Please wait a minute...
Early Edition
Table of Content
28 April 2023, Volume 41 Issue 2
For Selected: View Abstracts Toggle Thumbnails
  • "Pine Cedar and Cypress" Special Topic
    Effects of Different Gap Sizes of Pinus massoniana Plantation on Plant Diversity and Soil Physicochemical Properties in the West China Rain Zone
    ZENG Hong, WU Yuru, ZHONG Xinyi, XU Yin, YU Shunyao, LIN Jingyun, WEI Junde, HAOjianfeng
    2023, 41(2):  185-192.  doi:10.16036/j.issn.1000-2650.202301189
    Abstract ( 675 )   PDF (11245KB) ( 281 )   Save
    References | Related Articles | Metrics
    【Objective】 This study aims to reveal the relationship between plant diversity and soil physicochemical properties in Pinus massoniana plantation under different gap sizes. 【Method】 In this study, five different gap sizes (50-100、100-150、200-250、400-450、600-650 m2) in a 25-year-old P. massoniana plantation were taken as research objects, were compared with pure stand of P. massoniana. This study investigated and analyzed the vegetation composition, species diversity and soil physicochemical properties under different gap sizes suing Redundancy analysis (RDA) to determine the relationship between soil factors and species diversity. 【Result】 ① The important values of native tree species, such as Quercus serrata, Acer davidii, Eurya japonica, and Mallotus tenuifolius, were at the forefront in different forest gap sizes. The increase in the gap size led to an increase in the number of shade-tolerant species, while the number of semi-shade-tolerant species remained stable and occupied an important position. ② The G4 (400-450 m2) gap size showed the highest species diversity, and there was a strong positive correlation between species richness and diversity index of shrub layer and soil physicochemical properties. ③ The soil physicochemical properties under the middle and large forest gaps were obviously improved compared with those under the small forest gaps. The soil contents under G4 gap size showed of the highest content of total potassium (45.41 mg/kg), available potassium (191.29 mg/kg) and organic matter (68.42 mg/kg). The content of available potassium was significantly higher than that of other gaps (P<0.05). Soil organic matter, soil total nitrogen and soil total potassium were the main environmental factors that affect the distribution of species under the forest gaps of P. massoniana plantation. 【Conclusion】 The results showed that plant diversity could sustain and even improve soil fertility, and G4 gap size (400-450 m2) was the most beneficial to plant community regeneration and soil nutrient cycling in this area.
    Effects of Changes in Soil-Based Properties on Soil Respiration in Pinus yunnanensis in Central Yunnan under Nitrogen Deposition
    LIANG Yangsen, WANG Keqin, SONG Yali, ZHENG Xingrui, HU Chun
    2023, 41(2):  193-202.  doi:10.16036/j.issn.1000-2650.202211185
    Abstract ( 359 )   PDF (5906KB) ( 134 )   Save
    References | Related Articles | Metrics
    【Objective】 The current study was conducted to study the effects of changes in soil physicochemical properties, microbial characteristics and enzyme activities on soil respiration in wet and dry seasons under the background of nitrogen deposition, and to provide scientific basis for carbon cycle and material cycle and energy flow in subtropical forest ecosystems. 【Method】 The alpine Pinus yunnanensis in Central Yunnan were selected for the study. Soil physicochemical properties, enzyme activities, soil microbial population, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and soil respiration under simulated N deposition (CK 0 g/(m2·a), low N LN 10 g/(m2·a), medium N MN 20 g/(m2·a), high N HN 25 g/(m2·a)) in wet and dry seasons were investigated in this study to elucidate the seasonal variation of soil respiration under N deposition and the response relationship between soil respiration and soil properties, and to explore the relevance of the coupling mechanism. 【Result】 ① Soil TN and NH4+-N were significantly increased under all N treatments compared to CK. ② During the wet-dry season, urease was significantly increased by 16.38%-67.95% in HN; sucrase was significantly decreased by 19.65%-35.65% in HN; catalase was significantly increased by 11.11%-100.00% in LN, MN, and HN; while polyphenol oxidase was significantly decreased in MN, HN by 8.69%-25.00%, compared to CK.③Compared to control, soil microbial population and MBC was significantly increased in LN, MN (4.70%-30.52%) but significantly decreased in HN (18.57%-57.20%); MBN was significantly decreased in HN (6.80%-13.70%).④N deposition promoted soil respiration in the wet season, however HN inhibited soil respiration in the dry season; across the tested period, HN changed from promoting to inhibiting effect on soil respiration. Soil respiration was significantly correlated with soil temperature and moisture; Q10 of LN, HN increased by 7.41%, 60.27%, respectively.⑤In the wet season, soil respiration was significantly and positively correlated with TN, TP, TK, NH4+-N, NO3--N, and urease, but was significantly and negatively correlated with sucrase, polyphenol oxidase, microbial population, MBC, and MBN; in the dry season, soil respiration was significantly and negatively correlated with NO3--N and urease, but was significantly and negatively correlated with peroxidase, polyphenol oxidase, microbial population, MBC, and MBN. 【Conclusion】 HN suppressed soil respiration in P. yunnanensis forests over time, and N application did not change the seasonal and daily patterns of soil respiration.
    Potential Distribution of Pinus sylvestris in Inner Mongolia Autonomous Region Based on MaxEnt Model
    SONG Huifang, DANG Xiaohong, GAO Yong, MENG Zhongju, SUN Yanli
    2023, 41(2):  203-208.  doi:10.16036/j.issn.1000-2650.202211193
    Abstract ( 341 )   PDF (4035KB) ( 116 )   Save
    References | Related Articles | Metrics
    【Objective】 This study aimed to optimize the layout of the existing planting area of Pinus sylvestris and identify suitable planting areas for future introduction and extension of planting scientifically. 【Method】 This paper used environmental factors and geographical distribution data, combined with ArcGIS and MaxEnt model, to predict the dominant environmental factors and potential geographical distribution of P. sylvestris. 【Result】 ① In the simulation of potential habitat of P. sylvestris, the MaxEnt model has a high accuracy with AUC=0.821. ② Precipitation in the wettest month (BIO13), isotherm (BIO3), mean temperature of wettest quarter(BIO8)and mean temperature of driest quarter(BIO9) were the most important environmental factors affecting the distribution of P. sylvestris. ③ The total suitable growing area of P. sylvestris in the study area is 86.997 8 km2, with the highly suitable area being 30.811 7 km2, which is 25.76% of the total Inner Mongolia area. These highly suitable areas were mainly distributed in Hulunbuir, Xing′an League, Xilin Gol League, Chifeng and Hohhot. 【Conclusion】 This study suggests that the potential distribution of P. sylvestris is the widest in northeast China, with climate being the main influential factors for the distribution. These results provide a basis for strengthening the construction of windbreak and sand fixation forests of P. sylvestris in different regions.
