The safe supply of edible oil plays an important role in maintaining national food security and promoting people’s nutrition and health. The key to promoting the development of the oil industry lies in scientific and technological innovation. Analyzing the development trend of the oil discipline and examining the evolution of key research areas can help to promote technological innovation in the oil industry and ensure the safe supply of oil.This paper adopted a combination of qualitative and quantitative methods. While qualitatively analyzing the development trend of oil discipline and its eight key research fields， it also analyzed the research layout of each field in the world based on the metrological method of information science， clarified the international research hotspots.Facing the frontier of agricultural science and technology in the world， the major needs of the country， the main battlefield of modern agricultural construction， and the life and health of the people， this paper put forward relevant suggestions on the development of oil discipline.
Flowering is the important stage for plant to produce sexual organs. Floral integrators integrate the environmental and endogenous signals to ultimately activate floral transition at the appropriate time， enabling the plants to reproductive success. Although genes floral integrators （FT， SOC1 and LFY） have been cloned in cotton， their evolutionary relationship in tetraploid cotton remains unknown. In this study， the homologous of flowering integrators were identified through comparing the released cotton genomes. The results revealed that FT and LFY were evolutionally conserved among diploid and tetraploid cottons， while SOC1 displayed sequence diversity. Specifically， cotton flowering integrators displayed unified expression in leaf and shoot apical meristem with a gradual increase during seedling development. The unreported sequences GhLFY-2， GhFT-2 and GhSOC1-5 were cloned and overexpressed in Arabidopsis， resulting in conserved function of promoting floral transition. However， the regulatory mechanism between the flowering integrators was peculiar in cotton. There was a conserved GhFT-2/GhSOC1-5/GhLFY-2 linear regulatory pathway and a direct pathway in which GhFT-1 and GhSOC1-1 regulate GhAP1 independent of GhLFY. The diversity of flowering time regulation might associate with adaptation of cotton to the environment.
To increase and optimize the Fagopyrum esculentum Moench germplasm resources in Shanxi， and screen the varieties of high-yield and high-quality， 51 varieties introduced from foreign were used as materials. 11 agronomic traits were determined and evaluated by the diversity analysis， grey correlation analysis， principal component analysis and comprehensive D value. The results indicated that the abundant variations were found in 51 varieties. And the coefficients of variation of the 11 agronomic traits were ranged from 9.562% to 115.337%， which the coefficients of variation of grain number per plant， seed weight per plant， yield， number of first-order lateral branches， main stem section number， plant height， stem diameter and 1 000-grain weight were more than 20%. The principal component analysis showed that the cumulative contribution rate of four principal components was 83.247%. Correlation analysis indicated that the yield was significantly positively correlated with plant height， stem diameter， grain yield per plant， and grain number per plant， which was the highest correlation coefficient with grain number per plant. The comprehensive results of various analyses showed that the grain number and grain weight per plant might be considered for breeding of buckwheat. Meanwhile， 51 varieties were classified into 8 major groups by cluster analysis， of which PI 658426 and PI 427236 in group Ⅶ were regarded as the high-yield varieties， 6 varieties in group Ⅷ showed excellent traits. Finally， according to the comprehensive D value， 11 sweet buckwheat varieties were identified as high-yield and high-quality.
Roegneria komarovii is a plant of Roegneria spp in Triticeae with the characteristics of drought and disease resistance， and it also is an excellent perennial forage. In order to analyze the mechanism of salt tolerance and the expression of disease resistance genes by real-time quantitative PCR （qRT-PCR）， the reference genes that expressed stably under different abiotic stress were screened. The expression of 8 wheat internal reference genes were assessed including Actin protein （Actin1， Actin2， Actin3）， beta-tubulin （BTUB）， Cyclophilin， glyceraldehyde-3-phosphate （GAPDH）， histone 3 （H3） and elongation factor-1-alpha-subunit （EF1a1） in Roegneria komarovii samples under the stresses of salt， drought and high temperature， and using geNorm and BestKeeper softwares to evaluate the stability of them. SnRK2 gene was used to verify the stability and reliability of the selected internal reference genes. Based on the statistical analysis of qRT-PCR results，the expression abundance and stability of 8 candidate reference genes were different under different stress treatments. The stability of Cyclophilin and GAPDH were the best under salt and drought treatments. EF1a1 and Cyclophilin had the best stability under high temperature treatment. The results showed that Cyclophilin， GAPDH and EF1a1 were highly expressed and stable in the various organs. Cyclophilin was selected as the most suitable reference gene through the stability evaluation of abiotic stress. The results provided foundation for investigating the molecular mechanism of salt stress tolerance in Roegneria komarovii.
