Current issue

• 2022 Vol.38 No.23 Published:15 August 2022

  Suitable Planting Density of New Maize Variety ‘Yudan 132’ for Mechanical Harvesting LI Keke, DONG Yongbin, WANG Lishuang, WANG Han, LI Yayong, ZHANG Long, LI Yuling 2022, 38 (23):  1-5.  DOI: 10.11924/j.issn.1000-6850.casb2021-1126 Abstract + ( 973 )   HTML ( 3 )   PDF ( 1245KB )   ( 86 ) In order to screen suitable planting density of new maize variety ‘Yudan 132’ for mechanical harvesting, five planting densities, including 60000, 64500, 67500, 72000 and 75000 plants per hectare, were set in Changge and Yuanyang experimental bases, to study the effects of different planting densities on yield and agronomic traits. The results showed that with the increase of planting density, the plant height and ear height of ‘Yudan 132’ gradually increased, while the stalk diameter decreased. The ear tip-barrenness length increased with the increase of planting density, while ear length, ear diameter, kernel row number and kernel number per row showed a downward trend. With the increase of planting density, grain yield increased first and then decreased, and reached the maximum at 67500plants/hm2, showing an approximately parabolic distribution. Therefore, the suitable planting density of new maize variety ‘Yudan 132’ is 67500plants/hm2. This study will provide reference for the promotion and application of ‘Yudan 132’.

  Effects of Different Straw Chemical Mixed Fertilizer Treatments on Growth Characteristics and Yield of Sweet Corn ‘Zhetian 19’ HOU Junfeng, CHEN Bin, BAO Fei, TAN Heping, HAN Hailiang, WANG Guiyue, ZHAO Fucheng 2022, 38 (23):  6-14.  DOI: 10.11924/j.issn.1000-6850.casb2021-0958 Abstract + ( 278 )   HTML ( 2 )   PDF ( 1465KB )   ( 70 ) Straw returning can increase the incidence of diseases and pests, and the slow release of straw nutrients will affect crop growth. The new type of organic-inorganic granular compound fertilizer made of processed straw can not only meet the nutrient demand of crop growth in this season, reduce the application amount and times of fertilizers, but also increase soil organic matter and have a broad application prospect in crop production. This experiment studied the effects of different straw chemical mixed fertilizer treatments on the growth characteristics and yield of sweet corn ‘Zhetian 19’, and clarified the application rates and mode of straw chemical mixed fertilizer in fresh corn planting. Two tests were carried out at Dongyang Corn Research Institute testing base in spring and autumn in 2020. According to different fertilization amounts and methods, 5 straw chemical mixed fertilizer treatments and 2 controls were set up in spring, rod fertilizer treatment was added in autumn. The results showed that there was no significant difference in chlorophyll content between basal application of 150 kg straw chemical mixed granular fertilizer and 20 kg urea in spring and autumn and the control, and the leaf area under the granular fertilizer was higher than that under rod fertilizer. The yield of basal application of 150 kg straw chemical mixed fertilizer and 20 kg urea had no significant difference with that of the control, with only 3.8% decrease. The nitrogen recovery efficiency and dry matter weight of the above basal application mode were higher than those of other treatments, which were 6.39 g/g and 7.82% higher than those of control, indicating that this fertilization mode was more suitable for the nutrient demand of sweet corn. In conclusion, straw chemical mixed granular fertilizer can partly replace chemical fertilizer. Due to the slow-release effect of straw chemical mixed fertilizer, its combined application with urea can meet the nutrient demand of ‘Zhetian 19’ in the whole growth period, and the effect of granular fertilizer is better than that of rod fertilizer. Therefore, 150 kg straw chemical mixed fertilizer and 20 kg urea used for basal application can replace the traditional fertilization mode, and reduce the chemical fertilizer application amount and times. At the same time, this mode can cut the manpower input and raise the production efficiency.

  Application of Plant Carbon Isotope Fractionation in the Study of Water Use Efficiency SHI Ruilin, ZHANG Qingfen, LI Ming, LI Quanqi, ZHANG Mingming 2022, 38 (23):  15-20.  DOI: 10.11924/j.issn.1000-6850.casb2021-0719 Abstract + ( 311 )   HTML ( 2 )   PDF ( 1268KB )   ( 872 ) Stable carbon isotope measurement is not limited by time and space, and the measurement process is simple and accurate. In order to eliminate the defects of conventional methods for measuring water use efficiency (WUE), stable carbon isotope tracing technology can be used in the WUE of indicator crops. The basic principle of stable carbon isotope fractionation was reviewed in this paper. The relationship between the stable carbon isotope fractionation characteristics and WUE, and the application of stable carbon isotope fractionation in drought resistance and water saving breeding were analyzed from plant organs, climate factors and water conditions. The stable carbon isotope fractionation characteristics of different photosynthetic plants show that WUE is correlated with carbon isotope ratio (δ13C) and carbon isotope resolution (Δ13C), and the δ13C values of different plant organs are different. Rainfall, light intensity and duration, and soil moisture have significant effects on the δ13C values and WUE. Therefore, δ13C and Δ13C, the two stable carbon isotope indexes can indicate the high WUE and drought resistance of plants better, and provide a theoretical basis for improving plant WUE and breeding drought-resistant varieties.