    Biomass Allocation and Allometric Growth of Pinus yunnanensis Seedings of Different Classes
    CHEN Shi, CHEN Lin, TANG Junrong, CAI Nianhui, XU Yulan, HUANG Jian
    2023, 41(2):  209-216.  doi:10.16036/j.issn.1000-2650.202209186
    Abstract ( 389 )   PDF (1568KB) ( 189 )   Save
    References | Related Articles | Metrics
    【Objective】 The individual differentiation of Pinus yunnanensis was strong during seedling period, and the phenomenon of slow growth was obvious, which seriously prevented the process of improved varieties of P. yunnanensis. The biomass investment, distribution and allometric growth of P. yunnanensis seedlings with different levels were studied in order to deeply understand the effect of individual size on adaptation strategies derived from the biomass allocation of P. yunnanensis seedlings. 【Method】 The growth and biomass traits of 425 P. yunnanensis seedings around 3-years-old from the same provenance were investigated. One-way ANOVA was used to compare the differences in biomass investment and allocation of seedlings at different seedling levels, and the allometric growth was analyzed by adopting standardized major axis (SMA) analyses. 【Result】 The biomass investment and allocation were different for seedlings at different levels. The biomass investment in each component was ordered by leaf > stem > root. The lower level the seedlings, the less biomass the investment, and the more obvious the differentiation, but the more biomass was allocated in root. With the increase of seedling level, the aboveground part biomass increased. There were significant or extremely significant allometric or isokinetic growth relationships among the components of P. yunnanensis seedlings at different levels , as well as the correlation between the components and individual plant. The allometric growth indexes of root-leaf, stem-leaf and non-photosynthetic organ-leaf were significantly different among different seedling levels. With the individual size increasing, the allometric growth characters between stem, leaf or non-photosynthetic organs and individual biomass changed significantly, with different SMA slopes. There were significant or extremely significant allometric relationships between seedling height and ground diameter, individual plant, root-shoot ratio, and between diameter and individual plant, ground diameter and root-shoot ratio of different seedling levels. The growth rate of morphological indexes was lower than the accumulation rate of underground biomass and individual biomass. 【Conclusion】 The allocation mode of P. yunnanensis seedlings at different levels did not show a same trend. The high level P. yunnanensis seedlings adopted the adaptive strategy of improving the resource utilization efficiency, while the low level P. yunnanensis seedlings adopted the survival strategies of improving the survival rate, of which corresponding components balanced the allocation of biomass by accelerating growth.
    Effects of Different Nitrogen Forms and Ratios on Photosynthetic Characteristics and Growth in Cunninghamia lanceolata and Schima superba Seedlings
    WANG Lidong, LIANG Haiyan, WANG Yanru, QUAN Xiaoqiang, LI Xiaoyu, YAN Xiaoli
    2023, 41(2):  217-224.  doi:10.16036/j.issn.1000-2650.202211183
    Abstract ( 462 )   PDF (7143KB) ( 87 )   Save
    References | Related Articles | Metrics
    【Objective】 The study purposes to investigate the optimal ratios of ammonium to nitrate suitable for the main coniferous tree, Cunninghamia lanceolate, and broad-leaved tree, Schima superba, so as to improve the productivity and nitrogen use efficiency for the broadleaf-conifer mixed forests in subtropical zone. 【Method】 In this study, seedlings were cultured under five ratios (10∶0, 0∶10, 7∶3, 3∶7, 5∶5) of NH4+-N to NO3--N and the photosynthetic characteristics, seedling growth, biomass and corresponding distribution were measured and compared for the two species. 【Result】 The ammonium-nitrate ratio of 5∶5, 7∶3 and 3∶7 in treatments increased the net photosynthetic rate, transpiration rate, stomatal conductance, biomass and seedling height of both C. lanceolata and S. superba, compared to the ratio of 10∶0 and 0∶10 in treatments of single N form. Higher ammonium concentration significantly increased the net photosynthetic rate, seedling height, ground diameter and biomass of C. lanceolata, while treatments of higher nitrate N concentration increased the net photosynthetic rate, seedling height, ground diameter and biomass of S. superba. Higher ammonium concentration reduced the root-shoot ratio of C. lanceolata, indicating promoting the growth of C. lanceolata aboveground part. Higher nitrate N concentration reduced the root-shoot ratio of S. superba, indicating promoting the growth of S. superba aboveground part. 【Conclusion】 Different nitrogen forms and ratios significantly affected the photosynthesis and growth of C. lanceolata and S. superba. The mixed treatment with the same proportion of ammonium and nitrate is most beneficial to the photosynthesis, seedling height growth and biomass accumulation of C. lanceolata, and the mixed treatment with higher concentration of nitrate N is most beneficial to the photosynthesis and biomass accumulation of S. superba. In the seedling cultivation and mixed afforestation with the two tree species, we can apply ammonium N to C. lanceolata and nitrate N to S. superba according to the situation of N in the soil.
    A Study on 13C Distribution Characteristics of Picea asperata and Larix masteriana Seedlings Using Pulse Labeling
    YANG Yuting, YANG Hongyan, LIU Jinchao, QU Weichen, DU Ting, ZHANG Yu, ZHANG Li, YOU Chengming, TAN Bo, XU Zhenfeng, LI Han
    2023, 41(2):  225-229.  doi:10.16036/j.issn.1000-2650.202205178
    Abstract ( 549 )   PDF (1496KB) ( 109 )   Save
    References | Related Articles | Metrics
    【Objective】 The present study was conducted to understand the distribution of photosynthetic carbon assimilation products by conifer species in different organs and the amount of input in the soil. 【Method】 Taking Picea asperata and Larix masteriana as the research objects, four 13C isotope pulse markers were performed on seedlings in the growth stage by combining potting experiments with pulse labeling, in order to reveal the distribution of photosynthetic carbon assimilation products of P. asperata and L. masteriana in organ-soil. 【Result】 After labeling, the δ13C values in each organ and soil of two tree species were significantly different from their initial values, and 13C enrichment ability of two species showed as L. masteriana > P. asperata. The δ13C values of root, branch, leaf and soil in L. masteriana ranged from 25.33‰ to 171.64‰, 36.68‰ to 206.84‰, 79.40‰ to 230.91‰, and -16.49‰ to -11.28‰, respectively, which were specifically manifested as leaf > branches> roots> soil. And the δ13C values of root, branch, leaf and soil in P. asperata ranged from -23.02‰ to 63.97‰, -23.72‰ to 18.52‰, -20.09‰ to 14.09‰, and -20.27‰ to -15.71‰, respectively, which were specifically manifested as roots > leaves > branches > soil. 【Conclusion】 Under the labeling of 13C pulse marking method, the enrichment of L. masteriana 13C is higher than that of P. asperata. The carbon fixation of L. masteriana leaves is higher than that of P. asperata leaves, while the concentration of 13C in P. asperata roots is relatively higher than that of L. masteriana. These results show that pulse labeling is effective in exploring the distribution of photosynthetic products in organ-soil at the seedling stage for conifer species, which provides certain basic data and technical support for the application of stable isotope pulse labeling in plant physiology and ecology.
