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- Abstract：In order to explore the effect of ear-to-plant height ratio on maize yield and yield composition, taking 125 maize materials as study object, field experiments were conducted to investigate effects of plant height, ear height, ear-to-plant height ratio on the kernel number, thousand kernel weight, and yield of maize. At the same time, the meta-analysis was adopted to analyze the data in related literature published from 1985 to 2019. The results showed that: 1)Plant height and ear height had significant effects on kernel number, thousand kernel weight and yield(P<0. 01). The ear-to-plant height ratio had significant effect on kernel number and thousand kernel weight(P<0. 05). 2)In this study, plant height ranged from 175. 10 to 295. 00 cm, ear height ranged from 53. 50 to 127. 67 cm, and ear-to-plant height ratio ranged from 0. 29 to 0. 49. With the increase of plant height, ear height and ear-to-plant height ratio, the kernel number first increased and then decreased. When plant height was 267. 76 cm, ear height was 99. 46 cm and ear-to-plant height ratio was 0. 40 cm, the kernel number reached the maximum. The thousand kernel weight first increased linearly with the increase of plant height, ear height and ear-to-plant height ratio, and then remained at a stable level. When the thousand kernel weight reached the maximum, the plant height was 292. 25 cm, the ear height was 80. 95 cm, and the ear-to-plant height ratio was 0. 50. The yield increased with the increase of plant height and ear height. With the increase of ear-to-plant height ratio, the yield first increased and then decreased. When the ear-to-plant height ratio was 0. 42, the yield reached the maximum. 3)The regression tree analysis of literature and field experiment data showed that plant height had a greater influence on kernel number than ear-to-plant height ratio. In view of the important influence of ear-to-plant height ratio on lodging resistance and kernel number of maize, the ear-to-plant height ratio is the key index of maize yield improvement. In conclusion, the stronger lodging resistance and higher kernel number are conducive to the further improvement of maize yield at ear-to-plant height ratio within 0. 40 to 0. 42.Keywords：maize;plant height;ear height;kernel number;ear-to-plant height ratio;yield12|12|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To select silage maize varieties suitable for cultivation in the Huang-Huai-Hai area, the agronomic traits, biological yield, nutritive value and fermentation quality of whole-plant maize silage of 16 maize varieties were measured and comprehensive evaluation was conducted by using grey relational analysis. The results showed that: There were significant differences in the plant height, leaf numbers, number of green leaves, number of yellow leaves, ear height, stem diameter and proportion of plant parts(P<0. 05). The whole-plant yield was significantly and positively correlated with the ratio of leaf and ratio of stem(P<0. 05). There was a significantly positive correlation between starch content and ratio of grain(P<0. 05), but significantly negative correlations between neutral detergent fiber, acid detergent fiber and ratio of grain(P<0. 01). Compared with the grain and forage maize varieties, the silage maize varieties including ‘Dajingjiu 26', ‘Jingjiu silage 16', ‘Jingke silage 932'and‘Yayu No. 8'had the yield advantages because of their taller plant height and higher proportions of leaf and stem. However, the grain and forage maize varieties, such as ‘Denghai 605', contained higher nutritive value including higher starch content and lower fiber content due to higher proportion of grain. All varieties performed excellent silage quality and the differences were mainly shown in the contents of starch, acetic acid and ammonia nitrogen/total nitrogen. Considering the dry matter yield, grain yield, nutrient content and fermentation quality, ‘Denghai 605', ‘Dedan No. 5', ‘Zhengdan 958', ‘Xianyu 045', ‘YF 3240'and ‘Nongda 372'displayed high correlation degree and were suitable to be popularized as whole plant silage corn varieties in the Huang-Huai-Hai region.Keywords：silage maize;yield;agronomic traits;nutritive value;silage quality3|13|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To optimize the nitrogen fertilizer application method for winter wheat micro-sprinkler irrigation integration, ‘Jimai 22'was used as study material under micro-sprinkler irrigation and fertilizer integration conditions from 2018 to 2019. Three nitrogen application rates, 120(N1), 210(N2)and 300 kg/hm2(N3), were set. Under each nitrogen application rate, two nitrogen application methods were set, which were one-time nitrogen application at jointing stage(JS)and equal amount and split nitrogen application at jointing stage, booting stage, anthesis stage and filling stage(4T). The yield, protein composition content, dough quality, nitrogen accumulation and utilization, and nitrate nitrogen content in soil of winter wheat were determined. The results showed that: Under micro-sprinkler irrigation, split nitrogen application(4T)significantly promoted post-anthesis dry matter accumulation, significantly increased the 1 000-grain weight of winter wheat, and then significantly increased grain yield. N3-4T treatment had the highest yield of 9 951. 2 kg/hm2. Under the same nitrogen topdressing method, JS treatment significantly increased contents of globulin, gliadin and gluten, and significantly prolonged dough stability time with the increase of nitrogen application rate. With the increase of nitrogen application rate. Although the total protein content of grain in 4T treatment did not change, the contents of albumin, gliadin and gluten decreased, the wet gluten content and dough formation time in N3 treatment decreased significantly. Under the same nitrogen application rate, compared with JS treatment, 4T treatment significantly increased dry matter accumulation and harvest index post-anthesis, 1 000-grain weight and grain yield. However, 4T treatment significantly reduced both gliadin and gluten ratio, and the dough formation time and stabilization time were significantly lower than those of JS treatment. 