  Molecular Identity for Sugar Beet Varieties: Establishment Based on DAMD Molecular Marker ZHANG Ziruo, MA Jiajie, GAO Qiuyu, WU Zedong 2022, 38 (23):  21-26.  DOI: 10.11924/j.issn.1000-6850.casb2022-0186 Abstract + ( 280 )   HTML ( 1 )   PDF ( 1518KB )   ( 194 ) In order to quickly distinguish and identify the authenticity and specificity of sugar beet varieties according to their genetic backgrounds, and to replenish the shortcoming and break the limitation of morphological identification, using 96 registered sugar beet varieties as test materials, the molecular identity of varieties was constructed by DAMD molecular marker technology. The results showed that 7 DAMD primers with clear amplification bands and good polymorphism could be used to identify sugar beet varieties. A total of 103 bands were detected, including 101 polymorphic bands, and the polymorphism was 98.1%. The minimum genetic distance among the 96 varieties was 0.039, the maximum was 0.485, and the average genetic distance was 0.237. Through cluster analysis, the 96 sugar beet varieties were divided into two groups, group I only had variety number 54, group II contained the rest 95 varieties, and group II was further divided into two subgroups. After that, the 96 sugar beet varieties were completely distinguished by the combination of three primers URP1F, URP17R and URP2R. The establishment of molecular identity of sugar beet varieties based on DAMD primers provided a new way for rapid and efficient identification of sugar beet varieties, and also provided a guarantee for protecting the interests of breeders and farmers.

  The Water Requirement Law of Qingyang Apple Tree YAO Zhilong, HAN Ping, WANG Junfeng, WANG Jiaqian 2022, 38 (23):  27-31.  DOI: 10.11924/j.issn.1000-6850.casb2021-0847 Abstract + ( 241 )   HTML ( 1 )   PDF ( 1369KB )   ( 74 ) In order to study the water requirement law of apple trees in semi-arid areas, the soil in the closed fruit tree root region was used as test material to prevent ground evaporation, and the soil moisture content was measured regularly and continuously to estimate the transpiration of fruit trees. The results showed that the main vertical space of soil water absorption of 9-year dwarf interstock fruit tree was 0-60 cm soil layer, and the moisture content of soil layer below 60 cm had no obvious change. The transpiration water consumption of fruit trees was 134 kg/tree in autumn and 104 kg/tree from budding to flowering stage in spring. Therefore, in field management, it is more scientific to determine water-saving irrigation in 0-60 cm wet layer.

  Effects of Exogenous Silicon on Photosynthesis and Chlorophyll Fluorescence Characteristics and Antioxidant Enzymes of Cryptocarya concinna Seedlings Under Salt Stress HUANG Pingsheng, LIU Shinan, LI Ting, QIN Yonghua 2022, 38 (23):  32-38.  DOI: 10.11924/j.issn.1000-6850.casb2022-0121 Abstract + ( 243 )   HTML ( 2 )   PDF ( 1394KB )   ( 103 ) In this study,one-year-old seedlings of Cryptocarya concinna were treated with different concentrations (0, 0.5, 1 and 2 mmol/L) of exogenous silicon under salt stress at 100 mg/L NaCl. The chlorophyll content, photosynthesis and chlorophyll fluorescence characteristics and antioxidant enzymes were determined and analyzed for investigating the effects of exogenous silicon on C. concinna exposed to NaCl stress. The results indicated that exogenous silicon could increase the contents of chlorophyll a, chlorophyll b and carotenoid, the activities of SOD, PPO and APX, and the values of Pn, Tr, Gs and Fv/Fm, while reduce the MDA content and Ci value. By comparing different treatments, PPO content was the highest under the treatment of adding 1.0 mmol/L Si and other indexes were the highest under the treatment of adding 2.0 mmol/L Si. In conclusion, the addition of appropriate concentration of exogenous silicon can alleviate the damage of salt stress to C. concinna seedlings and improve seedling salt tolerance. This study will provide reference for the introduction and cultivation of C. concinna.

  Effects of Different Topdressing Measures on the Growth of Current-year Cutting Seedlings of Elaeagnus mooraroftii Abdurishid RAHMAN, Yiliminuer , Talipujiang ABUDOUKEREMU, Haliguli AINI, Ruxianguli YIGANMU 2022, 38 (23):  39-48.  DOI: 10.11924/j.issn.1000-6850.casb2021-0949 Abstract + ( 308 )   HTML ( 1 )   PDF ( 1500KB )   ( 20 ) The purpose of this research is to provide basic materials for promoting the growth of current-year cutting seedlings of Elaeagnus mooraroftii, and lay a foundation for further research on the cutting seedling raising of E. mooraroftii. Using the current-year cutting seedlings of E. mooraroftii as the test materials, 3 sample areas and 12 treatments were set up, and urea, compound fertilizer and control were applied as topdressing, to determine the optimal fertilization amount. Among the 3 sample areas, the highest tree height, the biggest ground diameter, the highest length of the longest and shortest branch, and the biggest base diameter of the longest and shortest branch of E. mooraroftii were all observed in sample area 2, which was 212 cm, 16.26 mm, 99 cm, 33 cm, 6.28 mm, and 3.51 mm, respectively. The average membership function of each growth index in sample area 2 was the maximum of 0.390, while that in sample area 3 was the minimum of 0.189. The order of comprehensive evaluation of the three sample areas was: sample area 2 > sample area 1 > sample area 3. Under the soil condition of sample area 2, 840 kg/hm2 was the optimal fertilizer amount. This study evaluated the optimal fertilizer amount for promoting the growth of cutting seedlings of E. mooraroftii and provided a basis for the cultivation technology research on cutting seedlings of E. mooraroftii.