    Effects of Ectomycorrhizal Fungal Diversity on Biochemical Properties of Spruce Rhizosphere Soil
    ZHANG Chenyang, FU Shuangjia, GAO Haoying, WANG Lixia
    2023, 41(2):  230-239.  doi:10.16036/j.issn.1000-2650.202207187
    Abstract ( 481 )   PDF (3525KB) ( 117 )   Save
    References | Related Articles | Metrics
    【Objective】 This study aimed to explore whether a single above-ground host plant can slow down the decomposition of soil organic matter by reducing the diversity of underground mycorrhizal fungi, and ultimately reducing the availability of soil nutrients. 【Method】 In view of this, ECM fungal communities with different gradients of diversity (1, 2, 4, 8 species of ectomycorrhizal fungi) were inoculated into the sterilized soil of Picea asperata seedlings (collected from the subalpine P. asperata plantation in southwest China), and the control (CK) was also established. After one year, the physical and biochemical properties of the rhizosphere soil were determined. 【Result】 The results showed that the pH value of soil inoculated with four ECM fungi (5.44) was significantly higher than that of control and other treatments (5.21-5.30). The contents of soil organic matter and organic carbon decreased with the increase of ECM fungal diversity (organic matter, 37.62-22.81 g/kg; organic carbon, 21.82-13.23 g/kg). The contents of organic matter and organic carbon in the control were significantly higher than those in the eight ectomycorrhizal fungal inoculation groups (P < 0.05). Inoculation of ectomycorrhizal fungi with different gradients of diversity had no effect on soil total nitrogen or total phosphorus contents. The contents of soil nitrate nitrogen (44.81-64.56 mg/kg), inorganic nitrogen (68.45-87.23 mg/kg), and total dissolved nitrogen (341.28-483.72 mg/kg) increased with the increase in the ECM fungal diversity, except for the inoculation of four species of ectomycorrhizal fungi (nitrate nitrogen, 29.68 mg/kg; inorganic nitrogen, 49.65 mg/kg; total dissolved nitrogen, 181.18 mg/kg), suggesting that these four fungal combinations could facilitate the host-plant to acquire nitrogen, but are not conducive to the activation of nitrogen components from organic matter. 【Conclusion】 The higher the diversity of the ectomycorrhizal fungal community, the stronger the effect on the decomposition of organic matter and the improvement of nitrogen availability. The results can provide data support and a theoretical basis for the role of mycorrhizal fungal diversity in soil ecological function in the southwest Subalpine region.
    Effects of Single Endophytic Fungi and Mixed Endophytic Fungi on Growth and Photosynthesis of Cunninghamia lanceolata Seedlings
    MENG Lei, TANG Zhide, XIE Anqiang, LIN Han, SHEN Wen, JIAN Lingjing
    2023, 41(2):  240-248.  doi:10.16036/j.issn.1000-2650.202212181
    Abstract ( 459 )   PDF (16868KB) ( 79 )   Save
    References | Related Articles | Metrics
    【Objective】 This study purposes to explore the effects of single endophytic fungus and mixed endophytic fungi on the growth and photosynthesis of Cunninghamia lanceolata seedlings. 【Method】 The endophytic fungi isolated from the root, stem and leaf samples of Chinese fir with robust growth and no diseases and insect pests were used as inoculated seedlings. The growth characteristics and photosynthetic physiological indexes of C. lanceolata seedlings were determined by inoculating the single or mixed growth promoting fungi. 【Result】 Four endophytic fungi Trichoderma spirale (S10), Hypoxylon (S22), Colletotrichum gloeosporioides (S24) and Umbelopsis dimorpha (S38) were successfully colonized in the root of C. lanceolata seedlings. Through the analysis of seedling height diameter, aboveground and underground biomass, root to shoot ratio and other growth characteristics, it can be seen that: single strain S24 and mixed strains S10×S22 and S22×S38 significantly promoted the growth of seedling height and ground diameter of C. lanceolata seedlings. Compared with CK group, the growth rates of single strain S24 on seedling height and ground diameter of C. lanceolata seedlings were 2.99% and 15.66%, respectively. The growth rates of seedling height and ground diameter for mixed strains were 13.81% and 3.04%, respectively, for S10×S22, and 18.99% and 11.01%, respectively, for S22×S38. The aboveground and underground biomass growth rates of individual strains S22, S24 and S38 were S22(22.86% and 58.57%)、S24(18.94% and 53.74%)and S38(15.87% and 57.40%), respectively, compared with CK group. By analyzing chlorophyll content, chlorophyll fluorescence parameters (F0Fv/Fm) and other photosynthetic characteristics, it can be seen that: single strain S38 and mixed strains S10×S38 and S22×S24 significantly increased the chlorophyll content of seedlings at 45-60 d stage. Compared with CK group, chlorophyll content of C. lanceolata in S38 and CK group were 11.15%higher. The growth rates of mixed strains were as follows: S10×S38(2.25% and 17.53%)and S22×S24(10.72% and 13.51%). C. lanceolata seedlings inoculated with single strain S24 and mixed strain S22×S38 had a lower F0 value than that inoculated with other strains. The Fv/Fm value ranged from 0.80 to 0.85 across all treatments. 【Conclusion】 These results indicated that both single endophytic fungus and mixed endophytic fungus inoculations significantly improved the biomass and photosynthesis of C. lanceolata seedlings, and could effectively promote the growth of C. lanceolata seedlings. The growth promotion effect of mixed endophytic fungi was stronger than that of single endophytic fungus.
