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    20 March 2021, Volume 42 Issue 03
    Effects of Long-Term No-Tillage on Soil Organic Carbon Contents of Winter Wheat in Different Soil Layers and Growth Period
    BAI Chong-jiu, WANG Jian-bo, DONG Wen-yi, LIU Xiu, LIU En-ke
    2021, 42(03):  169-180.  doi:10.3969/j.issn.1000-6362.2021.03.001
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    Based on a 21-year long-term no-tillage and straw-returning test, aimed to analyze the effects of long-term no-tillage and straw-returning on soil SOC(Soil organic carbon) and its components in the surface and subsoil(0−60cm) in the winter wheat growing period. This long-term fixed experiment started in 1992,included straw-returning under no-tillage(NT) and conventional tillage(CT), two field management methods. The chemical fertilizer was applied to the two treatment are same. After 20-year later, soil samples in different layers and wheat growth period were collected. Soil organic carbon(SOC), soil microbial biomass carbon(MBC), and soil particulate organic carbon(POC) were measured, soil soluble carbon(DOC) content in different soil layers and growth period. Compared with CT, NT significantly changed the distribution of MBC, POC, and DOC of 0−30cm soil layer in the five growth stages before sowing, before winter, jointing, anthesis, and maturity. Furthermore, NT significantly improved their soil contents in the five stages(P<0.05), specifically, in comparison, MBC, POC, and DOC in the five growth stages increased averagely by 60.8%−161.4%, 71.8%−141.1%, and 21.9%−104.4%, respectively. Besides, there is a great influence on SOC content in the 0−20cm soil layer by applying no-tillage and straw-returning; the average SOC content of 0−5cm and 5−10cm soil increased 81.2% and 52.9%, respectively. However, this similar influence did not appear in the 5-growth period. In the layer of 0−60cm, the contents of SOC, MBC, POC, and DOC under two tillage methods all showed a downward trend with soil depth growth. The organic carbon content of surface soil(0−20cm) and the level of active organic carbon(MBC, POC, DOC) in the wheat-growing time were significantly improved after applying no-tillage and straw-returning. This study showed that long-term no-tillage could raise the soil organic carbon content and active organic carbon level during the wheat growing season, which provides a theoretical basis for the efficient storage of organic carbon in dryland soil.
    Effects of Nitrogen Application and Rewatering and Redrought after Drought Priming on Water Use Efficiency of Wheat
    XING Jia-yi, LI Li, WANG Chao, XING Huan-li, HAO Wei-ping, WANG Yao-sheng
    2021, 42(03):  181-189.  doi:10.3969/j.issn.1000-6362.2021.03.002
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    A pot experiment in the greenhouse was conducted with the variety “XR4347” of winter wheat in order to investigate the effect of rewatering/redrought stress after drought priming and nitrogen application on water use efficiency of winter wheat. The experiment included two nitrogen levels with no nitrogen (N0) and nitrogen fertilization (N1, 1.5g·pot1), and three water treatments under each nitrogen level consisting of full irrigation (CK), rewatering after drought priming (PW), and redrought stress after drought priming (PD). The results showed that redrought stress after drought priming decreased the water potential of plants. Compared with the CK and PW treatments, the reduction of stomatal conductance (gs) of PD treatment was greater than the reduction of net photosynthetic rate (Pn), and therefore, the water use efficiency at the leaf and plant level was improved. Under the CK and PW treatments, the Pn and gs of leaves were significantly increased under nitrogen fertilization compared with no nitrogen application, whereas the intrinsic water use efficiency (WUEint, Pn/gs) of leaves increased slightly. Under the PD treatment, the effect of nitrogen application on gs was greater than that on Pn. The Pn increased by 4.5% while gs decreased by 13.6%, and therefore, WUEint increased significantly. Furthermore, the PD treatment significantly reduced the gs and the water consumption under nitrogen fertilization, and the WUEb and leaf δ13C were the highest with nitrogen fertilization, further indicating that the higher WUEb of the PD treatment under nitrogen fertilization was due to the stomatal control. Therefore, in arid and water-deficient areas, the combination of drought priming and nitrogen fertilization can not only significantly reduce plant water consumption, save irrigation water, maintain crop growth and nutrient absorption, but also improve water use efficiency at the leaf and plant level.