4T treatment significantly increased nitrogen partial productivity, significantly reduced nitrate nitrogen content in deep soil, and reduced the risk of leaching and migration of nitrate nitrogen to deep soil. In general, increased nitrogen application rate significantly increased grain yield and protein content, and split nitrogen application further improved grain yield and protein content, effectively improved nitrogen partial productivity, and reduced the risk of soil nitrate leaching into deep soil.Keywords：micro-sprinkler irrigation;nitrogen fertilizer management;winter wheat;yield;dough stability time;nitrogen utilization7|12|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to investigate the impact of oat and potato strip intercropping on crop yields and land utilization rate in the semi-arid northern China, a 3-year field experiment(2019-2021)was carried out in Youyu County, Shanxi Province. The experiment contained 3 cropping systems, which were sole oat cropping, sole potato cropping and oat and potato strip intercropping. The yield effect, land equivalent ratio(LER), and border row effect of intercropping system were studied. The results showed that: Oat and potato strip intercropping had significant yield advantage and the LERs were 1. 11, 1. 07, and 1. 17 in the three years, respectively. The grain yield of oat in intercropping border 1 row was significantly higher than that in other intercropping rows and sole row, which contributed approximate 35. 6% to 38. 1% of the total grain yield of intercropping system in 2019-2021. Furthermore, yield composition analysis showed that the increased aboveground biomass, ear number and kernel number per ear were the determinants for the increased grain yield of one row oat planting in intercropping border. On the contrary, the lower tuber yield per plant and marketable yield per plant of potato in one row potato planting in intercropping border resulted in about 1. 0% to 26. 2% decrease in potato yield of intercropping. In conclusion, the oat and potato strip intercropping increased LER and had yield advantages, and the border row effect of oat was responsible for the strip intercropping yield advantage.Keywords：oat and potato intercropping;yield;land equivalent ratio;border row effect17|15|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to find out a set of efficient water conservation measures suitable for orchards in the Loess Plateau, and to improve the water use efficiency of fruit trees, ‘Malus prunifolia (Willd. )Borkh. 'and ‘M26' rootstocks were used as experimental materials under pot conditions. The physiological responses of two kinds of apple rootstocks to different water retention treatments were studied by setting four treatments: control(CK), water retaining agent treatment(A), buried brick treatment(B)and buried brick+water retaining agent treatment(AB). The results showed that: 1)Both burying bricks and water-retaining agent alleviated the decreasing trend of soil water content; from the 21 st day of water control, the net photosynthetic rate and SPAD value of all treatments began to decrease due to drought stress. However, compared with the control, the three water conservation treatments could slow down the effect of drought stress on plant growth, maintain plant photosynthetic rate and stabilize leaf SPAD value. 2)The treatment of buried brick superimposed water-retaining agent significantly alleviated the effects of water shortage on plant root length, root surface area and root growth. Water retention treatment increased the root-shoot ratio and maintained the number of stomata in leaves. 3)The physiological response of ‘M26' with weak stress resistance was more sensitive under different water retention treatments, and the growth promoting effect of each treatment on ‘M26' was AB>B>A, while for ‘Malus prunifolia (Willd. )Borkh. ' with stronger stress resistance, any kind of water conservation measures could reduce the effect of water shortage on plants. In summary, three different water conservation treatments reduced the effect of water shortage on plant root morphology and photosynthesis. Water retention treatment alleviates drought stress by keeping stomata open, maintaining normal photosynthesis, promoting root development and increasing root water absorption area. For Arbor rootstocks, it is suggested that single water conservation measures or superimposed treatment water conservation measures could be selected in the production of Arbor rootstocks, while for dwarfing rootstocks, superimposed water conservation measures could be chosen.2|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the distribution of microorganisms in different niches of Chinese chives(Allium tuberosum Rottl. ex Spreng. ), this study used high-throughput Illumina sequencing technology and various software to analyze the obtained data, determine the core species of different niches and predict the function of microorganisms in different locations by PICRUSt2. The results showed that the richness and diversity of microbial communities in the root and rhizosphere soil of Chinese chives. At underground part of Chinese chives were higher than those in other locations, and the main core species were Proteobacteria and Actinobacteria. The relative abundance of Firmicutes and Bacteroidetes in the aboveground compartments such as Chinese chives leaves was higher. The main function of endophytic bacteria in the aboveground part of Chinese chives is to carry out a series of metabolic activities through various organic systems, while the microorganisms in the underground part are mainly involved in the processing of genetic information and the basic activities of cells. Proteobacteria is mostly related to the basic life activities of cells, while Firmicutes and Bacteroidetes that play a role in the aboveground part may be involved in a series of metabolic activities of Chinese chives. This study provided some theoretical references for