort out its international cooperation practices. Based on 5 institutional mechanisms including intergovernmental cooperation， joint research and development， demonstration bases， cooperative parks， and market-led models， this study selected 5 typical case models for comparative analysis. The results found that China’s international agricultural science and technology cooperation effectively drived the transformation and capacity building of agricultural industries in partner countries while ensuring project sustainability through technological innovation， technology adaptation， synergy between livelihoods and ecology， regional radiation， and institutional innovation. Research recommendations suggested that future efforts should strengthen top-level design， innovate market-oriented cooperation models， deepen the integration of industry， academia， and research， and prioritize local talent cultivation to enhance cooperation efficiency. These measures provided a Chinese solution for building a community with a shared future in the agricultural sector.

Under the backdrop of the ‘dual carbon’ strategy， it is necessary to analysis the regional differences in China’s livestock industry’s green total factor productivity and testing its convergence， which can provide empirical evidence for achieving regional green and coordinated development in the livestock industry. The panel statistical data from 31 provincial-level administrative units in China from 2006 to 2023 was selected. By constructing a Super-SBM model based on environmental negative outputs and combining it with the global-Malmquist-Luenberger （GML） index to measure the green total factor productivity （GTFP） of the livestock industry， the Dagum Gini coefficient was empirically analyzed， and its regional differentiation characteristics and formation mechanisms were further employed. Finally， the σ convergence and β convergence models were introduced to test its convergence patterns. The results indicated， during the study period， the average value of China’s GTFP index for the livestock industry was 0.979， showing an overall negative growth trend. The key influencing factor was green technological progress， which exhibited significant regional non-equilibrium. The overall differences in GTFP in the livestock industry exhibited a fluctuating trend of first narrowing and then widening. In 2023， the overall Gini coefficient rose to a historical peak of 0.136， with inter-regional differences being the primary source of spatial disparities. The σ convergence of the GTFP of the livestock industry was not significant， but it exhibited absolute β convergence and conditional β convergence characteristics. Therefore， the government should focus on enhancing green technological progress， strengthening inter-provincial capital and technology flows， and promoting regional coordinated development.

Rice cellulose synthase supergene family is composed of CesA （cellulose synthase） and Csl （cellulose synthase-like protein）. In order to understand the sequence characteristics and expression characteristics of the members of the family， and explore their functions， bioinformatics methods were used to identify OsCesA/Csl genes in the whole rice genome. Their physical and chemical properties， conserved motifs， gene structure， systematic evolution， cis-acting elements， chromosome mapping and collinearity were analyzed. Their expression in different tissues and different plant hormone treatments were analyzed based on transcriptome data. The results showed that a total of 22 members of OsCesA/Csl family were identified in rice genome， and the length of gene coding sequence （CDS） was 774~3 648 bp， protein molecular weight was 28.55~132.16 kD， isoelectric point was 6.09~9.62， and average hydrophilic coefficient was -0.339~0.750. The subcellular localization of 22 members was on cell membrane or Golgi apparatus. Phylogenetic evolution divided 22 members into 2 categories： OsCesA and OsCsl， each containing 11 members. The family members were distributed on 11 chromosomes except chromosome 11. There were 2 sets of tandem repeat genes in rice， and there was better collinearity between rice and maize. OsCesA/Csl members had different tissue expression patterns， and each member responded to jasmonic acid， abscisic acid， gibberellin and auxin treatment in different degrees. Above results laid a foundation for further exploring the specific function of OsCesA/Csl gene family in the growth and development of rice.

In order to investigate the effects of proline （Pro） application on seedling growth of wheat under drought stress， wheat variety Bainong 207 was used as experimental material， and 4 treatments were set， including water （CK）， 20% PEG-6000 solution （PEG）， 20 mmol·L^-1 proline （PRO） and 20% PEG-6000 solution+20 mmol·L^-1 proline （PFG+PRO）. The physiological mechanism of drought resistance in wheat treated with proline at seedling stage were analyzed. The results showed that， before drought stress， there were no significant differences in SPAD value and the contents of malondialdehyde （MDA）， soluble sugar （SS） and Pro among 4 treatments. After drought stress， compared with CK， SPAD value of PEG treatment was decreased， the contents of MDA， SS， Pro were increased， and relative expressions of SOD， POD and P5CS genes increased， seedling height， stem and leaf fresh weight， stem and leaf dry weight and root dry weight in PEG treatment were significantly lower， and root to shoot ratio was significantly higher. Compared with PEG treatment， the SPAD value and the contents of SS， Pro were significantly increased， MDA content significantly decreased. After 1 d of drought stress， the relative expressions of SOD， POD and CAT genes in PEG+PRO treatment were significantly higher than those in PEG treatment. After 2 d of drought stress， the relative expressions of LEA and P5CS genes were significantly higher than those in PEG treatment. After drought stress， the plant height， stem and leaf dry weight of PEG+Pro treatment were significantly increased by 11.64% and 12.96% compared with PEG treatment. In conclusion， external application of Pro at seedling stage could reduce MDA content in leaves， increase SPAD value， the contents of SS， Pro and the relative expression levels of stress-related genes including SOD， POD， CAT， LEA and P5CS， which could improve drought resistance of wheat and lay a foundation for normal growth and development of wheat in the following stage.