  The Evaluation of Forest Ecosystem Service Function Value in Guandi Mountain State-owned Forest Region in Shanxi Province WANG Xiaokang 2022, 38 (23):  49-55.  DOI: 10.11924/j.issn.1000-6850.casb2022-0280 Abstract + ( 265 )   HTML ( 1 )   PDF ( 1299KB )   ( 49 ) This study evaluates the value of forest ecosystem service function in Guandi Mountain state-owned forest region, aiming to provide a scientific basis and data support for objectively assessing the ecological benefits of the Natural Forest Protection Project, carrying out forest management and ecological benefit compensation, and realizing the value of ecological products. The study is based on the national forestry industry standard Forest Ecosystem Service Function Evaluation Specification (GB/T 38582—2020), and the second-class survey data of forest resources in 2019. The research shows that the total value of forest ecosystem service function in Guandi Mountain state-owned forest region is 21.442 billion yuan. The functions with the largest value are the value of purifying the environment, the value of water conservation and the value of oxygen release, accounting for 81.62% of the total value. Wenyuhe Forest Farm has the largest value of 1.491 billion yuan, and Wucheng Seed Garden has the smallest value of 0.229 billion yuan. Among the main stand types, arbor forest accounts for 85.46% of the total value, and shrubbery accounts for 14.54%. The value order of the main tree species is: Pinus tabulaeformis > Quercus liaotungensis > Larch> Poplar> Birch > Arborvitae> Spruce. Guandi Mountain state-owned forest region has a high value of forest ecosystem service function and plays an important role in the forest ecosystem service function in Shanxi Province. It is recommended to carry out scientific protection and restoration, improve forest quality accurately and monitor ecological benefit continuously, in order to maximize the value of forest ecosystem service function.

  Effects of Nano-silver Prepared from Tea Extract on Soil Microorganisms HONG Ciqing, SUN Yuyao, MO Wenjing, FANG Yun, CHEN Fangrong, GUI Fangze, GUAN Xiong, PAN Xiaohong 2022, 38 (23):  56-63.  DOI: 10.11924/j.issn.1000-6850.casb2022-0240 Abstract + ( 254 )   HTML ( 3 )   PDF ( 2844KB )   ( 86 ) To explore the effect of nano-silver prepared from tea extract on the biosafety of soil microorganisms, the nano-silver used as antibacterial materials were synthesized by plant reduction method, and prepared into 1000 mg/L nano-silver spray. Then, we analyzed nano-silver’s impact on soil microbial diversity and richness. The results showed that the population of microorganisms was similar in the soil samples of blank control group (CK) and experimental group (Nano-Ag), but the richness of microorganisms was different. In both the experimental group and the blank control group, the Coverage value was high (Coverage>99.71%), the Shannon index was high (Shannon>5.46), and the Simpson index was low (Simpson<0.02), while ACE index and Chao index had little difference between CK and Nano-Ag group (ACE<2, Chao<6). In addition, the nano-silver inhibited the growth of Proteobacteria (Alphaproteobacteria) and Actinobacteria (Thermoleophilia), but promoted the growth of Chloroflexi (Ktedonobacteria). This study verifies that nano-silver has a certain degree of biosafety, which will broaden the potential application scope of nano-sliver and lay a foundation for the further application of nanomaterials in environmental and medical fields.

  Evolution of Soil Trace Elements with Utilization Time in Coastal Plain in Zhejiang Province ZHANG Jian, ZHANG Mingkui, XIE Guoxiong 2022, 38 (23):  64-69.  DOI: 10.11924/j.issn.1000-6850.casb2021-0896 Abstract + ( 291 )   HTML ( 2 )   PDF ( 1187KB )   ( 61 ) To understand the changing characteristics of trace elements in cultivated soils of the coastal plain, soil chronosequence with different reclamation and utilization time was established in northern and southern Zhejiang, and both mixed surface soil samples and soil profile horizon samples with different reclamation and utilization time were collected to analyze the basic properties of the soils and the total and available contents of soil trace elements. The results show that reclamation and utilization time has great influence on the contents of trace elements. With the increase of reclamation and utilization time, the contents of copper and zinc in the soil increase, while the contents of soil iron, manganese, boron and molybdenum decrease. The contents of available copper, zinc, iron and manganese increase significantly, while the contents of available boron and molybdenum decrease significantly. The increase of reclamation and utilization time could also enlarge the difference of the contents of trace elements between upper and lower soil layers. The contents of copper, zinc and molybdenum decrease from top to bottom, while the contents of iron, manganese and boron increase from top to bottom. The effects of reclamation and utilization time on soil trace elements are mainly due to the changes of basic soil properties and the leaching effect of long-term rice planting.