the future research and development of disease and insect resistance and cold resistance of Chinese chives.Keywords：niche;endophyte;phylloplane;rhizosphere;Chinese chives;co-occurrence networks10|26|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To exploit the anti-fatigue function of bovine bone collagen peptide(BBP), the amino acid composition and peptide sequence of BBP were characterized. Sixteen 7-week-old SPF Balb/c mice were divided into two groups randomly including the control group(normal saline)and the peptide intervention group(w(BBP)=200 mg/kg)), and all were given daily oral gavage. After 4 weeks of BBP intervention, the weight-bearing swimming time and post-exercise metabolic accumulation content of mice were determined. After 18 weeks of BBP intervention, the content of serum oxidant and inflammatory factors, and intestinal flora composition were determined. The results showed that: 1)The proportion of hydrophobic amino acids was 61. 37%. Most of the peptides belonged to the protein P02453(α1 chain of type I collagen). 2)After BBP intervention, the weight-bearing swimming time of mice was significantly increased, and the serum ammonia concentration was significantly decreased, the glutathione concentration was significantly increased(P<0. 05), indicating the potential anti-fatigue effect of BBP. 3)After BBP intervention, the serum superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)of mice in a non-exercise state were significantly increased, and malondialdehyde(MDA)was significantly decreased(P<0. 05), indicating the potential antioxidant capacity of BBP; In terms of immunity, the concentration of anti-inflammatory factor IL-10 and pro-inflammatory factor IL-6, TNF-α was significantly decreased(P<0. 05), the main immune organ thymus index decreased significantly(P<0. 01), and the spleen index increased significantly(P<0. 05). In feces, the potential beneficial bacteria Akkermansia and Lactococcus were up-regulated after peptide intervention. Taken together, BBP has a potential anti-fatigue effect, which may be achieved by regulating the antioxidant capacity in vivo and the structure of gut microbiome.Keywords：peptides;antifatigue;antioxidant;inflammation;gut microbiome6|11|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the genetic variations related to skeletal muscle development in Tibetan pigs at the whole genome level, this study conducted the whole genome re-sequencing of 5 Diqing Tibetan pigs, and merged with 70 whole genome re-sequencing data in NCBI database of Tibetan pigs from three regions, Xiang pigs with the same body size and growth rates as Tibetan Pigs, and Duroc and Large white with large size and fast growth. After obtaining the whole genome SNP, the genetic differences between Tibetan-Xiang pigs and Duroc-Large white pigs were detected by selective sweep and allele frequency analysis of individuals with confirmed population relationship by population genetic analysis. By integrating genetic differences with GO and KEGG analysis, and previous studies on the transcriptome and proteome of skeletal muscle in Tibetan pigs to identify genes related to skeletal muscle development. The results showed that: 1)A total of 2 211 genes had genetic differences between Tibetan-Xiang pigs and Duroc-Large white pigs, and 138 genes were enriched to GO enrichments and KEGG pathways related to skeletal muscle development; 2)Nine of the 2 211 genes(UCHL3, POSTN, COL12A1, PGK1, JPH1, GPT2, RBFOX1, FLNB and DCX)were transcribed and translated into proteins in the longissimus dorsi muscle of 60 day embryos, one gene of CKM was the DEPs between the two comparison groups of 6-month-old finishing pigs; 3)The 10 genes contained 936 SNPs, of which 655 were located in intergenic region, 255 were intron variations, and a few located in exon and regulatory region. This study identified genetic variations and genes related to skeletal muscle development in Tibetan pigs, which would provide informative insights into further researches for the genetic mechanism of skeletal muscle development in Tibetan pigs.Keywords：Tibetan pig;skeletal muscle;whole genome SNPs;selective sweep;allele frequency2|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The purpose of this study was to investigate the regulatory mechanism of androgen receptor(AR)and co-regulatory factors in the regulation of testosterone on glutathione peroxidase 5(GPX5)in sheep epididymal epithelial cells(EECs). CCK-8 was used to detect the effect of testosterone on the proliferation of EECs. The mRNA levels and protein expressions of AR, GPX5, steroid receptor coactivator 1(SRC-1), cAMP-response element-binding protein(CBP), P300 and Nuclear receptor corepressor 2(NCOR2)were detected by qRT- PCR, immunofluorescence and Western blot; The luciferase activity of EECs after siRNA interference with SRC-1 or P300 was measured by double luciferase reporter gene. The results showed that: 1)Compared with the control group, the expression of GPX5 mRNA and protein in 100 nmol/L testosterone group was significantly increased(P<0. 01), while the expression of GPX5 mRNA and protein in 1 000 nmol/L testosterone group was not significantly different from that in the control group(P>0. 05), but it was significantly(P<0. 01)and significantly(P<0. 05)lower than that in 100 nmol/L testosterone group. The expression of AR in the nucleus was significantly increased(P<0. 05), and the expression of AR mRNA and protein were significantly increased(P<0. 01)and significantly(P<0. 05), respectively. The expression of AR mRNA and protein in 1 000 nmol/L testosterone group was significantly lower than that in the control group(P<0. 05), and the expression of CBP, P300 and SRC-1 protein in 1 000 nmol/L testosterone group increased significantly(P<0. 01), especially in the nucleus. 2)There was no significant difference in the expression of GPX5 mRNA and protein between siRNA-AR group and control group(P>0. 05), while the expression of SRC-1 and P300 protein was significantly higher(P<0. 01). The expression of GPX5 mRNA and protein in pcDNA 3. 1-AR group was significantly higher than that in the control group(P<0. 