In order to screen out table grape varieties with strong drought resistance， the relationship between leaf anatomical structure and drought resistance of table grape varieties was studied. 10 cuttings of one-year-old table grape varieties were used as test materials for potted drought stress. Its growth vigor， leaf relative water content and leaf anatomical structure were measured， and drought resistance of table grape varieties was comprehensively evaluated by principal component analysis. The results showed that with the deepening of drought stress， the drought symptoms increased but relative water content decreased significantly in leaves of 10 grape varieties. According to the drought coefficient， the sensitivity of each drought resistance related index to drought stress was sorted， and the order was palisade tissue and spongy tissue ratio > cell tightness ratio > thickness of palisade tissue > thickness of lower epidermis > leaf thickness > stem diameter = shoot length > thickness of upper epidermis = stem length = spongy ratio > thickness of spongy tissue > leaf width > leaf length. Further through principal component analysis， the drought resistance ability of 10 table grape varieties were‘Blackcrunchy Seedless’>‘Sunshine Muscat’ >‘Crimson Rose’ >‘Flame Seedless’ >‘Hutai 8’ > ‘Summer Black’ > ‘Wagamichi’> ‘Zitian Seedless’> ‘Silk Road Red Rose’ > ‘Sweet Sapphire’. The results would provided scientific reference for the introduction and further promotion of table grape varieties in arid and semi-arid regions of China.
In order to provide theoretical reference for the breeding， this paper used the fruit and seed kernel of sour jujube from 10 different origins， the nutritional components and the bioactive ingredients of fruit， the bioactive ingredients of seed kernel （jujuboside A， B） were determined. The membership function method was used for comprehensive evaluation. The results showed that the average contents of soluble sugar， titratable acid， soluble protein and amino acid in jujube fruits from different producing areas were （2.69±0.83） mg·g-1，5.35%±2.40%、（32.05±17.45） mg·g-1 and（9.39±3.65） mg·g-1， respectively. The average contents of vitamin C， polysaccharide， total flavonoids and total phenol in bioactive components were （43.88±18.26） mg·100 g-1、（51.12±16.48）mg·g-1、（47.57±15.73） mg·g-1 and（25.34±17.58） mg·g-1，respectively. The highest content of jujuboside A was in Shanxi Lvliang， with the content of 0.429 mg·g-1， and the lowest was in Shanxi Changzhi， with the content of 0.138 mg·g-1. The highest content of jujuboside B was in Beijing Pinggu， with the content of 0.186 mg·g-1， the lowest content was in Shanxi Changzhi， with the content of 0.060 mg·g-1. The comprehensive evaluation of membership function showed that， the order of fruit quality evaluation of sour jujubefrom high to low was S6 （Ningxia Zhongwei ），S8 （Shaanxi Yulin） ，S1（Shanxi Lvliang）， S5（Xinjiang Kashgar），S4 （Liaoning Chaoyang） ，S2 （Shanxi Changzhi），S3（Hebei Tangshan），S10 （Beijing Pinggu）， S7 （Hebei Xingtai） ，S9 （Hebei Chengde） . The order of quality evaluation of seed kernel of sour jujube from high to low was S10 （Beijing Pinggu） ，S1（Shanxi Lvliang），S4 （Liaoning Chaoyang） ，S9 （Hebei Chengde） ，S7 （Hebei Xingtai）， S3（Hebei Tangshan ）， S8 （ Shaanxi Yulin） ，S5（Xinjiang Kashgar），S6 （Ningxia Zhongwei），S2 （Shanxi Changzhi）. Above results provided reference for development and utilization of excellent sout jujube varieties.