In order to analyze the nitrogen deficiency tolerance of cotton germplasm resources， in pots with low nitrogen （15 g·m^-2） and normal nitrogen （45 g·m^-2） conditions under a rainproof shelter at the seedling stage， root dry weight， shoot dry weight， total dry weight， ratio of root to shoot and chlorophyll value of 419 upland cotton germplasm resources were measured， and their nitrogen deficiency tolerance indexes were calculated. Through correlation analysis， principal component analysis and membership function analysis， the comprehensive evaluation of nitrogen deficiency tolerance of 419 cotton germplasm resources was conducted. The results showed that， under low nitrogen stress， there was extremely significantly negative correlation between the nitrogen resistance index in shoot dry weight and in ratio of root to shoot of cotton seedlings. However， other traits showed significantly positive correlations or extremely significantly positive correlations. Principal component analysis classified 5 indexes into 3 principal components， whose cumulative variance contribution rate was 98.590%. D-values were calculated based on the weights of these 3 principal components. Then the 419 germplasms were divided into 4 grades and 10 nitrogen deficiency tolerant germplasms were screened. Furthermore， through stepwise regression analysis，a regression equation was established as D=-0.123+0.167X_RDWNRI+0.252X_TDWNRI+0.132X_SPADNRI （X_RDWNRI， X_TDWNRI and X_SPADNRI were nitrogen resistance indexes of root dry weight， total dry weight and chlorophyll value）. Above results laid foundation for further mining of nitrogen deficiency tolerant genes and improving nitrogen deficiency tolerance of cotton.

To cultivate new varieties of eggplant facilities and explore good germplasm resources of eggplants， 30 eggplant lines from different genetic sources were used as the materials and planted in solar greenhouse. Important phenotypic traits in facility cultivation were investigated， such as plant height， main stem thickness and so on， and genetic diversity was analyzed. The results showed that there was different degrees of variation among the 14 personality traits measured， with coefficient of variation ranging from 11.387% to 55.014%， the coefficient of variation of fruit flesh color was the smallest， and the coefficient of variation of fruit type was the largest， indicating that eggplants had rich fruit type variation and strong breeding potential. The correlation analysis showed that there was significant positive correlation between plant height and single fruit weight， plant height and low temperature tolerance， main stem diameter and low temperature tolerance， leaf length and leaf width， low temperature tolerance and single fruit weight， and the number of fruits per plant and single plant yield. The correlation between other traits did not reach a significant level. Principal component analysis was used to classify 14 personality traits into 4 principal components， with a cumulated contribution rate of 92.625%， which basically contained most of the information of eggplant phenotypic traits and could be used as comprehensive indicator of eggplant phenotypic traits. 30 eggplant lines were divided into 4 groups at a European distance of 10. After comprehensive comparative analysis， it was found that the Class Ⅲ performed well and could be used as a parental trial combination. Above results provided reference for future breeding practices.

Aiming at the problems of low accuracy of pig image segmentation and insufficient real-time segmentation in complex scenes， an algorithm for segmentation modeling of group pig instances based on improved YOLO v8n-seg was proposed. Based on YOLO v8n-seg， GhostConv was firstly introduced into the C2f module to reduce the computational complexity of the model. Secondly， attention mechanisms such as spatial group-wise enhancement， involution， and multidimensional collaborative attention were added at different locations of the network structure for enhancing the model's for feature extraction and fusion. Finally， wise IoU （WIoU） was chosen as a new loss function to speed up the convergence of the model and improve the overall performance of the detector. The results showed that， compared to the original model， the improved model reduced the number of parameters by 0.39 M. In terms of detection accuracy， the precision was improved by 3.7 percentage point， the recall by 4.8 percent point， the mean average precision of intersection over union threshold value 50% and 50% to 95% by 4.6 and 7.6 percent point， respectively， and the frames-per-second by 5.2， which showed good performance. A large improvement in both accuracy and speed were achieved by improving the YOLO v8n-seg， especially for the problem of reduced segmentation accuracy due to pig adhesion and mild occlusion in group rearing scenarios， the model showed excellent performance and was able to accurately segment individual pigs in a group， which provided a strong support for practical production applications.