01)and significantly(P<0. 05). 3)The expression of GPX5 mRNA and protein in siRNA-SRC-1 group or siRNA-p300 group was significantly lower than that in the control group(P<0. 05), and there was no significant difference in the expression of AR protein between siRNA-SRC-1 and siRNA-p300 groups and the control group(P>0. 05), the transcriptional activity of AR in siRNA-SRC-1 and siRNA-p300 groups decreased significantly(P<0. 05). In conclusion, testosterone has a concentration dependent regulatory effect on the expression of GPX5, AR and coregulators in sheep EECs. Testosterone regulates the expression of GPX5 through AR and its coregulators SRC-1 and p300/CBP. This study provides a theoretical basis for exploring the regulation mechanism of GPX5 in epididymis.Keywords：epididymal epithelial cells;glutathione peroxidase 5;testosterone;androgen receptor;coregulators0|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the two important economic traits of the Jining grey goat, birth weight and mortality, the descriptive statistics, least squares analysis of variance and covariance analysis were performed using SPSS 19. 0 and SAS 9. 2 software. The effects of five factors, birth year, birth season, breeding season, sex, and lambing type, on the birth weight and mortality of Jining grey goat lambs were analyzed based on the lambing records from 2012 to 2017. The least square mean of birth weight and mortality of lambs was obtained. The results showed that: 1)The birth year, birth season, sex and lambing type had a very significant effect on lamb birth weight(P<0. 01); Lambing type had a significant effect on lambs mortality(P<0. 05), while the breeding season had a very significant effect on lamb mortality(P<0. 01). 2)From 2012 to 2017, the birth weight of lambs first decreased, then increased and finally decreased. With the increase in lamb birth weight, the mortality showed a trend of first decreasing and then increasing. 3)The birth weight of male lambs was significantly higher than that of female lambs(P<0. 01). 4)Mortality increases with the increase in lambing number of ewes. The birth weight of single lamb was significantly higher than that of four lambs and above(P<0. 01), and the birth weight of double lambs was significantly different from that of three lambs(P<0. 05). 5)The birth weight of lambs born in autumn was significantly higher than that in other seasons. The birth weight of lambs produced in spring was significantly higher than that in summer and winter(P<0. 05). In conclusion, the birth weight and mortality of Jining grey goats are affected by five factors including birth year, birth season, breeding season, sex and lambing types. The study provides a scientific basis for improving the birth weight and reducing the mortality of lambs by strengthening management in the future, as well as the estimation genetic parameters and breeding values in the next step. It also provides a certain theoretical basis for improving the production performance of the Jining grey goat and the selection and breeding of high-quality Jining grey goat.Keywords：Jining grey goat;birth weight;mortality;influencing factors1|10|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the effects of embryo egg injection of 25-OH-D3 on hatchability, 1 to 7 days growth and serum biochemical indexes of ducklings, 200 60-week-old cherry valley duck eggs were randomly divided into 5 groups, with 8 replicates for each group and 5 hatching eggs for each replicate. On the 13. 5th day of incubation, no treatment for group A, while group B was injected with 0. 2 mL 0. 85% normal saline, group C, D and E were injected with the same volume of 25-OH-D3 solution with different concentrations. After shelling, the basic diet was fed for 7 days. The hatching rate of each group was calculated, and the body weight and serum biochemical indexes were measured. The results showed that: 1)Compared with group A, the hatchability of ducklings in groups C, D and E increased by 4. 79%, 5. 54% and 3. 37%, respectively(P<0. 05). Group C, D and E had no significant effect on the bodyweight of 1-day-old and 7-day-old ducklings(P>0. 05). The weight of 3-day-old ducklings in group D increased significantly by 13. 19%, the weight of 1-day-old ducklings in group D increased significantly by 1. 65%(P<0. 05). 2)Compared with phase A, groups C, D and E had no significant effect on the development of tibia of ducklings(P>0. 05). 3)Compared with group A, the levels of growth hormone and insulin-like growth factor I in serum of ducklings in groups C, D and E were significantly increased(P<0. 05). The levels of 25-hydroxycholecalciferol in serum of ducklings in groups D and E increased by 56. 16% and 40. 16%, respectively(P<0. 05). The level of serum phosphorus of ducklings in group C increased by 22. 20%(P<0. 05). 4)Compared with group A, groups C, D and E significantly reduced the levels of LDL in serum of duckling(P<0. 05). Group C significantly increased the content of ALB in the serum of duckling(P<0. 05). Group D significantly increased the activity of ALP and GLU in serum of duckling(P<0. 05)while group E significantly decreased the activity of ALP and AST in serum of duckling(P<0. 05). Group C and D significantly increased the activity of AST in serum of duckling(P<0. 05). Therefore, the injection of 25-OH-D3 into the embryo egg could improve the hatchability and immunity of ducklings, . The optimal additive amount is 0. 