    Effect of Melatonin on Seed Germination and Seedling Growth and Physiological Properties of Keteleeria evelyniana
    ZHOU Dongmei, LI Lianfang, ZHU Cunfu, GU Meng, ZHANG Heyao, LI Xiaojun, LIU Xian, HOU Haixiong, WANG Wenjun
    2023, 41(2):  249-256.  doi:10.16036/j.issn.1000-2650.202209188
    Abstract ( 463 )   PDF (4456KB) ( 96 )   Save
    References | Related Articles | Metrics
    【Objective】 In order to understand the effects of seed soaking with the melatonin on seed germination and seedling physiology of Keteleeria everyniana, this study implemented seed soaking trial with different concentrations of melatonin solution to provide scientific and theoretical basis for seed germination and strong seedling cultivation of K. everyniana.【Method】 A single factor complete randomized experiment design was employed to carry out the trial of seed soaking with different concentrations of melatonin solutions. Seed germination properties were recorded among treatments, and the changes of seedling growth, photosynthetic pigments and enzyme activities were measured. 【Result】 The germination rates, germination potentials, mean germination time, germination index, chlorophyll content, carotenoid content, activities of SOD, POD, CAT and MDA content were 40.4%-60.0%, 14.5%-32.1%, 12.6-14.6 day, 4.2-7.2 seed/day, 0.96-1.43 mg/g, 0.16-0.23 mg/g, 185.4-360.7 U/(g·min), 24.4-64.9 U/(g·min), 1 532.1-1 916.3 U/(g·min) and 9.5-25.6 nmol/g, respectively, with all parameters of the melatonin-treated seeds or seedlings significantly higher than those of control (P<0.05 or P<0.01). 【Conclusion】 Soaking seeds with 0.3 mmol/L melatonin solution was found to be beneficial for seed germination, photosynthetic pigment formation, improving the activities of protective enzymes, and promoting the growth of seedlings, which could be applied to seed treatment of K. everyniana.
    The Root Morphology and C∶N∶P Stoichiometric Characteristics of Cryptomeria japonica var. sinensis Plantations at Different Ages in Rainy Area of Western China
    LI Jing, HONG Zongwen, XIONG Shichen, LI Yu, LIU Xuan, LI Dongqing, LI Han, TAN Bo, XU Zhenfeng, YOU Chengming
    2023, 41(2):  257-265.  doi:10.16036/j.issn.1000-2650.202205182
    Abstract ( 441 )   PDF (2506KB) ( 135 )   Save
    References | Related Articles | Metrics
    【Objective】 This study aims to reveal the difference of root morphology and carbon(C), nitrogen(N)and phosphorus(P)stoichiometry characteristics of roots at different orders for tree at different growth stages. 【Method】 Taking the Cryptomeria japonica var. sinensis plantations of middle-aged forests(13 a), mature forests(33 a)and over-mature forests (53 a)in Rain Area of Western China as the research objects, this study compared and analyzed the root morphology and root function modules of 1-5 grades of C. japonica var. sinensis plantations at different ages. 【Result】 ①With the increase of stand age, the average diameter of grade 1-5 fine roots increased first and then decreased, the specific root length decreased first and then increased, and the specific surface area decreased gradually, while the root tissue density showed no obvious change. With the increase of root order, the average fine root diameter of the same stand age increased, while the specific root length and specific surface area decreased gradually.②With the increase of stand age, the carbon content of C. japonica var. sinensis fine roots as a whole showed a trend of increasing first and then decreasing, the P content, C/N ratio, and C/P ratio showed a trend of decreasing first and then increasing, and the N/P ratio did not change significantly. Moreover, the N content of the absorptive root was higher than that of the transportive root, while the carbon content, C/N ratio, and C/P ratio of the transportive root were all higher than the absorptive root.③The carbon content of fine roots was significantly negatively correlated with phosphorus content, but was significantly positively correlated with the C/N ratio and C/P ratio. The N content was significantly positively correlated with P content, N/P ratio, specific root length and specific surface area, and was significantly negatively correlated with C/N ratio, C/P ratio, diameter and tissue density. 【Conclusion】 In summary, the fine root morphology and stoichiometry of C. japonica var. sinensis plantation have strong plasticity at different growth stages and root orders. The results of the study are helpful for in-depth understanding of the strategy of forest resource absorption and nutrient balance, and can provide a theoretical basis for the sustainable management and operation of plantations.
    Crop Science·Horticulture·Ecology
    Effects of Field Configuration of ′Increasing the Number of Seedlings Per Hill with Reduced Number of Hills′ on Rice Canopy Structure and Light Energy Distribution Characteristics of Indica Hybrid Rice in the Southwest China
    LI Bo, YUAN Yujie, HE Chenyan, ZHOU Xing, LI Qiuping, ZHU Youyun, HE Yuxin, HUANG Xiaofan, AI Xiaofeng, CHEN Yong, ZHOU Wei, CHENG Hong, WANG Li, XIAO Hong, REN Wanjun, DENG Fei
    2023, 41(2):  266-274.  doi:10.16036/j.issn.1000-2650.202207161
    Abstract ( 1682 )   PDF (6973KB) ( 84 )   Save
    References | Related Articles | Metrics
    【Objective】 The current study was conducted to clarify the effect of the field configuration of ′increasing the number of seedlings per hill with reduced number of hills′ (ISRH) on the canopy structure and light energy distribution characteristics of indica hybrid rice in the southwest China,and provide theoretical and practical basis for the popularization and application of ISRH field configuration in southwest rice area. 【Method】 A single-factor randomized field experiment was conducted to study the effects of different field configurations on canopy structure,light energy distribution,and photosynthetic characteristics of rice at Wenjiang and Hanyuan in Sichuan Province. Two field configurations including the traditional high-density planting (THDP,row hole spacing 30.0 cm × 12.0 cm,1.5 seedlings per hill,single and double seedlings staggered transplanting) and increasing the number of seedlings per hill with reduced number of hills (ISRH,row hole spacing 30.0 cm × 24.0 cm,3 seedlings per hill) were set. 【Result】 ①Compared with THDP,ISRH significantly increased the number of tillers per hill and decreased the leaf inclination angle of the upper three leaves by 0.93 %-3.97 % at heading stage at both study sites,which significantly increased the leaf area and canopy amplitude of single hill by 80.39 % and 28.99%,respectively. ②ISRH improved the permeability of the middle and lower parts of the rice canopy,which contributed to 18.08%-42.55% and 5.49%-44.22% increase in light transmittance of the canopy from 3 cm to 40 cm at Wenjiang and from 3 cm to 100 cm at Hanyuan,respectively. This leaded to the 46.74% and 11.54%-75.63% significant increase the daily radiation and illumination at the bottom of the canopy after heding,respectively. ③Compared with THDP,ISRH effectively improved the photosynthetic capacity of the upper three leaves of rice. The net photosynthetic rates of flag leaf,second leaf and third leaf increased by 16.96%-30.33%,9.35%-16.62% and 12.93%-32.76%,respectively. 【Conclusion】 ISRH improved the canopy structure of Yixiangyou 2115,thereby enhancing the light transmittance and light energy supply at the middle and lower parts of the canopy,which contributed to greater net photosynthetic rate of the upper three leaves of rice.