In order to reveal the physiological mechanism of Cynodon dactylon drought resistance， screen the key indicators affected drought resistance under different drought stresses， and explore the different response of different drought-resistant Cynodon dactylon to drought stress， 2 types of different drought-resistant Cynodon dactylon were used as experimental materials. The changing laws of leaf relative water content， relative electrical conductivity， photosynthetic pigment content， antioxidant enzyme activity and osmotic adjustment substance content under gradual slow drought stress were analyzed. The results showed that， with the decrease of soil water content and the intensification of drought stress， the relative water content of the tested Cynodon dactylon leaves continued to decrease， while the relative electrical conductivity and the contents of malondialdehyde， soluble proteinand proline showed an increasing trend. The pigment content and the activities of 3 antioxidant enzymes showed a trend of first increasing and then decreasing. Compared with drought-sensitive materials， the drought-resistant Cynodon dactylon maintained higher activities of antioxidant enzymes under moderate to severe drought stress， and accumulated more proline and soluble protein contents， which lead to a slow increase of electrical conductivity and malondialdehyde. It showed that the different germplasm with same drought-resistant had different response mechanism to drought. C118 showed high chlorophyll content， while C138 showed high carotenoid content. Grey correlation analysis indicated that， under moderate drought （14 d）?， relative conductivity， carotenoids content and superoxide dismutase activity had greater impact on the drought resistance of Cynodon dactylon； while under severe drought （20 d）， the contents of proline and soluble protein showed high correlation with resistant to drought. The above results clarified the physiological response mechanism of different drought-resistant Cynodon dactylon to drought， which laid the foundation for the selection of drought-tolerant grass species and water-saving technology.
Biofilm is a special extracellular structure of bacteria to adapt environmental stress. The physiological and metabolic activities of bacteria will change during the transition from the planktonic state to a biofilm. To investigate the changes of physiological metabolic pathways and the molecular regulation mechanism of biofilm formation， RNA-Seq technology was used in this study to examine the global gene expression profiles of Escherichia coli O157∶H7 during biofilm and planktonic growth states. The results showed that， in comparison to the planktonic growth state， there were 1 652 differentially expressed genes in biofilm growth state of E. coli O157∶H7， including 821 up-regulated genes and 831 downregulated genes. Genes involved in flagella assembly， bacterial chemotaxis in connection with bacterial motility， and bacterial two-component system regulatory system relating to environmental factors were up-regulated during E. coli O157∶H7 biofilm formation， while the genes involved in ABC transporters of nutrients and signal molecules were downregulated. In addition，changes in carbon metabolism， nitrogen metabolism， fatty acid metabolism and other metabolic pathways were found during E. coli O157∶H7 biofilm formation. Above results provided a scientific basis for the further study of biofilm formation mechanisms.
Diseases are the main factors threatening crop yield， and their characteristics are complex and varied. It is often difficult to accurately identify them for agricultural practitioners lack professional knowledge. In the past， image recognition methods aimed at a single crop， and extracted disease features for recognition after image segmentation， which could not adapt to multiple crops. Aiming at this problem， rice， tomato， citrus and apple were as the research objects， a deep learning network framework was built based on ResNet model， and a new full connection layer containing Squeeze-and-Extension （SE） module was designed. The weight of pre-training on ImageNet was imported， and the disease model was trained on the disease data set. In order to expand the image data， the original image of the training set was increased or decreased in brightness， randomly rotated and mirror flipped. Based on the expanded training set， the disease identification and disease degree grading were studied. The results showed that the average disease degree accuracy rate of identifying rice， citrus， tomato and apple was 94.16%， and the average disease type accuracy rate was 92.45%. The disease monitoring platform was developed based on the trained model and c#.net core to realize the intelligent identification of crop diseases.