8 μg/piece, and promote early growth and development, and provide a better foundation for later development. These results suggest that the injection of 25-OH-D3 in ovo is beneficial to the development of ducklings, and plays a potential positive role in the health of ducklings.Keywords：cherry valley ducklings;25-hydroxylcholecalciferol;in ovo injection;early development2|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To solve the problem that the quality change of golden pompano(Trachinotus ovatus)is difficult to predict during storage, TVB-N mass fraction(w(TVB-N)), total viable counts, K value and sensory assessment were investigated and Radial Basis Function Neural Network(RBFNN)and Back Propagation Neural Network(BPNN)prediction models were established. Residual analysis and relative error analysis were taken to evaluate and compare the accuracy of the models. The results showed that: 1)The residuals of BPNN model and RBFNN model were random and irregular, indicating that both models were suitable for predicting the freshness of golden pompano fillets, the absolute value of residuals of RBFNN model was smaller; 2)For the quality indicators of golden pompano fillets stored at 4 ℃, the absolute value of relative error predicted by BPNN model was less than 15%(except for the 0th day of K value), and the absolute value of relative error predicted by RBFNN model was mostly less than 5%, the absolute value of relative error predicted by RBFNN was smaller. For the prediction of the freshness of golden pompano fillets, the RBFNN model was more accurate, while the BPNN model was less accurate. Therefore, the RNFNN model is more suitable for predicting the storage quality of golden pompano.Keywords：golden pompano;storage;quality change;neural network prediction model3|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The effects of different ventilation modes on the indoor humidity and heat characteristics of solar greenhouse were studied. A numerical simulation model of crop environment moisture heat system in solar greenhouse was established by using computational fluid dynamics numerical simulation method. The comparison of simulation results with experimental results shows that the maximum relative errors of the simulated and measured values of temperature and relative humidity are 4. 7% and 4. 1%, respectively, which verifies the accuracy of the model. The model is then applied to simulate the air flow and temperature and humidity distribution in the warm room under different ventilation modes, and the effects of different ventilation modes on the indoor humidity and heat characteristics are compared and analyzed. The results show that: Different ventilation modes affect the movement track and velocity of indoor air flow, thus affecting the distribution of indoor temperature and relative humidity. When only the upper vent is opened for ventilation, the indoor average temperature and relative humidity are high, the climate distribution is uniform, and the overall change is small, which is suitable for the ventilation requirements in winter and spring or when the indoor temperature and humidity are low in the early morning and evening; When only the lower vent is opened for ventilation, the indoor temperature and humidity distribution pattern is the worst. The temperature and humidity at the air inlet is significantly lower than the north wall, and there is vortex at the inlet, which is not conducive to the growth and development of crops; When the upper and lower vents are only half open for ventilation, the average temperature and relative humidity of the crop area are 39. 3 ℃ and 25%, respectively. When the upper and lower vents are fully open, the average temperature and relative humidity of the crop area are 36. 8 ℃ and 23. 7%, respectively. Compared with the former, the indoor temperature and relative humidity of this mode are significantly reduced, which is suitable for the cooling and dehumidification requirements in the solar greenhouse in summer or hot weather.Keywords：solar greenhouse;computational fluid dynamics;microclimate;window opening mode;porous medium6|11|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The test method of intermittent micro-sprinkling irrigation was used to address the problem of micro-sprinkling hose blockage during irrigation with sandy water. Sediment mass concentration, working pressure and micro-sprinkling hose structure were selected as the test factors, average relative flow, flow uniformity of orifice group and flow drop of orifice group were used as the evaluation indexes of the clogging degree of the micro-sprinkling hose. The blockage condition and the position of the micro-sprinkling hose were analyzed, and the influence process and mechanism of the working pressure and the sediment mass concentration of the sandy water on the blockage of the micro-sprinkling were studied. The results show that: 1)Among the four types of micro-sprinkling hoses(the folded diameter of 45, 45, 48 and 60 mm, respectively; and the number of orifices in the single circulating orifice group of 3, 5, 5 and 5, respectively), the clogging degree of two types of micro-sprinkling hoses with the folded diameter of 45 mm was relatively light, while the maximum sediment mass concentration of 1. 5 g/L, the average relative flow rate of the micro-sprinkling hose with the single circulating orifice group of 5 orifices was only 87. 14% to 96. 19% of that of clear water. 2)When the working pressure was 30 and 40 kPa, the micro-sprinkling hoses were prone to full blockage. When the working pressure was 50 and 60 kPa, the micro-sprinkling hoses were mostly blocked locally. 3)After 10 times of irrigation, the most serious part of the micro-sprinkling hose blockage occurred in the tail, followed by the head. In summary, among the four types of micro-sprinkling hoses, the micro-sprinkling hose with the folded diameter of 45 mm and a single circulating orifice group of 5 orifices had the best anti-clogging performance. The interaction between the working pressure of the micro-sprinkling hose and the sediment mass concentration of the sandy water affected the blockage degree of the micro-sprinkling hose. The working pressure should be reasonably selected when using different sediment mass concentration water sources for irrigation.Keywords：micro-sprinkling hose;working pressure;sediment mass concentration;path analysis3|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the core collection database of the Web of Science(WoS), this study conducted a bibliometric analysis(number of publications, references and keywords)to explore the research progress(degree of attention, knowledge base and research frontiers)on remediation of chromium-contaminated