    The Expression Profiling of bZIP Genes under Adverse Stress in Maize
    JIA Liqiang, LIU Yang, DING Bo, ZHANG Yunlin, ZHAO Qiufang, CHEN Shu
    2023, 41(2):  275-281.  doi:10.16036/j.issn.1000-2650.202105018
    Abstract ( 605 )   PDF (5186KB) ( 132 )   Save
    References | Related Articles | Metrics
    【Objective】 Basic leucine zipper (bZIP) proteins constitute a large family of transcription factors among plants,which play vital roles during plant development. the expression of 11 ZmbZIPs in different tissues or under various stresses in elite maize inbred line Zheng58 could provide reference for the functional study of ZmbZIP or for the resistance breeding. 【Method】 Using qRT-PCR technique, this paper detected the expression profiling of 11 ZmbZIPs of maize inbred line Zheng58 was detected under 200 mmol/L NaCl,20% PEG6000,4 ℃ low temperature and nitrogen dificiency stresses. 【Result】 Plylogenetic tree revealed that 11 ZmbZIPs can be subdivided into 3 subgroups,indicating their genetic relationships. RT-qPCR analysis showed that 11 ZmbZIPs exhibited different expression patterns in different tissues,indicating diverse roles during maize growth and development. Under simulated stress treatment,200 mmol/L NaCl,20% PEG6000,4 ℃ and nitrogen deficiency, the expression patterns of 11 ZmbZIPs were detected,and the results showed that 11 ZmbZIPs were regulated by 4 stress treatments,indicating it′s widely involved in stress signaling pathways. 【Conclusion】 The expression patterns of 11 ZmbZIPs differed in different tissues or in responsive to various stresses. The study can offer valuable information for further revealing its biological functions.
    Study on Physical Characteristics and Seed Vigor of Zhenghong 431 Hybrid-Seeds with Different Maturity
    HE Zhen, YU Xuejie, QUBI Wuhe, LI Renfei, LIU Haohao, KE Yongpei, SHI Haichun
    2023, 41(2):  282-286.  doi:10.16036/j.issn.1000-2650.202112136
    Abstract ( 551 )   PDF (1365KB) ( 83 )   Save
    References | Related Articles | Metrics
    【Objective】 The physical characteristics and seed vigor of hybrids are important to measure the quality of hybrids. The study on the physical characteristics and seed vigor changes of hybrids with different maturity is helpful to guide the production of high quality hybrids. 【Method】 The changes of four physical characteristics (grain length,grain width,100 grain weight and proportion) and vigor of Zhenghong 431 seeds with different maturity were studied in Chengdu,Sichuan (20-55 days after pollination) and Xichang,Sichuan (20-75 days after pollination). 【Result】 The grain length,grain width,100 grain weight and proportion of Zhenghong 431 increased gradually with the maturity,and finally became stable. Among them,the physical characteristics of Zhenghong 431 seeds in Chengdu tended to be stable at the 45th day after pollination,while at the 55th day in Xichang. Through the standard germination test and accelerated aging test,we found that the seed vigor of Zhenghong 431 in Chengdu reached the peak at the 45th day after pollination,while at the 60th day Xichang. 【Conclusion】 When maize hybrid-seeds were produced in Xichang and Chengdu bases of Sichuan province, the harvest was better at 60 and 45 days after pollination,respectively. The seed quality of Zhenghong 431 in Xichang was better than that in Chengdu.
    Identification and Expression Analysis of Drought Stress-Related VrERF Gene Family in Mung Bean
    LI Mengxin, DING Donghui, ZHANG Yupeng, JING Linchao, LU Jianrong, LIU Jiafei, CHEN Jibao, YANG Shuqiong
    2023, 41(2):  287-294.  doi:10.16036/j.issn.1000-2650.202211170
    Abstract ( 417 )   PDF (37919KB) ( 68 )   Save
    References | Related Articles | Metrics
    【Objective】 In order to explore the response mechanism of AP2/ERF transcription factor in mung bean under drought stress. 【Method】 The interspecies homology,interacting protein function and cis-acting elements of VrERF family genes in mung bean were analyzed based on the whole genome sequencing data. The tissue-specific expression of each VrERF gene and the difference of gene expression under drought stress were analyzed by transcriptome sequencing data and verified by qRT-PCR. 【Result】 The ERF family gene of mung bean had that same evolutionary origin as those of pea,kidney bean and soybean,and also had obvious gene expansion. The promoter region of VrERF gene has many cis-acting elements related to hormone response,stress response and growth. In addition,there are extensive interactions among different VrERF proteins in mung bean,which may participate in the defense response of mung bean to abiotic stress through interaction with bZIP,RAP2.4 and STZ. Gene expression analysis shows that the expression of most VrERF family genes has strong tissue specificity,and VrERF7/62 is significantly down-regulated in mung bean VC1973A and JP226873 leaves under drought stress. qRT-PCR analysis also showed that the expression of VrERF7/62 was significantly down-regulated by drought stress. 【Conclusion】 This study speculated that VrERF7/62 might play a negative role in the response to drought stress in mung bean,and laid a foundation for the study of the expression and gene function of AP2/ERF family genes in mung bean.
    Genome‑Wide Identification and Analysis of the Heat Shock Transcription Factor Family in Brassica juncea L.
    YANG Wei, TANG Bing, TAN Guofei, FU Wenyuan, WANG Qingqing, ZENG Qinghong, WANG Hongliang, MA Jianyun, ZHANG Rui, SHI Shaobin, DENG Ying
    2023, 41(2):  295-306.  doi:10.16036/j.issn.1000-2650.202208163
    Abstract ( 529 )   PDF (48187KB) ( 113 )   Save
    References | Related Articles | Metrics
    【Objective】 This paper aims to identify and analyze the members of Hsf transcription factor family in Brassica juncea L. genome,hoping to provide a theoretical basis for the functional research of Brassica juncea L. Hsf gene and genetic improvement to improve stress resistance. 【Method】 Bioinformatics methods were used to analyze the functional structure,conserved motifs,promoter cis acting elements,phylogeny,collinearity of BjuHsf family members,and RNA-seq was also used to verify the gene expression of BjuHsf under low temperature stress. 【Result】 Seventy-one members of the Hsf gene family were identified in the Brassica juncea L. genome,distributed on eighteen chromosomes and grouped into three subfamilies. all BjuHsf proteins contain DBD and HR-A/B domains. The BjuHsf promoter region contains cis-acting elements related to stress,hormones,and growth and development. The phylogenetic and collinearity analysis indicated that the Hsf family members of Brassica juncea L. were more closely related to those of chinese cabbage. Under low temperature stress,BjuHsf gene expression analysis showed that eight BjuHsf genes were significantly up-regulated. 【Conclusion】 These differentially expressed BjuHsf genes are related to cold tolerance of Brassica juncea L. and can be used as candidate genes for genetic improvement of cold tolerance of Brassica juncea L.