  Soil Physicochemical Characteristics and Comprehensive Fertility of Pinus densiflora Artificial Forests in Shandong Province CHENG Hongyan, ZHANG Lanying, WANG Feng, DU Zhenyu 2022, 38 (23):  70-76.  DOI: 10.11924/j.issn.1000-6850.casb2021-0860 Abstract + ( 296 )   HTML ( 1 )   PDF ( 1412KB )   ( 64 ) Soil physicochemical characteristics are important parts of soil fertility. The research on soil physical and chemical properties and the evaluation of soil fertility are of great significance for the diagnosis of soil quality, which can provide a scientific basis for the rational management of artificial forests. The authors took 35 typical plots of Pinus densiflora forests in the mountainous area of central Shandong Province and the hilly area of eastern Shandong Province as the objects, through the combination of field investigation and indoor analysis, 13 soil indexes were sampled and determined, and the physical and chemical properties of forest soil were studied. The comprehensive index method was used to evaluate the soil fertility of P. densiflora forests. The results showed that the content of soil organic matter, total nitrogen, available nitrogen and available potassium were at the middle level, while the content of available phosphorus was relatively low. The soil pH was acidic, and the soil electrical conductivity (EC) was generally very low, ranging from 19.6 to 115.6 μS/cm, and cation exchange capacity (CEC) was also low as a whole; the soil bulk density and porosity were in the moderate grade, 74.54% and 65.71% respectively. The overall thickness of soil layer was at a moderate level. The average value of soil clay content was only 9.35%, which was at a low or very low level, resulting in a relatively high silt/clay ratio. There were great differences in soil comprehensive fertility among different plots; the comprehensive soil fertility of P. densiflora forests in Kunyu District of Yantai and Yiyuan County of Zibo were the highest, significantly higher than that in other counties. The soil fertility index of P. densiflora forests in the mountainous area of central Shandong was higher than that in the hilly area of eastern Shandong. There was a significantly negative correlation between stand density and soil comprehensive fertility index.

  Effects of Organosilicone Soil Conditioner and Functional Fertilizer on Saline-alkali Soil Improvement and Sunflower Yield LIU Juan, LIANG Junmei, DUAN Yu, YAN Hong, WEN Xiaoliang, WANG Ruizhen, LI Shanrui, LI Erzhen, ZHONG Shengzhu, LI Bing 2022, 38 (23):  77-81.  DOI: 10.11924/j.issn.1000-6850.casb2021-0129 Abstract + ( 271 )   HTML ( 1 )   PDF ( 1239KB )   ( 40 ) To investigate the effects of organosilicone soil conditioner and organosilicone functional base fertilizer on the alkalization degree of saline-alkali soil and the increase of crop yield in Hetao irrigation area, three treatments were set up through field plot experiment in Wuyuan County, Bayannur City, Inner Mongolia: (1) organosilicone soil conditioner 45 kg/hm2 and organosilicone functional fertilizer 7.5 kg/hm2; (2) organosilicone soil conditioner 75 kg/hm2 and organosilicone functional base fertilizer 5 kg/hm2; (3) diammonium phosphate 16.3 kg/hm2, potassium chloride 16.5 kg/hm2, and urea 11.5 kg/hm2. The results showed that the application of organosilicone soil conditioner could increase the 100-grain weight of sunflower, and then increase the yield of sunflower. With the increase of the application amount of organosilicone soil conditioner, the yield of sunflower showed an upward trend. When the application amount of organosilicone soil conditioner was 75 kg/hm2, the yield increase range was 9.0%, and the yield increase effect was significant. Under the premise of 45 kg/hm2 of organosilicone soil conditioner and 7.5 kg/hm2 of organosilicone functional fertilizer, the economic benefit was the best. The application of organosilicone soil conditioner could increase the soil available nutrients, reduce the soil pH, salt content, alkalinity and bulk density, and effectively improve the quality of cultivated land, restore soil condition and reduce the level of obstacles to plant growth.

  Characteristics of Soil Nitrogen Leaching in Facility Vegetable Fields and the Control Measures: A Review XIE Hongbao, GUAN Shiyang, CHEN Yimin, SUI Yueyu, PENG Bo, TANG Boyu, JIAO Xiaoguang 2022, 38 (23):  82-87.  DOI: 10.11924/j.issn.1000-6850.casb2022-0331 Abstract + ( 359 )   HTML ( 3 )   PDF ( 1071KB )   ( 46 ) Facility vegetable fields occupy an important proportion in the production of vegetable crops. As the nutrient element with the highest demand in the production of facility vegetables, soil nitrogen plays an irreplaceable role in ensuring the quality and yield of facility vegetables. However, due to the facts that the soil in the facility vegetable fields has always been in a state of being highly intensive and highly fertilized, and has high land utilization rate, the soil nitrogen utilization rate is low and the leaching loss is serious. Based on the research results of soil nitrogen leaching characteristics in facility vegetable fields from 2001 to 2021 at home and abroad, this paper started with an overview of soil nitrogen loss pathways and leaching characteristics in facility vegetable fields, and analyzed the impact mechanism of soil nitrogen leaching in facility vegetable fields. It is concluded that nitrogen leaching loss in facility vegetable fields is mainly affected by fertilization, irrigation, soil texture and planting years. Measures such as reducing nitrogen and controlling water, adjusting soil carbon and nitrogen ratio, applying soil inhibitors, and using idle crops could ensure crop quality in the facility vegetable fields and reduce the loss of soil nitrogen leaching. This paper discusses the future research direction of nitrogen leaching loss in facility vegetable fields, aiming to provide a theoretical basis for the rational management and ecological recycling of facility vegetable fields.