Crop variety plays a key role in improving agricultural production and income. Aiming at the safety problems of seed industry， in order to realize the rapid recognition and protection of corn varieties， a variety recognition model based on ear image was proposed. After image preprocessing， 1 000 images of corn ears were divided into training set， validation set and test set according to the ratio of 7∶2∶1. And the data sets were enhanced by translation， flipping and other data processing. Using transfer learning technology， the pre-trained weights and parameters were transferred to NASNet-mobile， Xception， ResNet50V2， MobileNetV2， DenseNet121 and VGG16 for comparative experiments. The results showed that the performance of NASNet-mobile was best， and the recognition rate reached 90%. At the same time， different optimization algorithms were used for comparative experiments， and the result showed that Adam model performed better. Based above results， experiments were carried out under a variety of different full connection layer modules. The results showed that， when the number of full connected layers was 2 and the dimension was 256， better corn ear image features could be obtained， and the recognition accuracy of the final model under the full connection layer module reached 95%， which increased by 5% compared with NASNet-mobile. It realized the variety classification and recognition of corn ear image， which provided intelligent technical support for the rapid and accurate identification of corn varieties and the protection of germplasm resources.
In order to research the influence of research materials plate of centrifugal feeder on broken rate， through the motion analysis of feed particles in extractor plate， this paper determined the factors affected the broken rate. Feed particles cohere model was established using EDEM software， and the single factor experiment was conducted to get the influence of various factors on the breakage rate. According to the results of single factor three factors， three levels orthogonal experiment was designed， the secondary and parses the multivariate regression model was constructed and explained between floor breakage and feed throw materials plate number centrifugal plate angle floor， and then the structure parameters of centrifugal plate was optimized. The results showed that the impact rank on the breaking rate of feed was： curvature radius > floor number > floor tilt plate. The interaction between the number of floor and the radius of floor curvature had a significant effect on the coefficient of variation of distribution. The regression analysis and optimization showed that when the number of floor was 6， the inclination angle was 12.8°， the radius of floor curvature was 71.5 mm， the minimum value of breakage rate reached to 2.13%. The results of the verification test showed that the measured values were basically consistent with the theoretical values of the model. The research results provided a reference for the parameter optimization of the feeding plate of centrifugal feeding machine.
Schistosomiasis is a catastrophic zoonotic disease and parasitic illness caused by Schistosoma （an aquatic parasite） for most mammals. Domestic animals， including cattle， sheep， goat， pig and so on， are susceptible to Schistosoma. This paper systemically reviewed the life cycle， transmission chain， and clinical symptoms of schistosomiasisin livestock， and analyzed the epidemiological characteristics， diagnostic techniques， and comprehensive control measures of schistosomiasis， which was expected to provide the guidance for the control and thearpy of Schistosomiasis in livestock.
Powdery mildew and anthracnose are important diseases which affect the production of natural rubber. In order to identify the inhibitory effect of lipopeptides from Bacillus subtilis Czk1 on anthracnose and powdery mildew of rubber tree，rubber seedling Reyan 7-33-97 was used as material， the effects of the lipopeptide extraction of strain Czk1 on the mycelia growth morphology and conidial development of Colletotrichum gloeosporioides were studied by co-culture method. Vitro and pot experiments were carried out to evaluate the inhibitory effect on rubber tree anthracnose and powdery mildew. The results showed that Bacillus subtilis Czk1 lipopeptide could induce mycelial deformation and breakage of C. gloeosporioides. The minimum Czk1 lipopeptide concentration of inhibiting C. gloeosporioides was 40 mg·L-1， and the EC50 value of inhibiting condia germination of C. gloeosporioides was 3.80 mg·L-1. When the Czk1 lipopeptide concentration was 40 mg·L-1， the inhibition rate of condia germination of C. gloeosporioides was 68.84%. When the concentration of lipopeptide was 1 000 mg·L-1， the incidence rate ofrubber tree anthracnose decreased 43.40% and 49.90%， the disease index of rubber tree powdery mildew decreased 32.60 and 21.60， and the inhibition effect of powdery mildew of rubber tree was 45.60%. The results showed that the lipopeptide of strain Czk1 could effectively reduce the incidence of anthracnose and powdery mildew， inhibit the growth of the pathogen and delay the expansion of the disease， which had good biocontrol potential to control the leaf diseases of rubber trees.