soil by literature co-citation, keyword co-occurrence and burst detection. The results show that a total of 1 972 papers in this research filed are published and the annual publication is on the rise overall, indicating that this field is receiving more and more attention. Literature co-citation analysis showed that the knowledge base in this field mainly includes the following aspects: Biochemical reaction of chromium in soil under natural conditions(environmental biochemistry); Reduction of iron-containing substances(iron compound and nanoscale zero-valent iron); Reduction of organic substances(functional group and biochar); Chromium stress(chromium-resistant bacteria, phytotoxicity and Cr stress); Bioremediation. At the same time, microbial remediation, phytotoxicity and nanoscale zero-valent iron are also the research frontiers in this field and should be focused on. This study provide reliable theoretical basis for further research and practical application in this field.Keywords：chromium;soil remediation;bibliometrics;CiteSpace14|11|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to explore the effect of soil salt content and fertilizer application rate on the nutrient supply of soil solution. Taking soil conductivity as the research object, this study conducted soil column tests under 48 working conditions(S1 to S48)of 3 soil salt content, 4 designed water contents and 4 concentrations of K2SO4 solution. The 5TE sensor was used to continuously observe the soil water content and conductivity. The effects of soil salt content and fertilizer concentration on soil conductivity at different water contents were analyzed. The results showed that: When the soil salt content was high, the high salinity affected the relationship between the dielectric constant ε and the water content θ, resulting in a high water content measured by 5TE. The salinity index was defined as the change rate of soil conductivity σb with volumetric water content θ. The water content θ was corrected by the salinity index X′s, and the accuracy of the corrected water content reached ±2%. When the soil was wetted by a solution with a conductivity of 0 mS/cm(not fertilized), the initial salinity index X′si was not zero indicating that the soil itself would dissolve some nutrients. When the soil nutrients were sufficient, the contribution of the soils own background value to the conductivity could not be ignored. Therefore, in the process of fertilization, full consideration of the difference in soil salt content and rational fertilize soil should be conducted to avoid the low utilization rate of soil nutrients and waste of fertilizer caused by blind fertilization.Keywords：soil conductivity;salinity index;volumetric water content;conductivity of wetting solution;soil salt content;fertilizer concentration7|13|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To reveal the spatial and temporal evolution of yield per unit area of cultivated land in the black soil area of northeast China, this research takes counties as the evaluation unit, based on the research perspective of temporal changes, spatial evolution, and regional differences, and uses NPP statistical values and convert them into yields to explore the temporal, spatial and regional change characteristics of yields in both the whole black soil region of the northeast and each county from 2000 to 2020. The results showed that: 1)From 2000 to 2020, the per unit area yield of cultivated land in the whole northeast black soil region showed a fluctuating upward trend in time sequence, which increased by 0. 79 t/hm2 in total. The number of low, medium and high per unit area yield counties decreased and the number of higher per unit area yield counties increased, and the internal variation of cultivated land yields remained basically unchanged. 2)The spatial variation of cultivated land yield in different counties of the northeast black soil region was in an obvious non-equilibrium state. The low per unit area yield counties were distributed in the southwestern part of the black soil area, the middle yield counties were concentrated in the western part of the black soil area, and the higher yield counties were distributed in the northwestern, northeastern, and southern parts of the black soil area, and the high yield counties were distributed in the southeastern part of the black soil area. 3)According to the regional yield and terrain fluctuation, it showed that the yield in the northeast black soil area was influenced by the topographic relief, and the areas with high values of relief were consistent with the areas with high values of county yield. In conclusion, the research framework and results are of positive significance for the improvement of per unit area yield of counties.Keywords：cultivated land yield;remote sensing accounting;spatial and temporal variability;cultivated land;the black soil area of northeast China3|10|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To achieve rapid estimation of soil organic carbon content in the lakeshore oasis of Bosten lake, both the soil hyperspectral data and soil organic carbon data measured were combined, the soil spectral data were preprocessed by continuous wavelet transform(CWT). The feature bands screened by correlation coefficient analysis(CC), continuous projection algorithm(SPA), competitive adaptive reweighted sampling(CARS), and genetic algorithm(GA)methods were used in modeling. A random forest(RF)model was constructed using the feature bands screened by continuous projection algorithm(SPA), competitive adaptive reweighted sampling(CARS)and genetic algorithm(GA). The results showed that: The average soil organic carbon content in the study area decreased from 12. 36 g/kg to 10. 49 g/kg with the increasing of soil depth The average coefficient of variation was 69. 62% displaying strong spatial heterogeneity. The continuous wavelet transform effectively improved the correlation between soil organic carbon content and spectral reflectance at different soil depths, and the average value of correlation coefficient at different soil depths increased by 22. 