  Evaluation Indexes of Guide Soft Pear: An Agricultural Product with Good Climate Indicators ZHONG Cun, WEI Peng, ZHANG Haijing 2022, 38 (23):  88-94.  DOI: 10.11924/j.issn.1000-6850.casb2021-0791 Abstract + ( 279 )   HTML ( 3 )   PDF ( 2065KB )   ( 164 ) To improve the economic benefits of pear cultivation in Guide of Qinghai Province, this study selected Guide soft pear with Geographical Indication Products Certificate from the local high-quality agricultural products, and carried out the ‘Agricultural Products with Good Climate Indicators’ identification on its agricultural product climate quality, to determine the evaluation indexes of Guide soft pear. Taking the comprehensive authentication method, we analyzed the proportion of the indicators including ecological adaptability affecting the growth of agricultural products, the climate condition of the study year, the level of orchard management and the fruit quality of the study year, and gave different weights to each indicator. Then, we determined the composite score by analyzing and grading the indicators. In addition, we selected the soft pears from Guide County Horticulture Farm in 2020 to evaluate the identification indicators. The results showed that Guide County Horticulture Farm in 2020 had rich light and heat resources, suitable moisture condition, good light, heat and water configuration, and obvious climate advantages, which were conducive to high-quality soft pear production. The climate quality grade of Guide soft pear produced in 2020 was ‘extra excellent’.

  Meteorological Conditions of Dongshan Loquat in 2019 - 2021: Evaluation and Comparative Analysis TAO Zhengda, LI Haoyu, ZHAO Jingxian, WANG Jun 2022, 38 (23):  95-101.  DOI: 10.11924/j.issn.1000-6850.casb2021-1001 Abstract + ( 241 )   HTML ( 4 )   PDF ( 2022KB )   ( 117 ) Dongshan town in Wuzhong District of Suzhou is one of the four traditional loquat production areas in China, and loquat is an important cash crop in Wuzhong District. However, the annual yield of loquat is unstable because its growth and development are easily affected by meteorological conditions. Therefore, using meteorological data to analyze the influence of meteorological conditions on loquat is conducive to the scientific development of loquat industry and the promotion of meteorological services for agriculture. Based on the method of mathematical statistics, this paper analyzed the loquat yield and meteorological conditions from 2019 to 2021 in Wuzhong. The results showed that the overall meteorological conditions were relatively suitable for loquat growth from 2019 to 2021, but disastrous weather also existed at the same time. The main adverse meteorological conditions of loquat in 2019 were abnormally less sunshine at florescence and young fruit stage, excessive precipitation at florescence, and low temperature and the snow. The main adverse meteorological condition in 2020 was more sunshine in fruit expansion stage. In 2021, the main adverse meteorological conditions were low temperature and two cold wave processes at florescence and young fruit stage of loquat. According to loquat growth and yield at the same time, the main cause of blossom blight was continuous rainy days during flowering period, which could be characterized by the abnormally more precipitation and less sunshine. The anomaly percentage of sunshine less than -50% in two periods of ten days could be taken as the threshold value of loquat blossom blight. In addition, the low temperature, rain and snow caused by the cold wave process were the main reasons of the freezing damage on loquat flowers and corky bark on young fruits in 2021.

  Spatiotemporal Evolution of Extremely Dry/Wet Events and Its Correlation with Oscillation Indexes in the Songnen Plain ZHONG Xin, LIU Baixin, DING Wei 2022, 38 (23):  102-110.  DOI: 10.11924/j.issn.1000-6850.casb2021-1012 Abstract + ( 248 )   HTML ( 1 )   PDF ( 3018KB )   ( 618 ) The Songnen Plain is an important commercial grain base and wetland distribution area in China, and the evolution of dry and wet events is closely related to regional food security and ecological safety. Based on the daily meteorological data including temperature, precipitation and wind speed from 36 meteorological stations in and nearby the Songnen Plain, the monthly surface wetness index of each station was calculated by the Penman-Monteith equation, and the frequency of extremely wet and dry events was further calculated after standardization. Then, the trend analysis and Kriging interpolation method were used to explore the spatiotemporal evolution characteristics of extremely dry and wet events, and the squared wavelet coherence spectrum was adopted to detect the potential annual-scale correlation between the extremely dry and wet events and the Oscillation indexes. The results showed that: (1) annual extremely dry events occurred frequently in the Songnen Plain from 1960 to 2020, with an average value of 7.86 times in the past 60 years, while annual extremely wet events were less frequent; the annual extremely dry event frequency showed an obvious decreasing trend and the annual extremely wet event frequency showed an increasing trend, with the climate tendency rate of -0.10 times/10 a and 0.02 times/10 a, respectively; (2) spatially, the frequency of extremely dry events in most areas of the Songnen Plain was not significantly weakening, while the frequency of extremely wet events was low and the trend was obviously increasing in the east and decreasing in the west; (3) the evolution of dry and wet events in the Songnen Plain was closely related to the Oscillation index, the annual frequency of extremely dry events was positively correlated with the Arctic Oscillation index, the Atlantic North American Oscillation index and the North Atlantic Oscillation index; however, the annual frequency of extremely wet events was mainly negatively correlated with them; in addition, the relationship between the extremely dry and wet events and the Southern Oscillation index exhibited obvious differences on interannual and interdecadal scales; (4) the evolution of the frequency of extremely dry and wet events was closely related to the regional socio-economic sector water consumption, which affected regional water security. This study could provide support for water resource planning and management of the agricultural-wetland system in the Songnen Plain to adapt to climate change.