    Study on Physiological Effects of 1-MCP Treatment of Postharvest ′Hongyang′ Kiwifruit
    LIN Jinyu, XIAO Li, YANG Chunping, GONG Guoshu, CHEN Huabao
    2023, 41(2):  307-317.  doi:10.16036/j.issn.1000-2650.202210184
    Abstract ( 468 )   PDF (7228KB) ( 72 )   Save
    References | Related Articles | Metrics
    【Objective】 This study purposes to investigate the molecular regulation mechanism of preservation under the conditions of 1-MCP treatment combined with refrigeration (1-4 ℃) storage of post-harvest ′Hong yang′ kiwifruit. 【Method】 In this experiment,the fruits were used as the material,and 1-MCP and refrigeration were used to observe the change in the physiological effects of fruits during storage. 【Result】 The results showed that 1-MCP treatment combined with cold storage slowed down the decrease of kiwi fruit hardness,inhibited the degradation of TSS,titratable acid,VC and anthocyanin,slowed down the accumulation of MDA,maintained the vitality of SOD,and reduced the ethylene release to delay the arrival of the peak of ethylene release. By performing comparative transcriptomic analysis using RNA-seq technology,a total of 2 380 differentially expressed genes were screened,including 1 503 upregulated and 877 downregulated expressed genes. The GO enrichment analysis indicated that the differentially expressed genes were significantly enriched in the functional categories of cellular components,molecular function,and biological processes,including peptide biosynthesis and metabolism,amide biosynthesis,protein transport,and defense response. KEGG enrichment analysis showed that the upregulated genes were mainly enriched in the plant hormone signaling transduction pathway,cysteine and methionine metabolism pathways,and antioxidant-related pathways such as phenylalanine metabolism and glutathione metabolism. It is speculated that the increased expression of methionine metabolism is one of the main reasons for reducing ethylene synthesis. The downregulation was mainly enriched in pyruvate metabolism pathways,chlorophyll metabolism,nicotinic niacin and nicotinamide metabolism,and proteasome metabolism pathway and other pathways that affect the intensity of respiration. 【Conclusion】 1-MCP combined with cold treatment of ′Hong yang′ kiwifruit,through improving the fruit antioxidant-related gene expression,reduce the ethylene synthesis precursor and inhibiting the respiration-related gene expression,so as to achieve the preservation effect of delaying the fruit aging. This study revealed the preservation mechanism of 1-MCP from the molecular level and provided a theoretical reference for the preservation research of ′Hong yang′ kiwifruit.
    Effects of Different Fertilization on Rhizosphere Microbial Biomass, Soil Enzyme Activity and Physiology of Grape Seedlings
    LIU Fang, WANG Hangfei, PU Chunyan, CAI Ziyang, WU Sanlin
    2023, 41(2):  318-324.  doi:10.16036/j.issn.1000-2650.202209157
    Abstract ( 509 )   PDF (1437KB) ( 135 )   Save
    References | Related Articles | Metrics
    【Objective】 This study aims to investigate the effects of different fertilization treatments on microbial mass, soil enzyme activity and physiology of grapes in the rhizosphere. 【Method】 The grape seedlings of three varieties of Nina Queen, Summer Black and Shine Muscat have been selected as test materials, each of which has been adopted with three fertilization methods respectively:application of well-rotted organic fertilizer (CK group), rotten organic fertilizer+microbial fertilizer (compound microbial fertilizer group) and rotted organic fertilizer+bamboo fiber microbial fertilizer (bamboo fiber fertilizer group). Rhizosphere soil has been randomly collected to determine soil nitrogen, phosphorus and potassium content, microbial biomass and soil enzyme activity, and chlorophyll content and relative leaf water content of grape seedlings. 【Result】 Both bacterial fertilizers can significantly increase the contents of available nitrogen, available phosphorus and available potassium in the rhizosphere soil of the three varieties of grapes, and the bamboo fiber fertilizer group was significantly higher than that in the compound microbial fertilizer group. Both kinds of bacterial fertilizers can significantly increase the microbial biomass of grape rhizosphere, and the number of bacteria in the bamboo fiber fertilizer group was significantly higher than that in the compound microbial fertilizer group, while there was no significant difference between fungi and actinomycetes. The activities of urease, sucrase and phosphatase in soil under bamboo fiber fertilizer were greatly increased, and the compound microbial fertilizer group had an increase, but the increase was relatively small, and the effect of the two bacterial fertilizers on soil catalase activity was small, but there was still a slight increase, and the bamboo fiber fertilizer was higher than that of the compound microbial fertilizer. Both bacterial fertilizers can significantly increase the chlorophyll content and relative water content of grape leaves, and the bamboo fiber fertilizer group was slightly higher than that of the compound microbial fertilizer group. 【Conclusion】 The application of bamboo fiber fertilizer can effectively solve the problem of adaptability of plant rhizosphere microorganisms in soil, and significantly increase the microbial biomass of grape rhizosphere soil. It increases the activity of urease, catalase, sucrase and phosphatase in rhizosphere soil, promotes the transformation of nutrients in soil matrix, increases the content of soil nutrients in nitrogen, phosphorus and potassium, and increases the chlorophyll content and relative water content of grape seedlings.
    Predicting the Current and Future Potential Distribution of the Fall Armyworm, Spodoptera frugiperda (J. E. Smith), under Changing Climate in Sichuan Province, China
    ZHANG Xueyan, XIE Wenqi, FENG Chuanhong, MA Li, LI Qing, YANG Qunfang, WANG Rulin, JIANG Chunxian
    2023, 41(2):  325-334.  doi:10.16036/j.issn.1000-2650.202205151
    Abstract ( 487 )   PDF (8540KB) ( 60 )   Save
    References | Related Articles | Metrics
    【Objective】 This paper aims to clarify the potential distribution of Spodoptera frugiperda in Sichuan Province and provide reference for monitoring, early warning and prevention S. frugiperda in Sichuan. 【Method】 This study first optimized the parameters of the MaxEnt model. Then, the optimized MaxEnt model and the latest version of WorldClim were used to predict the potential distribution of S. frugiperda in Sichuan under different climate backgrounds at present and in the future. 【Result】 The potential distribution area of S. frugiperda in Sichuan is 25.166 4 million hm2, accounting for 51.18% of the total area of Sichuan. Most areas in Sichuan are potential distribution areas for S. frugiperda, except for the Tibetan Autonomous Prefecture of Garzê and Tibetan Qiang Autonomous Prefecture of Ngawa on the Western Sichuan Plateau and parts of Liangshan Yi Autonomous Prefecture in southwestern Sichuan. Based on the overall distribution trend, the suitability increases from west to east. Under future climate change scenarios, the range of the potential distribution area for S. frugiperda will expand. The area of high suitability will increase by 9.00%~37.67% of the current area; the areas of medium and low suitability will decrease by 13.29%~52.21% and 3.44%~26.08%, respectively; and the unsuitable area will decrease by 1.60%~16.72%. 【Conclusion】 Sichuan Province has a large area of potential distribution for S. frugiperda. Under the future climate conditions, the potential distribution of S. frugiperda in Sichuan will expand westward and northward.