41%. The accuracy of the model constructed by continuous wavelet transform of spectral data was significantly improved, and the RF model validation set R2 and RPD were improved by 7. 09% and 10. 06% on average, respectively. CC, CARS, SPA and GA algorithms eliminated the redundancy of spectral information and effectively reduced the input and RMSE values of the CWT-RF model. The characteristic bands screened at soil depths of 0-20, 20-40, 40-60 and 60-80 cm were compressed to 8. 51%, 5. 38%, 2. 21% and 3. 67% of the full spectral number on average, respectively. The RMSE values were reduced by 111. 67%, 135. 61%, 12. 25%, 74. 96% on average, which effectively improved the modeling rate and model accuracy. In conclusion, the CWT-SPA-RF model was the best for estimating the organic carbon content of 0-80 cm soil in the lakeside oasis, with the constructed model validation set R2≥0. 77, RMSE≤3. 06 g/kg and RPD≥2. 07.Keywords：soil organic carbon content;soil hyperspectral data;continuous wavelet transform;random forest;characteristic band screening;lakeside oasis5|13|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the spatial and temporal evolution characteristics of rural settlements Donghai County, Jiangsu Province is taken as an example. Based on the rural settlement map data of the study area in 1990, 2000, 2010 and 2020, this study measured and evaluated the spatial and temporal change characteristics of rural settlement sites in the study area and their evolution mechanisms by using landscape pattern index, standard deviation ellipse, kernel density, accessibility and spatial autocorrelation analysis. The results showed that: 1)The total and average area of rural settlements in Donghai County from 1990 to 2020 showed a trend of increasing year by year, and the number of settlement patches gradually decreased along with the gradual increase of the total area of settlements; The rural settlements in the study area have undergone the process of “point-like an increasing block-like increase and decrease, ” and “point and belt-like simultaneous small increase”. The changes of the rural settlement were mainly pointed changes and block changes, among which block changes were mainly distributed around the county urban area and established towns. 2)The basic spatial pattern of rural settlements in Donghai County was relatively stable, maintaining a “W to E” directional distribution. In terms of direction, the center gravity of rural settlements in the study area has undergone a directional shift of “Northeast-South-North” from 1990 to 2020. 3)From 1990 to 2020, the changes of rural settlements in Donghai County changed from a period of slow change to a period of rapid fluctuation and then entered a period of stable development, and the overall trend was coordinated development. 4)From 1990 to 2018, the change of rural settlements in Donghai County was influenced by the accessibility of towns, transportation and water sources less than 15 min. With the improvement of rural economic development and the modernization of rural lifestyle, rural settlements tended to expand closer to towns and transportation routes, and the proximity to towns, roads and water became the main influencing factors of rural settlement changes during this period. 5)Most of the townships in Donghai County displayed insignificant changes in the number of the rural settlements, and are characterized by random spatial distribution of farmers' self-organized housing construction. Most of the townships in the study area had no significant spatial autocorrelation, and there was no area with the strongest significance. The results of the study can provide a reference for the optimal spatial allocation of rural areas and the promotion of rural revitalization by classification.Keywords：rural settlement;kernel density analysis;standard deviation ellipse;accessibility;Donghai County8|13|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the impact of agricultural machinery services on agro-ecological efficiency. based on China's provincial panel data from 2004 to 2019, this study used the variable return-to-scale non-expected super-efficiency SBM model to measure China's agricultural ecological efficiency. The two-way fixed-effect model and double-fixed space Durbin model were also adopted to analyze how machinery services influence agro-ecological efficiency in local and other regions. The result show that: China's agricultural ecological efficiency has shown a fluctuating downward trend in recent years, the ecological level in the eastern region is relatively high, and the central and western regions are relatively lagging; There is a positive correlation between agricultural machinery services and agricultural ecological efficiency, and agricultural machinery operation services have a positive impact on agricultural ecological efficiency. The direct effect, indirect effect and total effect are 0. 006, 0. 017 and 0. 024, respectively. The indirect effect accounts for about 75% of the total effect, indicating that the impact of productive services on agro-ecological efficiency will be systematic and the development of agricultural machinery services will play the key role in promoting high-quality agriculture in China.Keywords：agricultural machinery services;agro-ecological efficiency;spatial spillover;double fixed-space Doberman model3|9|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the characteristics of farmland abandonment and intergenerational heterogeneity of farmers in mountainous areas, this study constructs an analysis framework for intergenerational differences in farmland abandonment behavior of farmers in mountainous areas based on the “social cohorts” theory in intergenerational sociology, and conducts an empirical test by using Logit model and Tobit model based on the micro-data of Yudu County in southern Jiangxi Province. The results indicate that: 1)There is an obvious intergenerational difference in the farmland abandonment behavior of farmers in mountainous areas, and the farmland abandonment behaviors of the old, middle and new generations increase successively. Specifically, for each level of intergenerational differences, the probability and degree of farmland abandonment increased by 6. 