  The Phenological Characteristics of Menyuan Tamarisk and Their Response to Climate Change QI Ruying, NIE Yongxi, ZHONG Cun 2022, 38 (23):  111-115.  DOI: 10.11924/j.issn.1000-6850.casb2022-0306 Abstract + ( 276 )   HTML ( 1 )   PDF ( 1392KB )   ( 202 ) The tamarisk phenological and temperature data from 1988 to 2020 obtained by Menyuan National Basic Meteorological Station were used, and the change characteristics of Menyuan tamarisk and their response to climate change in spring and autumn (bud opening, leaf spreading, flowering, leaf discoloration and defoliation) were studied by correlation analysis. The results showed that: (1) the phenological phase in spring had an earlier trend, the flowering period was earlier obviously, and the phenological phase in autumn presented a delayed trend; (2) the average growing period of Menyuan tamarisk was 168 days, and the growing period showed a significant lengthening trend with the changing rate of 13 d/10 a; (3) from 1988 to 2020, the annual and seasonal average temperature in Menyuan County had an increasing trend, which was consistent with global warming, the climate tendency rate of the annual average temperature change was 0.54℃/10 a, indicating that the annual average temperature increased by about 1.7℃ in 32 years; (4) the tamarisk phenological phase in spring was very sensitive to the change of temperature, getting earlier with the rising of temperature; (5) during 1988 to 2020, the annual average temperature of Menyuan and the phenological phase of tamarisk did not change abruptly. In summary, Menyuan tamarisk was sensitive to climate change. Therefore, the study on the response of Menyuan tamarisk to climate change in Qilian Mountains’ ecological vulnerable areas has certain reference value for ecological environmental monitoring and management.

  Effect of Different Insecticides on Field Control of Cnaphalocrocis medinalis: An Evaluation HU Zhongliang, WANG Jianhe, XU Kui, SU Ying, CHEN Zhiwei, JIANG Yin 2022, 38 (23):  116-120.  DOI: 10.11924/j.issn.1000-6850.casb2021-1081 Abstract + ( 396 )   HTML ( 3 )   PDF ( 1215KB )   ( 128 ) The study aims to delay the resistance of Cnaphalocrocis medinalis to insecticides, and verify the control effect of the new insecticide scheme on Cnaphalocrocis medinalis, thus providing reference for the scientific control. Two treatments were set up: chlorfenapyr·lufenuron 24% SC 750 g/hm2, and chlorfenapyr·lufenuron 24% SC 450 g/hm2+ indoxacarb 150g /L SC 300 g/hm2. Chlorfenapyr·8% 2100 g/hm2 and water (CK) were the control treatments. The field control effect was determined in different fields and on different rice strains. The results showed that each combination treatment had a high control effect on Cnaphalocrocis medinalis. In the Ningbo experiment, the control effect on Cnaphalocrocis medinalis was over 85% three days after the application of chlorfenapyr·lufenuron 24% SC 750 g/hm2 and chlorfenapyr·lufenuron 24% SC 450 g/hm2+ indoxacarb 150g /L SC 300 g/hm2 in early rice or single-cropping rice fields, and the control effect was over 90% after 7 days. After 14 days, the leaf retention rates of the two treatments were both over 90%. In the Wenzhou experiment, the control effect of chlorfenapyr·lufenuron 24% SC 750 g/hm2 and chlorfenapyr·lufenuron 24% SC 450 g/hm2+ indoxacarb 150 g/L SC 300g/hm2 on single-cropping rice was over 85%, which was consistent with that of the Ningbo experiment, and the control effect after 7 days was over 93%, and after 14 days, the leaf retention rates of the two treatments were also over 90%. The control effect and leaf retention rate of each treatment were better than those of CK. The experiment showed that chlorfenapyr·lufenuron 24% SC and indoxacarb 150 g/L SC were high-effective and fast-acting, and had long-lasting control effect on Cnaphalocrocis medinalis.