To investigate the causes of ulcers on the surface and a large number of deaths of the Cynoglossus semilaevis in a certain farm， bacterial isolation was performed from the liver， spleen and kidney of the diseased fish， and dominant strains 8-0634 and 8-0635 were obtained from the spleen and kidney， respectively. The strains were used for artificial infection experiments， and the results showed that only strain 8-0635 could cause the death of the Cynoglossus semilaevis and the symptoms were scale off， ascites， intestinal congestion to the outward， spleen， kidney and other organs atrophy congestion. A large amount of inflammatory cell infiltration occured between tissues. According to the results of Gram staining and physiological and biochemical experiments， the strain was initially identified as Vibrio harveyi， and then the phylogenetic tree was constructed based on the housekeeping gene and16S rRNA sequence to further identify the pathogenic bacteria as Vibrio harveyi. The pathological description and drug susceptibility test were performed. The results of drug susceptibility test showed that the pathogen was high sensitivity to various drugs such as cefoperazone， florfenicol， chloramphenicol and ampicillin. This study provided a theoretical basis for disease prevention and control of fish infected with Vibrio harveyi.
In order to study the effects of natural low temperature on the physicochemical indexes of starch of different rice varieties and cooking and eating quality of rice at filling stage， 7 high-yield and high-quality rice varieties were selected and processed into milled rice and rice flour， respectively. The physicochemical indexes of starch， viscosity， hardness and eating value of rice were measured at room temperature and low temperature. The results showed that low temperature during grain filling stage of rice increased significantly amylose content， setback， peak time， gelatinization temperature and rice hardness， the maximum amylose content was 47.4%. While it decreased obviously gel consistency， peak viscosity， breakdown and rice viscosity， the viscosity of rice was all reduced to 30~50 mm， and ultimately led to poor cooking and eating quality. The low temperature tolerance of 7 rice varieties was evaluated by taste value and starch physical and chemical indexes， the results showed ‘Y liangyou 911’ had the highest low temperature tolerance of rice quality， and ‘Y liangyou 1928’ had the lowest of rice quality. The results of this study showed that appropriate cultivation measures should be taken to cope with the influence of low temperature on rice quality during the grain filling period， which provided a new idea for screening and cultivating low-temperature tolerant and high-quality rice.
In order to determine the best process parameters for hot-air drying of Lentinus edodes， a multi-objective optimization was studied with fresh Lentinus edodes as the test object. Taking relative humidity， wind speed and unit load as independent variables， and the color difference， water-soluble protein content and drying time of dried mushrooms as response values， a multi-objective comprehensive scoring optimization model for hot air drying of mushrooms was established， and the best process parameters for hot air drying of mushrooms was obtain by response surface method. The results showed that when color difference was 3.58， water-soluble protein content was 46.39 mg·g-1， drying time was 12.5 h， corresponding to the drying condition was 50 ℃， the best drying process parameters were relative humidity 27.1%， wind speed 5 m·s-1， and the unit load 4 kg·m-2； comparing the model prediction value of the optimization target with the experimental value， the average relative error was only 6.6%， and the maximum relative error was 7.4%. The results showed that the comprehensive scoring prediction model based on response surface method could not only be used in the hot-air drying process of Lentinus edodes， but also could provide theoretical guidance for improving the nutritional and sensory quality of dried Lentinus edodes.
With the rapid development of industrialization and urbanization， sludge， as a by-product of sewage treatment， is increasing in yield. Organic pollutants and heavy metals in sludge taking some difficulties to make sludge harmless and resourceful. The biochar produced from sludge pyrolysis is a new way of sludge treatment in recent years， which has the advantages of stability， reduction and recycling. Sludge biochar is a kind of soil improvement material with good performance， which can improve the physical and chemical properties of soil， such as bulk density， pH， cation exchange capacity， heavy metal content， etc. In addition， Sludge biochar can also improve soil fertility and promote plant growth. This study summarized the composition of the sludge source and biochar sludge pyrolysis mode of production and characterization， and discussed the sludge biochar application of heavy metals on soil physical and chemical properties and the influence of mechanism. The research and application progress of single and cothermal sludge biochar were analyzed， and the main problems and future development direction of sludge biochar for soil improvement were put forward.