In order to solve the problems of low open cassava rate and high cassava injury rate in the working process of the existing cassava harvester， a 4UMS-1000 cassava harvester was developed， and the structural design and analysis of key components such as long and short excavator shovel， cassava soil separation device and collection device were carried out， and its field operation performance was studied. The Box-Benhnken experiment method was used to carry out a three-factor three-level orthogonal experiment， and the quadratic multiple regression model and response surface were established， and the influence of the experiment factors on the evaluation index was further analyzed. The results showed that the optimum working parameters were the excavation shovel angle 28°， the tool forward speed 0.56 m·s^-1 and the excavation shovel depth 187 mm；under this condition the cassava digging rate was 97%， and the cassava injury rate was 3.3%. 5 replicate experiments were carried out on the optimal working parameters， and the results showed that the relative error between the open cassava rate and the injured cassava rate and the theoretical value was within 2%， which met the requirements of cassava harvesting operation. Above results provided reference for the subsequent development of cassava harvesting machinery.

Oil salsa bean tubers grow underground， small particles， beans and soil separation difficulties， the northeast region is mostly black clay soil， in the initial sieving is easy to lead to soil deposition in the sieve holes to produce a clogging phenomenon， affecting the threshing efficiency of the oil salsa bean harvester and the threshing quality. Aiming at the problems of easy clogging and low threshing rate of the equipment during the harvesting of oil soybean in the northeast region， a composite sieving oil soybean harvester was developed. The key components of the device， conveyor chain device and drum threshing device， were optimised. The Box-Behnken method was used to optimise the conveyor chain device to investigate the effects of different factors on the removal rate and the leakage rate. The results showed that the optimal working parameters of the mesh chain were vibration height 20 mm， the linear speed of mesh chain 0.9 m·s^-1， and the angle of mesh chain 46°. Under these conditions， the removal rate and leakage rate of the primary sieve were 66.83% and 0.55%， respectively. The tooth shape of the drum threshing device indicated that when the tooth shape was a mixture of bowed and pegged teeth，the effect was good， and the removal rate and the breakage rate were 99.33% and 1.10%， respectively. The modal analysis was carried out using Ansys software showed that the device was safe. Above results provided reference for the design of oil salsa bean harvester and promoted the development of oil salsa bean cultivation towards industrialisation.

Weeds in farmland are one of the important factors restricting crop production， which seriously affect the yield and quality of crops. Improving the control level of grass damage is of great significance for stabilizing and developing crop production. Chemical control of weeds is currently the main method utilized in agricultural production， however， the improper use of herbicides often causes harm to crops. Planting herbicide resistant crops is the most economically effective way to control weeds. The main types and mechanism of herbicides currently used in crops were reviewed， the research progress of herbicide resistant materials were outlined， and the major types and mutation sites of resistant weeds worldwide were analyzed. Finally， the more potential target sites for herbicides should be explored， and the emerging gene editing and other technologies should breed more new herbicide resistant germplasm， which should accelerate the cultivation of herbicide resistant varieties.

Jujube witches’ broom （JWB）， caused by Candidatus Phytoplasma ziziphi， is currently the most devastating jujube disease. A novel non-classical secretory protein， ncSP35， was identified from the JWB phytoplasma through bioinformatics analysis combined with an Escherichia coli-based alkaline phosphatase reporter system. Transient expression of ncSP35 in Nicotiana benthamiana using a potato virus X-based expression vector demonstrated that the protein suppressed Bax-triggered hypersensitive response （HR） and hydrogen peroxide accumulation， and interfered with plant growth and development. Deletion and site-directed mutagenesis analyses revealed that the central region （amino acid residues 37~71） and the polar amino acid cluster HKKENK?2 of ncSP35 were critical for HR suppression， while the C-terminal 18 amino acid residues were essential for interfering with plant growth and development. Subcellular localization analysis showed that ncSP35 formed abundant aggregates in the cytoplasm and inhibited the nuclear localization of histone H2B， causing H2B to also form aggregates in the cytoplasm. Yeast two-hybrid， co-immunoprecipitation and luciferase complementation assays confirmed the specific interaction between ncSP35 and jujube ZjH2B. Above results provided new molecular insights for JWB pathogenesis.