  Status Quo and Prospect of Research on Botanical Insecticides Against Stored Grain Pests LIU Jingyi, YUAN Ruixue, LIU Chenghan, SUI Yuzhu, CHEN Haipeng, SUN Yanchun 2022, 38 (23):  121-128.  DOI: 10.11924/j.issn.1000-6850.casb2022-0284 Abstract + ( 510 )   HTML ( 6 )   PDF ( 1219KB )   ( 286 ) The status quo and latest progress of research on botanical insecticides against stored grain pests around the world were reviewed, and the industrialization of botanical insecticides in China was analyzed. Botanical insecticides exhibit a very broad application prospect due to its advantages of diversified insecticidal active compounds, complicated mechanisms of insecticidal action, and being environment-friendly. Studies on botanical insecticides against stored grain pests have been carried out extensively abroad, and most of them focus on the identification of active compounds, insecticidal efficacy and the action mechanism. Currently, there are only a few studies on the application of botanical insecticides for controlling stored grain pests in China, and only limited insecticides have been commercialized. Therefore, further explorations are needed. By summarizing the studies at home and abroad, the problems in the application of botanical insecticides for controlling stored grain pests were analyzed, the corresponding suggestions were put forward, and the future development directions were discussed, aiming to provide reference for future research and industrial application of botanical insecticides in China.

  Investigation on the Infection of Sarcocystis ovis in Xining of Qinghai Province MENG Ru, FU Yong, WANG Shunqin, KANG Ming, ZHANG Chengtu, WU Ying, CHEN Yongzhong, XIE Caiying 2022, 38 (23):  129-134.  DOI: 10.11924/j.issn.1000-6850.casb2021-0096 Abstract + ( 247 )   HTML ( 1 )   PDF ( 3711KB )   ( 156 ) In order to find out the infection intensity and type of Sarcocystis ovis in Xining of Qinghai Province, different parts of muscle tissues of slaughtered sheep were randomly collected from markets, supermarkets and vendors in districts and counties under the jurisdiction of Xining. Microscopic examination and staining section observation were conducted for morphological identification. Genomic DNA extracted from myocardial and diaphragm samples of sheep with high worm content was taken for PCR amplification and sequencing analysis of mitochondrial cytochrome C oxidase subunit 1 (Cox1) gene. The results showed that in Xining, the infection rate of Sarcocystis ovis was 82.5%, and the average infection intensity was 7.67. In terms of parasitic sites, the highest infection rate was found in diaphragm (75%), followed by that in myocardium (67.5%), tongue (57.5%), while no infection was found in esophageal muscle. The muscle tissue at the edge of the worm was loose, and the cyst wall of the worm was divided into two layers. The structure of the primary and secondary cyst wall was flat, without protrusion and wrinkle. The 905bp target fragment was amplified by PCR and the sequence was aligned in GenBank. The homology between the target fragment and the published sequence of Sarcocystis tenella was 98%. So it was identified as Sarcocystis tenella. In conclusion, this research preliminarily clarified that the main infection of sheep in Xining of Qinghai Province is Sarcocystis tenella, and the infection rate in Xining is higher than the average level in China. We suggest that the laboratory detection, transportation and slaughter inspection and quarantine of Sarcocystis ovis in Xining of Qinghai Province should be strengthened, to ensure the sanitary quality of mutton products in market and the health and food safety of the public.

  The Development Strategy of Freshwater Pond Aquaculture in China ZHAO Yongfeng, YU Kai, SONG Qianhong, GE Xianping, LIU Ledan, LUO Hong, CHEN Qian, XU Shuchen 2022, 38 (23):  135-142.  DOI: 10.11924/j.issn.1000-6850.casb2021-0884 Abstract + ( 338 )   HTML ( 1 )   PDF ( 1367KB )   ( 142 ) Freshwater pond aquaculture is the main mode of aquaculture in China, its industrial structure optimization and upgrading is of great significance. The study introduced current status and main species of freshwater pond aquaculture in China, expounded the changes of freshwater pond aquaculture in terms of species structure, culture technology and culture methods, and outlined the main modes of freshwater pond aquaculture in China at present. The study also discussed main problems of freshwater pond aquaculture from eight aspects: species, feed, diseases, environment, aquaculture equipment, aquatic product quality and safety, and aquaculture management, and put forward suggestions on each of these problems, in order to provide ideas for the healthy, high-yield, environmental protection and standardized development of modern freshwater pond aquaculture in China.