    Vertical Distribution and Transport Characteristics of Nitrogen in Spring Wheat Canopy
    JIANG Xiao-dong, LI Xu-ran, ZHANG Tao, YANG Xiao-ya, YANG Shen-bin
    2021, 42(03):  190-199.  doi:10.3969/j.issn.1000-6362.2021.03.003
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    The spring wheat variety Jichun 34 was used to carry out the three-stage sowing experiment (S1, sowing on December 16, 2016; S2, sowing on January 13, 2017; S3, sowing on February 19, 2017) at Nanjing from 2016 to 2017. The nitrogen content, nitrogen accumulation, nitrogen vertical gradients in leaves and stem-sheaths of spring wheat in different spatial layers of canopy after anthesis, as well as the translocation amount of plant nitrogen, grain protein content and yield were studied in order to clarify the characteristics of nitrogen accumulation, distribution and translocation in plant canopy of spring wheat, and to determine the optimal sowing date in Jiangsu Province. The results showed that the vertical distribution characteristics of canopy nitrogen content were obvious in spring wheat. After anthesis, the plant nitrogen content of spring wheat decreased with the decrease of canopy height. Sowing date significantly affected the accumulation, distribution and translocation of canopy nitrogen. Compared with early sowing date (S1), the nitrogen content and accumulation in the 40−80cm layer of canopy of late sown spring wheat (S2 and S3) were significantly reduced; the peak time of vertical gradients of nitrogen in leaves and stem-sheaths was advanced to the anthesis and filling stage; and the peak spatial position was reduced to the middle and lower canopy; and the amount of nitrogen translocation was significantly reduced by 6.61%−29.12%. The middle and upper vegetative organs of early sown spring wheat canopies could maintain a larger vertical gradients of nitrogen in the late growth period, and promote the transfer of nitrogen. At the same time, during the growth period of late sowing spring wheat, the amount of total solar radiation and precipitation received decreased, the daily average temperature increased, the heat stress increased after anthesis, the duration of growth period decreased, and the absorption and translocation of nitrogen by plants decreased. The grain protein content of late sown spring wheat was 8.46%−9.82% lower than that of early sowing spring wheat, and the protein yield was 40.78−71.47g·m−2 lower. According to the characteristics of nitrogen distribution and translocation in spring wheat canopy, sowing date of S1 (16 December) is the best for spring wheat in Jiangsu Province.
    Effect of Leaching with Low-concentration Nutrient Solution on Alleviating the Nutrient Enrichment in the Rhizosphere of Tomato Grown in Substrate
    WANG Chao-jun, XU Fan, GUO Wen-zhong, CHEN Fei, LI Ling-zhi
    2021, 42(03):  200-212.  doi:10.3969/j.issn.1000-6362.2021.03.004
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    With the extension of plants growth, the ion content in root zone showed a trend of increasing gradually in substrate culture. Tomatoes growth and development would be influenced by the changes of the ion concentration and its composition. In order to relieve the damage to the tomato plants caused by the nutrient enrichment in the substrate cultivation, taking "Yingfen 8" tomatoes as the experimental materials, a rock-wool potted experiment was conducted in the climatic chamber of National Agricultural Intelligent Equipment Engineering Technology Research Center from August 2019 to January 2020. The experiment included three treatments as leaching once a day (C1), leaching once a week (C2) and no leaching (CK), leaching liquor was 1/2 concentration nutrient solution. The environmental conditions of the artificial climate chamber were: daytime (9:00−17:00) temperature of 25℃, night (19:00−7:00 the next day) temperature of 15℃, sooner or later every 2h temperature transition; the average photosynthetic active radiation (PAR) of