Agricultural synthetic biology integrates engineering and life sciences， which has evolved from single-gene editing to systematic design. Key technologies include CRISPR-Cas optimization， AI design platforms， synthetic microbial technologies and crop chassis modification. The application of these technologies has driven the development of new agricultural production paradigms and promoted technological innovations in such areas as nutrient-enhanced crops， environmentally friendly inputs， stress-resistant crops and low-carbon cycling technologies. At the same time， it faces multi-dimensional risks： in terms of biosecurity， there are risks of off-target effects in gene editing， pathogen modification and biological weapons， laboratory error； in terms of ecological security， there are impacts on biodiversity， disturbances to ecosystem functions； in terms of social ethics， there are controversies over creating life and the essence of life， uncertainties regarding food safety and health impacts， and controversies over the compatibility of organic agriculture with synthetic biology； in terms of economic effect， there are risks of technology and market monopoly， impacts of industrial chain restructuring and integration on employment， the structure and functions of agricultural systems. For above reasons， countries around the world have attached great importance to building public risk prevention and control systems， forming three main models： product-based regulatory models process-based regulatory models， and hybrid models. In the future， the contradiction between the rapid iteration of technology and the lag in policy supervision is the most severe challenge facing agricultural synthetic biology. It is necessary to follow the principles of full life cycle management， prevention first， and scientific assessment， and support global food security and environmental sustainable development by improving policies and governance systems and adhering to the path of responsible innovation.

In order to examine the impact of ryegrass treated with urea on ammonia volatilization in paddy soil， the southern rice-green manure （ryegrass） rotation model was used as a research subject for a pot experiment， and 5 dosing ratios were set up： urea alone （CF），25% ryegrass+75% urea （25%RG），50% ryegrass+50% urea （50%RG），75% ryegrass+25% urea （75%RG） and ryegrass alone （100%RG）， with all treatments applying nitrogen at a rate of 100 mg N?kg^-1 air-dried soil. Ammonia volatilization rate， rice yield and soil environmental indicators were monitored for the rice season under different treatments. The results showed that the ammonia volatilization rate of all treatments increased rapidly after urea application， and the peak ammonia volatilization emission decreased with the increase of the proportion of urea replaced by ryegrass. The magnitude of cumulative ammonia volatilization was in the following order： CF>25%RG>50%RG>75%RG>100%RG， with the maximum value of 30.53 mg?m^-2 and the minimum value of 22.07 mg?m^-2. Compared with CF treatment， the cumulative ammonia volatilizations of ryegrass return to field treatments were reduced by 4.8%， 17.2%， 20.7% and 27.7%， respectively， with the emission factor of 50%RG （ammonia emission intensity per unit of N fertilizer input） was significantly lower （P<0.05） than that of CF. Rice yields of the 25%RG and 50%RG treatments were not significantly different from that of CF， but ammonia volatilization emission intensity of the 50%RG was the lowest and differed significantly （P<0.05） from the other treatments. Soil temperature， pH and ammonium and nitrate nitrogen contents significantly （P<0.05） affected the ammonia volatilization rate from paddy fields. In conclusion， the 50%RG treatment could effectively slow down the loss of ammonia volatilization from paddy soil while taking into account the rice yield， which was of great significance in reducing nitrogen loss from paddy soil and protecting the ecological environment.

The excavation of highway projects causes a large area of exposed rocky slopes which is the main cause of soil erosion. In order to explore the role played by eco-bags in ecological protection of highway slopes， the highway slopes in the ecologically fragile area of forest and grass interspersed in Northeast Inner Mongolia were selected as the research object， and a combination of field investigation and indoor experiment was adopted to analyse the soil， vegetation index and root characteristics of the eco-bags. The results showed that the effect of slope direction on soil physicochemical properties （except for bulk density and total nitrogen content） were negative>positive>control slopes， in which the total potassium content of the negative slopes varied most significantly， which was 18% and 26% higher than that of the positive slopes and control slopes， respectively； the slope direction was negative>positive>control slopes in terms of the height， cover and biomass of the plant plants， and the total length of the root system of the negative slope was 30% and 38% higher than that of the positive slope and control slope， respectively. The principal component analysis showed that the composite scores of shady slope， sunny slope and control slope reached 46.16，-13.00 and -33.15， respectively. Comparison between the original exposed rocky slope and the slope protected by eco-bags revealed that the soil nutrients and vegetation growth of slopes protected by eco-bags were better， while the ecological environment of the original ecological slopes was more fragile， and the ecological protection of exposed rocky slopes in the fragile areas should be strengthened. The ecological environment of the original slopes is more fragile. The results provided a theoretical basis for further investigation of the impact of ecological bags on highway slopes.