  Effects of Population Size on the Collective Behavior of Juvenile Bighead Carp ZHAO Hanjing, HAN Jianrong, JIN Yuqin, CHEN Yongjin 2022, 38 (23):  143-149.  DOI: 10.11924/j.issn.1000-6850.casb2021-0732 Abstract + ( 236 )   HTML ( 1 )   PDF ( 1288KB )   ( 36 ) Collective behavior is a common phenomenon in nature, about half of all fish species shoal for part or all their lives. In order to investigate the effect of population size on the collective behavior of juvenile bighead carp (Hypophthalmichthys nobilis), the Lolitrack software was used to compare the differences in spontaneous swimming speed and spatial distribution among experimental fish populations with different numbers of individuals in this study. The results showed that the spontaneous swimming speed of juvenile bighead carp was mostly in the range of 0-6 cm/s, and there was no significant difference in the average swimming speed among populations with of 1, 2, 4 and 8 individuals, indicating that the population size had no significant effect on the spontaneous swimming speed of juvenile bighead carp. The synchrony of all experimental groups were high and significantly decreased with the increase of population size (P<0.05). The nearest neighbor distance (NND) and mean neighbor distance between the focus fish and other experimental fish in the population were mostly distributed at 2-8 cm and 4-14 cm, respectively. The NND of the population with 2 individuals was significantly higher than the population with 4 and 8 individuals (P<0.05). The polarity of populations with 2 (83%) and 4 (88%) individuals were significantly higher than that with 8 individuals (68%, P<0.05). In conclusion, these findings indicate that juvenile bighead carp has obvious collective behaviors. On the one hand, the population size has little effect on the spontaneous swimming speed of juvenile bighead carp, and on the other hand, the population size has significant effect on its spatial distribution. In this study, the effects of population size on the cluster parameters of bighead carp are investigated, and the study is of practical significance for ecological breeding and fishery management of economic fish.

  The Damage Reduction Effect of Narrowing Harvester Track and Wide-narrow Row Planting in the Mechanized Harvesting of Ratooning Rice LIN Xiyue, LEI Zhengping, WU Xianqun, HUANG Suhua, SHAO Caihong, YANG Shulin, LI Mingqiang, LIU Jinping, GAN Jinhua, WEN Nanhui 2022, 38 (23):  150-155.  DOI: 10.11924/j.issn.1000-6850.casb2021-0935 Abstract + ( 303 )   HTML ( 1 )   PDF ( 1348KB )   ( 104 ) The purpose is to effectively reduce the rolling damage to rice stubble caused by mechanized harvesting in the main-crop (MC), and to improve the yield and productivity effect in the ratoon-crop (RC). Through the large area comparison test of narrowing harvester track and wide-narrow row planting, the effect of wide-narrow row planting on the biomass of the main-crop was investigated, and the damage reduction effect of narrowing harvester track was verified. The results showed that, compared with equal row planting, wide-narrow row planting effectively increased the biomass, panicle rate and yield of rice in main-crop. At the same time, wide-narrow row planting could effectively reduce the rolling area of the harvester track on residual stubble, reduce the yield loss of ratoon-crop caused by harvester rolling, and realize yield and efficiency increase simultaneously. The total yield of 16,309.22 kg/hm2 in the two seasons (MC+RC) could be achieved by adopting narrowing harvester track and wide-narrow row planting, which was 2,206.2 kg/hm2 higher than that of the control, with an increase of 15.64%. The yield of wide-narrow row planting in ratoon-crop was 5,897.87 kg/hm2, which was 807.41 kg/hm2 higher than that of the control, with an increase of 15.86%. Using narrowing harvester track could reduce the yield loss of ratoon-crop by 1288.16 kg/hm2 compared with the wide harvester track, and the damage rate decrease was 19.8%. The technical model established by the study is of low cost, easy operation and good effect, and suitable for promotion in ratooning rice production areas in hilly and mountainous areas.

  Soybean Planting and Soybean Commodities’ Import and Export Trade Structure in ASEAN Countries GUO Wen, DAI Xixi, MO Nan, ZHANG Yingqing, YU Chen, TIAN Jiang, GENG Zhide, LI Lu 2022, 38 (23):  156-164.  DOI: 10.11924/j.issn.1000-6850.casb2021-0804 Abstract + ( 516 )   HTML ( 9 )   PDF ( 1652KB )   ( 220 ) To better carry out the scientific research on soybean, the soybean planting scale in ASEAN countries from 1996 to 2019 and the import and export trade volume of soybean, soybean oil and soybean meal in ASEAN countries from 2010 to 2019 were statistically analyzed. The results showed that: from 1996 to 2019, Malaysia, Singapore and Brunei of the ASEAN did not plant soybean, therefore, Myanmar, Laos, Vietnam, Thailand, Cambodia, the Philippines and Indonesia of ASEAN were set as the research objects (hereinafter referred to as ASEAN 7 countries). The total harvest area and yield of soybean in ASEAN 7 countries showed a downward trend (while the harvest area and yield of soybean in Myanmar, Laos and Cambodia had an increased trend), but the average yield of soybean increased overall. From 2010 to 2019, the import and export trade volume of soybean, soybean oil and soybean meal in ASEAN 7 countries increased significantly, but were all in trade deficit, especially, soybean meal import took the first place and the import dependence was high. The import soybean and soybean meal in ASEAN 7 countries were mainly from genetically modified soybean planting countries, besides that, soybean was the most export commodity in ASEAN 7 countries and the soybean export market were mainly EU, China, Japan and South Korea. The import trade volume of soybean, soybean oil and soybean meal from China declined in ASEAN 7 countries, and the export trade volume of soybean and soybean oil to China increased, but there was few export of oil meal soybean meal. Therefore, it is suggested that Yunnan Academy of Agricultural Sciences should further increase cooperation and investment in scientific and technology research with ASEAN countries based on its scientific and technological strength and variety resource advantages, in order to carry out the joint research on autumn soybean, the industrial development demonstration and the substitute planting. The study has significance to diversifying China’s soybean import source countries and maintaining regional food security.