canopy was 300−400 μmol·m−2·s−1; the average CO2 concentration was 400−500mmol·mol−1; and the relative humidity was 65%/85% (day/night). From the 5th day after planting, 50mL of root zone solution and 50mL of backflow solution were collected at the end of leaching/irrigation drainage every day, and 105 times of samples were collected until the end of the experiment to determine their electrical conductivity (EC). Filtered irrigation fluid, root zone solution and reflux liquid were stored in a refrigerator at 4℃ every 7 days for nutrient ion determination, 16 times total. The role and effect of leaching with low-concentration were analyzed by testing the EC, ion concentrations, plant growth (height and stem thick), yield and other indexes. The results showed that the nutrients in the rhizosphere were enriched to different levels and the EC of the rhizosphere increased by 31.26%−69.06% compared with the irrigation liquid. Low concentration nutrient solution leaching could effectively reduce the EC, ion concentrations of root zone and reflux solution. Compared with treatment CK, the EC of root zone solution treated with C1 during the whole growth period reduced by 22.36%, the concentrations of , Ca2+, K+ and Mg2+ were decreased by 48.51%, 27.25%, 25.54% and 39.58%, respectively. The change trend of the reflux solution treated with C1 was consistent with that of root zone solution. In addition, compared with treatment CK, treatment C1 could promote the plant height growth and the yield of tomato. The yield per plant of C1 increased by 6.26%, among them, the single fruit weight of the 4th panicle and 5th panicle increased by 17.02% and 14.51%, respectively, also the yield per panicle increased by 13.42% and 33.86%, respectively. The EC and ionic concentrations of the root zone solution and reflux liquid treated with C2 were significantly lower than those of CK, but higher than those treated with C1. The EC of root zone solution of C2 was decreased by 9.64%. However, single fruit weight on average and yield of C2 treatment were not significantly different from those treated with CK. Therefore, leaching with low-concentration nutrient solution once a day (C1) can more effectively alleviate nutrient enrichment in the root zone in the middle and later stage of tomato growth in soilless cultivation, which could provide theoretical basis for nutrient management in the root zone of substrate cultivation.
    Mitigative Effect of Pyridine-2,3,4,5,6-Pentacarboxylate on the Brassica chinensis L. under Acid Rain Stress
    XIE En-yao , WEI Man, CHEN Jun-tong, ZHU Zhi-ping, YUAN Zhen-xing, ZHANG Ying, JIN Jin
    2021, 42(03):  213-220.  doi:10.3969/j.issn.1000-6362.2021.03.005
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    In this paper, the simulating acid rain (pH3.0) pollution was used, Brassica chinensis L., a national agricultural geographical indication product, regarded as the model material. The leaves which were sprayed distilled water regard as the control (CK). One treatment is the leaves were sprayed of pH 3.0 artificial acid rain (SY). Another treatment is the leaves were sprayed with 10mg·L−1 Pyridine-2,3,4,5,6-pentacarboxylate solution and pH3.0 artificial acid rain (WS) in sequence. The root activity, plasma membrane permeability (MP), catalase (CAT) activity, oxygen free radical producing rate and proline (PRO) content were studied under the condition of acid rain stress and pyridine-2,3,4,5,6-pentacarboxylate protection. The results showed that the leaf which sprayed 10mg·L−1 pyridine-2,3,4,5,6-pentacarboxylate solution could significantly improve the root activity and CAT activity, protect the cytoplasm membrane, and effectively reduce the PRO content and oxygen free radical production rate in broccoli under acid rain stress. The comprehensive comparison shows that pyridine-2,3,4,5,6-pentacarboxylate have a positive effect on relieving the physiological damage under the acid rain stress and improving the ability of resisting acid rain.