To disclose the extent of coupling coordination among cultivated land production， living and ecological spaces as well as their spatial distribution characteristics，by constructing a comprehensive evaluation index of cultivated land “production-living-ecological” space， the index weight was determined by entropy weight method， and the coupling degree and coupling coordination degree models were used to calculate the coupling degree and coupling coordination degree of cultivated land “production-living-ecological” space in Gansu province from 2013 to 2022， and the trend characteristics and reasons for their changes were analyzed. Using ArcGis， the coupling coordinated degree distribution maps of cultivated land “production-living-ecological” space in 14 cities and states of Gansu province in 2013， 2016， 2019 and 2022 were drawn， and the spatial distribution characteristics were studied. The results showed that the comprehensive development level of cultivated land “production-living-ecological” space was different greatly， and the comprehensive development level of production space showed an “U” shape， and the development level rose steadily after declining. The comprehensive development level of living space showed a “L” shape， and the development level showed a high opening and low moving trend. The comprehensive development level of ecological space showed a “M” shape， and the development level showed get lower and lower. From the perspective of temporal evolution， the “production-living-ecological” space of cultivated land was in a low coordinated development state as a whole， the coupling coordination degree generally presented a “V” shape development from 2013 to 2022， the highest coupling coordination degree was 0.800 2 in 2013， and the lowest coupling coordination degree was 0.534 6 in 2015， coordinated development was achieved in 2013 to 2014 and 2019 to 2022， of which 2013 was a high quality coordination development， and 2015 to 2018 was on the borderline dysregulation development. In terms of spatial pattern， there were obvious regional differences in the coupling coordination state， with most of the central and western part of Gansu province was on the borderline dysregulation development， the southeast was dominated by “huddling” primary dysregulation. Above results suggested that the distribution pattern of cultivated land resources should be considered， and on the basis of different cultivated land control measures to promote the coupling and coordinated development of the “production-living-ecological” space of cultivated land from setting the range of seed and harvest subsidies according to the actual situation， moderately mechanized cultivated land， diversified crop planting， and improving the level of social services.

In order to clarify the influence of flat single-axis low-pile tracking photovoltaic panels on the spatial distribution characteristics of soil nutrients in photovoltaic power stations in sandy areas， the soil under flat single-axis low-pile tracking photovoltaic panels in the vegetation natural restoration area of photovoltaic power stations in typical sandy areas of western Inner Mongolia was taken as the research object. The photovoltaic panels were divided into 4 positions： inter-panel （IP）， front-panel （FP）， back-panel （BP） and under-panel （UP）. At the same time， 5 soil depths of 0 to 10， 10 to 20， 20 to 40， 40 to 60 and 60 to 100 cm were set at each position. The bare sandy land without any photovoltaic measures in the photovoltaic power station was used as the control （CK）. Through correlation analysis and one-way analysis of variance， the horizontal and vertical distribution characteristics of soil nutrients under the flat uniaxial low-pile tracking photovoltaic panel were explored， and the principal component analysis was further used to evaluate the soil quality at different locations in the field.The results showed that the construction of tracking photovoltaic panels would reduce the atmospheric temperature and atmospheric humidity in the photovoltaic field. The soil moisture and soil bulk density at different positions of the electric board showed a law of increasing with the increase of soil depth. The construction of tracking photovoltaic panels would increase the content of soil nutrients. The contents of soil available nitrogen， organic matter and available potassium decreased with the increase of soil depth. The content of available phosphorus changed little and fluctuates between different depths. The soil quality of the tracking photovoltaic panel area was higher than that of the CK position， among which the soil quality of IP， FP and RP positions was better， and the soil quality of UP and CK positions was poor，which showed that the construction and operation of tracking photovoltaic panels in sand area improved the soil quality in the field area. Above results provided theoretical support for the ecological restoration of photovoltaic power stations in sandy areas.