    Animal Science
    Effects of ACACA Gene Interference on Proliferation and Adipogenic Transdifferentiation of Porcine Muscle Satellite Cells
    LEI Yuhang, TAN Ya, HUANG Zhiyang, ZHAO Mengying, QI Jing, GAN Mailin, SHEN Linyuan, ZHU Li
    2023, 41(2):  335-343.  doi:10.16036/j.issn.1000-2650.202209180
    Abstract ( 78 )   PDF (19292KB) ( 90 )   Save
    References | Related Articles | Metrics
    【Objective】 The purpose of this study was to investigate the effects of acetyl-CoA carboxylase α (ACACA)on proliferation, apoptosis and transdifferentiation of porcine muscle satellite cells(MSCs). 【Method】 MSCs were cultured in vitro in this study to mimic the formation of porcine intramuscular fat. The ACACA gene sequence was used to design three small interfering RNAs, and the siRNA with the greatest amount of interference was chosen for transfection using quantitative real-time PCR (qRT-PCR). The proliferation, apoptosis, and formation of lipid droplets of MSCs were assessed by qRT-PCR, CCK-8 cell proliferation assay, flow cytometry, oil Red O staining, and triglyceride (TG) detection techniques after successfully inhibiting the expression of ACACA in MSCs. 【Result】 The results showed that after ACACA interference in the proliferation phase, the expression levels of the cell cycle marker gene Cyclin D1P<0.05), Cyclin EP<0.000 1), and the anti-apoptotic gene Bcl-2P<0.05)were down-regulated, while the expression level of the pro-apoptotic gene BAXP<0.05)was up-regulated in MSCs. MSCs had the capacity to transdifferentiate into adipocytes following the induction of adipogenic transdifferentiation, and ACACA interference significantly decreased the number of lipid droplets in MSCs(P<0.000 1). 【Conclusion】 The presented results indicated that the MSCs' proliferation and apoptosis were inhibited by the ACACA gene interference, which also prevented the formation of lipid droplets during adipogenic transdifferentiation. The findings provided experimental guidelines and fundamental information for further research on the impact of ACACA on intramuscular fat and the control mechanism of pork products.
    Cloning Sequencing of PRLR Gene and Differential Expression Analysis of Different Tissues
    LI Xiaojun, SUI Zhiyuan, WANG Chenguang, ZHANG Yongjie, ZHANG Zhishuai, XING Feng
    2023, 41(2):  344-351.  doi:10.16036/j.issn.1000-2650.202210176
    Abstract ( 468 )   PDF (6032KB) ( 129 )   Save
    References | Related Articles | Metrics
    【Objective】 This study was conducted to clone the CDS sequence of prolactin receptor gene (PRLR) of Duolang sheep and detect the expression difference of PRLR gene before and after the initial estrus in different tissues, so as to provide reference for the main role of PRLR gene in the initiation of the initial estrus. 【Method】 RT-PCR technology and relevant biological information software were used to predict the structure and function of the encoded protein, and qPCR was used to detect the expression level of PRLR gene in each tissue of Duolang sheep before and after the first estrus stage. 【Result】 The CDs sequence of PRLR gene of Duolang sheep was 1 746 bp in length. PRLR gene was expressed in all five tissues of Duolang sheep at three stages. The expression level of PRLR gene in pituitary tissues of Duolang sheep before estrus was significantly higher than that in other tissues (P<0.05). The expression level of PRLR gene in pituitary tissues was still significantly higher than that in the other four tissues (P<0.05), and the expression level of PRLR gene in hypothalamus and pituitary tissues was significantly higher than that in the other three tissues after the initial estrus (P<0.05). The expression of PRLR gene was increased in pituitary and oviduct tissues during the initial estrus period, and was significantly higher after the initial estrus period than before and after the initial estrus period (P<0.05). 【Conclusion】 These results suggest that PRLR gene may be involved in the regulation of estrus initiation in Duolang sheep.
    Effects of Dietary Probiotics on Testis Development and Antioxidant Function of Green Shell Laying Hens
    LI Dan, JIANG Yuru, ZHANG Zhipeng, DU Wei, XU Hengyong, ZHANG Yao, ZHU Qing, WANG Yan
    2023, 41(2):  352-359.  doi:10.16036/j.issn.1000-2650.202207177
    Abstract ( 319 )   PDF (13814KB) ( 92 )   Save
    References | Related Articles | Metrics
    【Objective】 This experiment was conducted to investigate the effects of dietary probiotics (The main components are Bacillus subtilis, Lactic Acid Bacteria and Saccharomyces) on testicular development, hormone levels of blood and testicular antioxidant capacity of green shell laying hens. 【Method】 90 healthy green shell laying hens at 30 days of age with similar body weight were randomly divided into 2 groups with 3 replicates per group and 15 hens per replicate. The control group was fed a basal diet, and the experimental group was fed a basal diet supplemented with compound probiotics in the proportion of 1/1 000. The feeding period was 40 weeks. At the peak of sexual maturity (240 days old age), the relative semen quality, testicular development, the contents of main reproductive hormones in serum and the activity of antioxidant enzymes in serum were evaluated. 【Result】 ①Compared with the control group, the sperm motility, sperm motility rate, deformity rate and pH value of the experimental group were increased by 5.6%, 9.5%, 21.4% and 1.5% respectively, but there was no significant difference between the two groups (P>0.05), meanwhile, the amount of spermatogenic tubule in testis was higher than that in control group; ②compared with the control group, the serum levels of testosterone (T), estradiol (E2), glutathione peroxidase (GSH-Px) and superoxide dismutase (T-SOD) in experimental groups were very significantly increased (P<0.01), the total antioxidant capacity (T-AOC) level was significantly increased (P<0.05), while luteinizing hormone (LH) increased slightly, but the difference was not significant (P>0.05). ③Compared with the control group, the expression levels of Caspase-3 and Caspase-9 in testes of experimental group were decreased, but the difference was not significant (P>0.05), while the expression levels of proliferation and CyclinD1 related genes PCNA, CDK2 and CyclinD1 were increased. In addition, the expression levels of antioxidant genes GPX2, GPX3, GPX4, GPX7, GST and GSR in experimental group were significantly higher than those in control group (P<0.01, P<0.05). 【Conclusion】 The supplementation of probiotics in the diet of green shell laying hens can improve the spermquality, enhance the antioxidant capacity of testis, and improve the reproductive capacity of breeding cocks to some extent.