In order to explore the effects of different soil amendments on the improvement of low-lying saline alkali land in Northern Shaanxi， the effects of three soil amendments （desulfurization gypsum， “Jinfufeng” and humic acid） on soil physical and chemical properties， rice yield and economic benefits were studied and compared by means of field experiment and indoor analysis. The results showed that the 3 soil amendents could effectively reduce soil bulk density， improve soil physical properties and reduce soil pH. Humic acid could also significantly reduce the salt content of surface soil. In addition， “Jinfufeng” soil amendents and humic acid had significant effects on the content of soil organic matter and total nitrogen， but had no significant effects on the available potassium and available phosphorus. Desulfurized gypsum had a significant effect on the content of soil available potassium， but had no significant effects on the organic matter， total nitrogen and available phosphorus. The application of soil conditioner could significantly improve the 1 000 grain weight and yield of rice， which increased by 10.19%～13.59% and 13.54%～27.95%， respectively， compared with the control. The 1 000 grain weight and yield of humic acid amendments treatment were the highest， reaching 23.4 g and 7 380 kg·hm-2， respectively. Through the analysis of economic benefits， it was found that the application of modifier could significantly improve the output value and net profit of rice. Among them， the application of humic acid modifier could obtain the maximum output value， net profit and yield investment ratio. Considering the rice quality， rice yield and economic benefits， it was suggested to give priority to humic acid soil to improve the low-lying saline alkali land in Northern Shaanxi.
To clarify the effects of nitrification inhibitor on nitrogen high-utilization in the summer maize production， two-year field experiments were conducted to determine the effects of nitrification inhibitor （2-chloro-6-trichloromethylpyridine， CP） application on grain yield and nitrogen accumulation and transportation and utilization of summer maize under reduced nitrogen （N） treatments in Henan province. The results showed that， compared with the normal N fertilization treatment， N reduced by 20% with CP had no effect on the each organ of plant and total dry matter accumulation， as well as N absorption and accumulation. There was no difference in grain yield between treatments and normal application. With N application increased， the amount of N transportation in the plant showed first increased and then decreased. The treatment of N reduced by 20% with CP had the highest N transportation amount and transportation rate with 62.41 kg·hm-2 and 44.54%， respectively， and the contribution rate to grain was 33.96%. The nitrogen partial factor productivity （NPFP） decreased with N application increased with the average 58.94 kg·kg-1. Amount of pure N absorbed per 100 kg grain was averagely 1.96 kg and highest value was obtained in treatment of N reduced by 10%. Based on the grain yield， N transportation and accumulation and utilization， the application of N reduced by 20% with CP could maintain the high and stable yield， promote N use efficiency， and reduce cost and increase efficiency in maize production.