    Risk Analysis of Spring Frost in Main Grape Producing Areas
    YUE Hui-xin, HE Yan-bo, JIANG Jian-fu, FAN Xiu-cai, ZHANG Ying, LIU Chong-huai,
    2021, 42(03):  221-229.  doi:10.3969/j.issn.1000-6362.2021.03.006
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    In recent years, spring frost occurred frequently in China, which had a serious impact on grape industry and became one of the main meteorological disasters endangering grape production. Based on the daily minimum temperature observation data of 607 meteorological stations in China from 1958 to 2019, the occurrence days, frequency, station number ratio and disaster risk of spring frost disaster in main grape producing areas were analyzed by using statistical and spatial analysis methods. The results showed that the average days and frequency of frost in different grape growing areas were very different in the past 60 years. The frequency and average number of frost occurrence in spring were the highest in northwest and southwest mountain regions, and the lowest in southern regions. The intensity of spring frost was obvious in different regions. The intensity index of light frost tended to be smaller from north to south, while that of medium frost and heavy frost were generally smaller. The spatial distribution characteristics of the disaster causing factor index in the main grape producing areas were generally higher than those in the southern regions. The high-risk areas were mainly distributed in the northwest region and the north-east region, and the risk-free areas were mainly distributed in the southern region. According to the results of risk zoning, it can provide scientific basis for disaster prevention in main grape producing areas.
    SPEI Simulation for Monitoring Drought Based Machine Learning Integrating Multi-Source Remote Sensing Data in Shandong
    YANG Jin-yun, ZHANG Sha, BAI Yun, HUANG An-qi, ZHANG Jia-hua
    2021, 42(03):  230-242.  doi:10.3969/j.issn.1000-6362.2021.03.007
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    In this study, Shandong province was taken as the research area, and three machine learning methods, namely Bias corrected Random Forest(BRF), Support Vector Regression(SVR) and Cubist model were selected to integrate multiple impact factors to simulate the standardized precipitation evapotranspiration index on a three-month time scale(SPEI-3), so as to provide a method for accurate monitoring of drought in Shandong province. SPEI-3 values of 23 stations from 2001 to 2017 were taken as dependent variables. Multi-source remote sensing data including precipitation, surface temperature, evapotranspiration, potential evapotranspiration, normalized difference vegetation index and soil moisture were taken as independent variables. Independent variables and dependent variables constituted 80% of the data set as training set and 20% as test set. According to the BRF model, the simulated values of each site in the study area and the relative importance of each impact factor were obtained. The spatial distribution diagram of SPEI-3 was drawn and verify them. The results showed that the multiple factor simulation was more effective than the single factor. The R2 of the simulated value and observed value in the BRF model’s test set reached 0.856, and the RMSE of the root mean square error was 0.359. The BRF model can well simulate the SPEI-3’s values of the sites. Simulated and observed values for most sites are consistent with the drought trend, and reflect the number of months of different drought conditions is basically the same. The spatial distribution of SPEI-3 simulated by the BRF model is basically consistent with the drought degree of observed SPEI-3 at the site, and SPEI-3 spatial distribution of raster data outside the sites can also reflect the drought situation more accurately. According to the BRF model, the drought situation in Shandong province can be monitored more accurately at the site and spatial scale.
    Improvement of the Format and Transmission Mode of the Uploaded Data File in the Agrometeorological Observing Data Operation System
    CHENG Zhao-jin, ZHUANG Li-wei, ZHANG Yuan-yuan, WU Men-xin, LI Xuan, ZHAO Yu-fei
    2021, 42(03):  243-249.  doi:10.3969/j.issn.1000-6362.2021.03.008
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    With the rapid development of modern meteorological observation technology, the quantity and type of meteorological data is increased sharply. At present, the FTP file transfer method based on traditional TCP/IP protocol and pure text message file in TXT format can no longer meet the high-time transmission and storage requirements of large quantity and multi-type observation data. To meet the needs of meteorological informatization standard system construction, this paper studies the Java message service transmission and new technology development and application of XML data file formats in AgMODOS including the message middleware technology, message transmission architecture design, observation data message filtering and encapsulation, data cache and data supplementary transfer etc. in RabbitMQ message queue technology. The results of the trial operation of the service show that the CONTENT of the XML format file is correct, the message transmission is stable, and there is no loss. 99% of the observation data are transmitted from the station to the national bureau within 1s, and the data are transmitted to the business unit timely through the exchange control strategy, and the timeliness and service capacity of the agricultural meteorological observation data transmission are greatly improved.