6% and 2. 3%, respectively. 2)The intergenerational differences have mechanism that affect farmers' farmland abandonment behavior in mountainous areas through acting on their farmland conservation intentions, livelihood strategies and planting structures. The old, middle and new generations of farmers in mountainous areas are less willing to protect farmland, more willing to transform their livelihood strategies to non-agricultural, and less willing to plant cash crops, which leading to an increase in their farmland abandonment behavior in turn. Therefore, it is suggested to reform the current agricultural management system and optimize the agricultural production mode of farmers of different generations, optimize the allocation of farmland between generations of farmers to improve the efficiency of farmland use, as well as build the industrial chain of cash crops in mountainous areas according to local conditions to promote the common income increase of farmers of different generations.Keywords：farmland abandonment;farmers behavior;social cohorts;intergenerational differences;mountainous areas of south Jiangxi19|9|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the impact of the use of digital finance on farmers' happiness, from the perspective of a farmer entrepreneurial intermediary, this study used the 2019 China Household Finance Survey(CHFS)and Oprobit model to investigate the impact of digital financial use on farmers' happiness. On this basis, this study used a mediating effects model to analyze the mechanism of the role of entrepreneurship between the use of digital finance and farmers' happiness, and used the Oprobit model to analyze digital finance heterogeneity and cohort differences in the impact of digital finance on farmers' happiness. The results show that: The use of digital finance can significantly enhance farmers' happiness. Entrepreneurship plays a part in mediating the effect of digital finance use on farmers' happiness, and promoting farmers' entrepreneurship is an important way for digital finance to improve farmers' happiness. Digital payments contribute most to farmers' happiness than digital finance and digital credit. In conclusion, using digital finance is most beneficial to improve the happiness of farmers who are female, married, over the age of 60 or with low education.Keywords：digital finance;farmers;happiness;Oprobit model;intermediary effect;entrepreneurship2|10|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the relationship between internet application and rural resident service adoption behavior, based on the three-phase panel data of CFPS, XT-Probit model, CMP estimation method and mediation effect model are used to examine the impact of Internet application on rural residents' service adoption from the aspects of production and life. The results show that: 1)The influence coefficients of internet applications on productive service and life service are significantly positive, indicating that internet applications can jointly promote rural resident service adoption behavior from production and life; 2)Internet application has a greater role in boosting the adoption of productive and life services by rural residents of young and middle-aged, higher education level, or non-plain-area. The promotion effect on the adoption of productive service by the middle- and low-income rural residents is greater, and the promotion of the adoption of life service by the middle- and high-income rural residents is greater; 3)Internet application jointly improved the rural residents' level of service adoption by expanding information channels and promoting non-agricultural employment, and the former has a greater mediating effect on life service, while the latter has a greater mediating effect on productive service. Therefore, establishing a digital rural service platform, cultivating digital village services with regional characteristics, and implementing “Internet+” rural labor training are important means to support the development of the rural service industry.Keywords：rural resident service;internet application;productive service;life service0|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the impact of the improvement of China's rural transport infrastructure on the misallocation of agricultural factors and improve the efficiency of agricultural factor allocation, this study calculated and visualized the misallocation coefficients of agricultural labor factor, land factor and machinery factor in 31 provincial-level areas in China(Data did not include those of Hong Kong, Macao and Taiwan regions. The same below. )from 2000 to 2020 based on the production theory. The spatial Durbin model was used to analyze the impact of rural transport infrastructure improvement on the misallocation of agricultural factors and the adjustment effect of arable land slope. The results showed that: There were space-time differences in the misallocation of agricultural factors in China, and the excessive and insufficient allocation coexisted. The improvement of rural transport infrastructure had a restraining effect on the misallocation of agricultural labor factor, land factor and machinery factor. The rural transport infrastructure had a spatial spillover effect, and the transport infrastructure in surrounding areas also affected the misallocation of local agricultural factors. In addition, the slope of arable land significantly adjusted the impact of rural transport infrastructure on the misallocation of agricultural factors. In conclusion, this study demonstrated the importance of rural transport infrastructure construction from the perspective of resource allocation, and also provided ideas and support for alleviating the misallocation of agricultural factors.Keywords：countryside;transport infrastructure;factors misallocation;space-time characteristics;arable land slope;ArcGIS;spatial Durbin model6|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