To explore the effects of salt stress and phosphorus supply level on photosynthetic characteristics and total biomass of different switchgrass（Panicum virgatum L.）varieties at seedling stage， octoploid Alamo， Alamo and Pathfinder were used as hydroponic materials， and 2 salt stress levels （A1 non-salt stress， A2 salt stress） and 4 phosphorus supply levels （B1 no phosphorus， B2 low phosphorus， B3 high phosphorus， B4 total phosphorus） were set. The effects of salt stress and phosphorus supply levels on different photosynthetic indexes and total biomass of 3 switchgrass varieties at seedling stage were analyzed， and the photosynthetic characteristics and characteristics of 3 switchgrass varieties were further revealed. Under the same salt treatment， the net photosynthetic rate， stomatal conductance， transpiration rate， chlorophyll content and total biomass of 3 switchgrass varieties at seedling stage all increased with the increase of phosphorus level. Compared with non-phosphorus treatment， the net photosynthetic rate， stomatal conductance， transpiration rate， chlorophyll content， total biomass of octoploid Alamo in total phosphorus treatment under non-salt stress and salt stress increased by 21.84%， 42.86%， 21.98%， 17.45%， 246.52% and 14.63%， 16.67%， 71.10%， 115.45%， 91.00%， respectively； Alamo increased by 15.89%， 28.57%， 37.62%， 95.16%， 115.32% and 15.28%， 100.00%， 37.20%， 188.33%， 113.97%， respectively； Pathfinder increased by 18.33%， 75.00%， 42.60%， 86.87%， 145.85% and 23.35%， 100.00%， 50.35%， 108.20%， 405.88%， respectively. Under the same salt treatment， the intercellular CO2 concentrations of 3 switchgrass varieties at seedling stage decreased with the increase of phosphorus level， which decreased by 49.68%， 40.41%， 40.21% and 50.12%， 68.07%， 63.11% in total phosphorus treatment under salt stress and non-salt stress compared with no phosphorus treatment. The correlation analysis indicated that the total biomass was positively correlated with transpiration rate， stomatal conductance and net photosynthetic rate in octoploid Alamo， and the total biomass was closely positively correlated with chlorophyll content in Alamo， while the total biomass was also negatively correlated with intercellular CO2 concentration in octoploid Alamo and Alamo. Comprehensive analysis showed that octoploid Alamo had the better adaptability and more suitable for planting under salt stress and low phosphorus stress.
To explore the effect of different soil water content on citrus fruit quality， the 10-year-old ‘Yichang mandarin orange’ was as the object in 2018—2020， and 3 treatments （T1： 23%~26%； T2： 20%~23%； T3： 17%~20%） of soil water content were set in the young fruit period， fruit expansion period， and color change and sugar-increasing period. The quality of citrus was analyzed by measuring total fruit weight， total pulp weight， juice weight， edible rate， juice yield， fruit shape index， soluble solids， total sugar， titratable acid and Vc content. The results showed that the soil water content in the young fruit period was extremely significantly positive correlated with the fruit shape index， the soil water content in the fruit expansion period was significantly negatively correlated with the total sugar content， and the soil water content in the color change and sugar-increasing period was significantly positive correlated with the fruit shape index， and was significantly negatively correlated with the total sugar content. With the decreasing of soil moisture content， the weights of whole fruit， fruit weight and juice all showed downward trend， the total sugar content showed upward trend， and the content of soluble solids increased firstly and then decreased. The higher the soil moisture content in the young fruit stage and the color-changing sugar-increasing period， the higher the fruit type index； the lower the soil moisture content in the fruit swelling period and the color-changing sugar-increasing period， the higher the fruit sugar content. When the soil water content was 23%~26%， the shape quality was best and flavor quality was medium. When the soil water content was 20%~23%， the flavor quality was best and the shape quality was medium. When the soil water content was 17%~20%， the flavor and shape quality were worst. So it was recommended that the soil water content should be adjusted to 20%~23% during actual citrus planting.
To improve the resource utilization of straws， an experiment was conducted with rice straw， corn stalk and Artemisia argyi straw， in which the growth and quality of pleurotus ostreatus was investigated. In this research， 7 different substrate combinations were compared， including 100% rice straw （CK1）， 100% corn stalk （CK2）， 100% Artemisia argyi straw （CK3），60% rice straw +20% corn stalk +20% Artemisia argyi straw （T1）、20% rice straw +60% corn stalk +20% Artemisia argyi straw （T2）， 20% rice straw +20% corn stalk +60% Artemisia argyi straw （T3） and 33% rice straw +33% corn stalk +33% Artemisia argyi straw （T4）. The results showed that the growth of mycelium was limited under 100% rice straw（CK1） or 100% corn stalk （CK2）treatment and it required more time for budding， which resulted in the lowest yields and bioconversion efficiencies under both of these two treatments. In contrast， the mixed treatments （T1~T4） improved the average growth rate of mycelium and the bioconversion efficiency， and the yield was increased by 112%~188% and 38.9%~88.9% compared respectively to CK1 and CK2. Comparing with the 100% Artemisia argyi straw treatment （CK3）， the 20% or 33% Artemisia argyi straw treatment showed a certain increase in isoleucine， leucine， lysine and total phenol content and an increase by 32.2%~52.9% in soluble protein content. Compared with CK1， CK2 and CK3 treatments， the polyphenol oxidase activity increased to a certain extent， and the reducing sugar content increased by 10.0%~103.3%， 26.9%~134.6% and 32.0%~144.0% under the mixed treatments （T1~T4）， respectively. This study suggested that the mixed substrates of these three straws were suitable for the cultivation of pleurotus ostreatus. In addition， the appropriate addition of Artemisia argyi straw was beneficial to improve pleurotus ostreatus quality. The results could provide theoretical support for the comprehensive utilization of straw resources.