CRISPR/Cas9， as a powerful gene editing tool， has been widely applied in porcine genetic improvement. However， editing a single gene does not meet the requirements for simultaneous multi-trait enhancement. To establish a multi-gene editing system in porcine embryonic fibroblasts （PEFs） and generate embryos with concurrent modifications in MSTN， pAPN and CD163 genes using the CRISPR/Cas9 system， based on the functional domains of porcine CD163， MSTN and pAPN proteins， exon 1 of MSTN， exon 7 of CD163， and exon 2 of pAPN were selected as target regions. 2 pairs of sgRNAs were designed and cloned into the pX330 backbone vector， and electroporated into PEF cells to select the sgRNA with the higher editing efficiency for each gene. Homologous recombination was employed to assemble the individual sgRNA expression cassettes for CD163， MSTN and pAPN into an integrated tandem expression system， which was transformed into Fast-T1 competent cells and verified by Sanger sequencing. The three-gene knockout vector was then electroporated into PEF cells， and selection was performed with 2.5 μg·mL^-1 puromycin. Single-cell clones were isolated， followed by PCR amplification and Sanger sequencing to verify the target sequences of MSTN， CD163 and pAPN in each clone. The results indicated that the editing efficiency of sgRNA1 was higher than that of sgRNA2 for CD163， MSTN and pAPN genes， and the sgRNA1 with higher efficiency was selected for the construction of integrated plasmid. Plasmid sequencing confirmed that the three sgRNA expression cassettes were successfully integrated into the pX330 backbone vector. Among 45 single-cell clones transfected with the three-gene editing vector， the mutation rates for MSTN， pAPN and CD163 were 62%， 26% and 11%， respectively， with 4 clones achieving simultaneous editing of all three genes （efficiency of 8.9%）. Furthermore， embryos produced via somatic cell nuclear transfer （SCNT） using the edited cells showed no significant differences in cell fusion rate， cleavage rate， or blastocyst formation rate compared to embryos derived from non-edited cells. Sequencing results demonstrated that the embryonic target modifications were consistent with those in the somatic cells. In conclusion， PEF cells and embryos were successfully generated with concurrent modifications in the porcine MSTN， pAPN and CD163 genes using CRISPR/Cas9 technology， which laid the foundation and provided reference for the production of multi-gene edited cloned pigs.

In order to evaluate the feasibility of high-definition X-ray fluorescence spectrometry （HDXRF） in the rapid analysis and investigation of excessive Cd in paddy fields， the national standard soil materials and Cd-exceeding paddy fields in central Guizhou was used as the research objects. The relative error （RE） and relative standard deviation （RSD） were used to evaluate the accuracy of HDXRF method for the determination of Cd content in soil. The difference between HDXRF method and （inductively coupled plasma source mass spectrometer ICP-MS）method for the determination of Cd content in paddy soil was studied， and the effects of sample preparation and test conditions such as soil moisture， sieve particle size and detection time on the determination of Cd content in paddy soil by HDXRF method were analyzed. The results showed that the lower limit of determination of Cd in soil by HDXRF method was 0.254 mg·kg^-1， which was lower than the minimum screening value （0.3 mg·kg^-1） of Cd in Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard （Trial） （GB 15618—2018）. When the soil Cd content was higher than the lower limit of determination （0.254 mg·kg^-1）， the accuracy and precision of HDXRF method for the determination of soil Cd content were higher （<10%）. There was no significant difference in Cd content in paddy soil by HDXRF method and ICP-MS method. The fitting equation of soil Cd content determined by these 2 methods was y=0.981x+0.006 （R²=0.998）. With the increase of soil moisture content， the RE and RSD of Cd content in paddy soil by HDXRF method showed an increasing trend. There was no significant difference in Cd content between 2.5% （air-dried） soil moisture content and 0% （oven-dried） soil moisture content. With the decrease of soil sieve particle size， the RE and RSD of Cd content in paddy soil by HDXRF method decreased. When the sieve particle size was 0.15 mm， the variation range of Cd content in paddy soil by HDXRF method was the smallest， and both RE and RSD were less than 10%. With the increase of detection time， the RE and RSD of Cd content in paddy soil by HDXRF method showed a decreasing trend. When the detection time was 10 min， theRE and RSD of Cd content in paddy soil by HDXRF method were less than 10%. In summary， HDXRF method was suitable for rapid analysis and investigation of Cd exceeding standard in paddy fields. The suitable sample preparation and test conditions were soil moisture content of 2.5%， sieve particle size of 0.15 mm and detection time of 10 min.