    Effects of Different Temperature and Salinity on Oxygen Consumption Rate and Ammonia-N Excretion Rate of Paphia textile
    LU Lili, YU Dahui, QIN Suijie, CHEN Jian, ZHAO Sen, BAI Lirong
    2023, 41(2):  360-364.  doi:10.16036/j.issn.1000-2650.202205158
    Abstract ( 527 )   PDF (1337KB) ( 106 )   Save
    References | Related Articles | Metrics
    【Objective】 This paper aims to explore the effects of different temperature and salinity on RO(on oxygen consumption rate) and RN(ammonia excretion rate) of Paphia textile. It provides a basis for the breeding of this shellfish. 【Method】 The effects of temperature (10,15,20,25,30) and salinity (15,20,25,30 ℃) on RO and RN of P. textile were studied by experimental ecological method. 【Result】 At the temperature of 10-30 ℃, with the increase of water temperature, the RO of P. textile gradually increased, while the RN first increased and then decreased, reaching the maximum at 20 ℃; When the salinity is 15-30, with the increase of salinity, the RO and RN of P. textile gradually increase. When the salinity is 25, the RN decreases slightly. In the range of salinity 29 and water temperature 10-30 ℃, the O∶N value of P. textile is 16.320-71.046, with an average value of 31.692. When the water temperature is 24 ℃ and the salinity is 15-30, the O∶N value is 10.459-32.974, and the average value is 19.060. Under the experimental conditions, according to the experimental data, we got equation between RO and temperature: y=0.027 7x+0.130 1, R²=0.985 2; between RN and temperature: y=-0.000 2x2+0.007 8x-0.045 4, =0.808 4; RO and salinity: y=0.047 2x-0.637 4, R²=0.922; between RN and salinity: y=-0.000 2x2+0.010 2x-0.117 9, =0.767 3; O∶N and temperature: y=0.296 5x2-9.898x+96.218, =0.874 1; O∶N and salinity: y=0.233 4x2-11.581x+154.21, R²=1. 【Conclusion】 The optimum temperature and salinity for the survival of P. textile are 25 ℃ and 25, respectively. The results provide a reference for its artificial breeding and large-scale breeding management.
    New Insights into the Differential Effects of Immunocastration Versus Surgical Castration on Skeletal Muscle Accumulation in Male Sprague-Dawley Rats
    LI Zhenhong, LI Haoqing, LI Jiaxin, ZENG Xianyin, HAN Xingfa
    2023, 41(2):  365-371.  doi:10.16036/j.issn.1000-2650.202206155
    Abstract ( 432 )   PDF (14307KB) ( 81 )   Save
    References | Related Articles | Metrics
    【Objective】 This study was aimed to explore the differential effects of immunocastration versus surgical castration on skeletal muscle accumulation as well as its underlying mechanisms using the male SD rat as model. 【Method】 The gastrocnemius muscle mass, histology as well as its accumulation-associated hormone and gene expression level were analyzed comparatively between immunocastrated and surgically castrated male rats. 【Result】 Compared to immunocastration, surgical castration caused lower serum IGF1 and higher corticosterone levels, higher gastrocnemius myostatin (Mstn) mRNA expression and higher serum urea nitrogen levels in male rats. 【Conclusion】 Lower IGF1 and higher glucocorticoid levels were the important reasons to cause more skeletal muscle myolysis in surgically castrated males than that in immunocastrated males.
    Agricultural Economy
    Farm Size, Land Transfer and Fertilizer Reduction and Efficiency: Based on a Survey Data of 4 745 Rural Households in China
    ZHU Wei, WANG Ruimei
    2023, 41(2):  372-379.  doi:10.16036/j.issn.1000-2650.202211195
    Abstract ( 1154 )   PDF (1339KB) ( 114 )   Save
    References | Related Articles | Metrics
    【Objective】 This paper aims to investigate the relationship between farm size, land transfer and fertilizer reduction and efficiency. 【Method】 Based on the survey data of 4 745 rural households in China in 2017, the effects of farm size and land transfer on the fertilizer use intensity(FUI) and fertilizer use efficiency(FUE) were empirically tested using ordinary least squares and instrumental variable regression methods. 【Result】 The farm size has a significant negative impact on the FUI and a significant positive impact on the FUE. On average, every doubling of the farm size will reduce the FUI by 30% and increase the FUE by 14%. Land transfer has a significant positive effect on the FUI and no significant effect on the FUE. The FUI of farmers who have transferred into land is 14% higher than that of farmers who have not transferred into land. 【Conclusion】 Realizing moderate-scale operation by promoting land transfer can effectively promote fertilizer reduction and efficiency. Further guaranteeing the standardization of land transfer and the stability of land management rights will help to promote farmers who have transferred into land to reduce the FUI.
    Digital Economy, Technological Innovation and Urban-Rural Income Gap in the Context of Common Prosperity——A Quasi-Natural Experiment Based on the "Broadband China" Strategy
    GUO Genlong, CHAI Jia
    2023, 41(2):  380-388.  doi:10.16036/j.issn.1000-2650.202212196
    Abstract ( 1032 )   PDF (2035KB) ( 140 )   Save
    References | Related Articles | Metrics
    【Objective】 The theoretical research on connected topics of the urban-rural income gap can be enriched by the study of the effects of the digital economy, and it can also offer recommendations for reducing the urban-rural income gap. 【Method】 Using data from Chinese cities from 2010 to 2019, this paper conducts an empirical analysis of the mechanism of the effect of the growth of the digital economy on the income gap between urban and rural areas. It views the "Broadband China" plan as a sort of organic experiment in the growth of the digital economy. 【Result】 The income gap between urban and rural areas can be greatly reduced as the digital economy grows. It was concluded as a consequence, and even following the PSM-DID and placebo tests, that the expansion of the digital economy could significantly reduce the income gap between urban and rural regions. Through the analysis of regional heterogeneity, it is concluded that when there are differences in geographical location and degree of marketization, the impact of the digital economy on the urban-rural income gap is also different. The heterogeneity results show that the development of the digital economy has significantly reduced the urban-rural income gap in the central and western regions, and the reduction effect in the western region is greater than that in the central region, but not significant in the eastern region; Moreover, in areas with a high degree of marketization, the effect of reducing the income gap between urban and rural areas is more obvious. The mechanism test results show that the digital economy reduces the urban-rural income gap through technological innovation and digitization. 【Conclusion】 Based on the above analysis, we should continue to carry out the strategy of "Broadband China", play the leading role of demonstration cities, further narrow the urban-rural income gap, and achieve common prosperity.