To research the effects of molybdenum and zinc nutrition on the physiological characteristics and quality of flue-cured tobacco， flue-cured tobacco line LY1306 was used as material. Field experiments were conducted to compare the effects of molybdenum and zinc nutrition on the activities of key enzymes in carbon and nitrogen metabolism， plastid pigment content， photosynthetic performance， chemical components and economic properties of flue-cured tobacco leaves by spraying clear water （CK）， 0.1% ammonium molybdate solution （T1）， 0.2% zinc sulfate solution （T2）， 0.1% ammonium molybdate solution + 0.2 % zinc sulfate solution （T3）. The results showed that compared with CK， T1， T2 and T3 treatments enhanced the activities of nitrate reductase （NR）， glutamine synthetase （GS） and sucrose invertase （INV） in different degrees during the development of flue-cured tobacco leaves， increased the net photosynthetic rate （Pn） and plastid pigment content of flue-cured tobacco， promoted the accumulation of dry matter in tobacco leaves， and significantly increased the yield， output value， average price and the proportion of superior tobacco leaves. At the same time， each treatment also significantly increased the total sugar， reducing sugar and potassium content of flue-cured tobacco leaves， increased the sugar alkali ratio and potassium chloride ratio of tobacco leaves， and improved the coordination of chemical components of tobacco leaves. T3 treatment was the best in all indexes. In conclusion， the combined application of molybdenum and zinc had the best effect in improving the carbon and nitrogen metabolism intensity and photosynthetic performance of flue-cured tobacco， coordinating the chemical composition of tobacco leaves and improving the quality of flue-cured tobacco leaves. The results provided theoretical basis for the rational application of molybdenum and zinc nutrition in flue-cured tobacco production.
To study the soil volume fractal dimension of 3 types at Shixiakou reservoir， Qingshuihe county， Inner Mongolia， the soils of Pinus tabuliformis， Larix gmelinii and Caragana korshinskii ×Hippophae rhamnoides were as materials， and the grassland was as control. The ring knife was used for multi-point sampling， and the soil physical and chemical properties and soil volume fractal dimension were measured. The single ring soil column method was used to observe the soil water infiltration， and the linear regression analysis was carried out between the soil volume fractal dimension and the infiltration characteristics. The results showed that different plantations in the study area could significantly improve soil nutrients， retain soil fine particles， reduce soil volume fractal dimension and improve water infiltration capacity. The soil volume fractal dimension showed grassland （2.30）， Caragana korshinskii × Hippophae rhamnoides （2.28） > Larix gmelinii （2.24）> Pinus tabulaeformis （2.18）. The initial infiltration rate， steady infiltration rate and 1 h cumulative infiltration were as follows： Pinus tabulaeformis （11.0 mm·min-1， 1.2 mm·min-1，116 mm） > Larix gmelinii （8.5 mm·min-1， 0.9 mm·min-1， 80 mm） > Caragana korshinskii × Hippophae rhamnoides mixed forest （6.2 mm·min-1， 0.8 mm·min-1， 62 mm） > grassland （4.7 mm·min-1， 0.45 mm·min-1， 51 mm）. Vegetation retained protect soil fine particles by weakening natural erosion such as surface runoff and wind erosion， so as to improve the uniformity of pore structure and texture， and then improve the infiltration capacity. In the study area， soil fractal dimension could characterize soil infiltration capacity， and Pinus tabulaeformis forest had strong water conservation capacity at Shixiakou reservoir.
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