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    20 August 2023, Volume 44 Issue 08
    Climate Suitable Zones for Mechanical Kernel Harvesting of Middle-late Maturing Spring Maize in Northeast China under Future Climate Scenarios
    SU Zheng-e, LIU Zhi-juan, YANG Wan-rong, ZHU Guang-xin, SHI Deng-yu, YANG Xiao-guang
    2023, 44(08):  649-663.  doi:10.3969/j.issn.1000-6362.2023.08.001
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    Fully mechanized maize production has been trending in China, and using agricultural machinery to harvest maize grains is the focus of the transformation of maize production methods. Grain moisture content is the main factor affecting mechanical kernel harvesting, which is mainly affected by the agronomic characteristics of maize, ecological meteorological factors at the late growth stage, cultivation and management practice and other factors. Northeast China (NEC) is one of the main maize production regions and is the most sensitive regions to climate change in China. Clarifying the climate suitability and suitable zones for mechanical maize kernel harvesting in NEC under future climate conditions can provide scientific basis for improving the mechanization level of maize production and realizing the fully mechanized maize production in the future. In this study, based on the predicted climate data of 2021−2060 under two greenhouse gas concentration scenarios of RCP4.5 and RCP8.5 (the radiation forcing levels will reach 4.5W·m−2 and 8.5W·m−2 by 2100, which representing medium and high emission scenario, respectively) and the growth period data of spring maize, the northern boundaries of climate suitable zones for mechanical kernel harvesting of currently widely planted 29 middle-late spring maize varieties were determined using the kernel moisture content prediction models, and further the multi-variety based climate suitable zones were analyzed for the future 40 years. The results showed that climate very suitable, suitable, moderately suitable and marginally suitable zones for mechanical kernel harvesting will extend from southwest to northeast in NEC. And among different varieties, the northern boundaries of climate suitable zones fluctuate from the southwest to the southeastern mountainous areas of Jilin province (Changbai, Donggang and Songjiang areas) and the northern high latitude areas of Heilongjiang province. Under RCP4.5 (RCP8.5) climate scenario, the very suitable zones for 50% and 80% of middle-late maturing spring maize varieties located in the southern part of Liaoning province (the western and southern parts of Liaoning province). The northernmost can reach 42.0°N and 41.0°N (42.8°N and 41.9°N) latitude, and the easternmost can reach 123.4°E and 123.3°E (124.5°E and 123.3°E) longitude, respectively. The areas account for 5.9% and 1.8% (11.2% and 5.9%) of the potential growing area of spring maize in NEC, respectively. Suitable zones located in the northern and central parts of Liaoning province (the northern part of Liaoning province and southwestern part of Jilin province), with the northernmost reaching 43.0°N and 42.7°N (44.8°N and 42.9°N) latitude, the easternmost reaching 124.7°E and 124.4°E (124.7°E and 124.5°E) longitude, and the areas accounting for 8.3% and 8.9% (4.7% and 6.6%) of potential growing area of spring maize, respectively. In the future 40 years, compared with the RCP4.5 climate scenario, the middle-late maturing varieties of spring maize under RCP8.5 climate scenario have stronger climatic suitability for mechanical kernel harvesting, but the climate very suitable and suitable zones under the two climate scenarios are both small. The climate suitable zones for mechanical kernel harvesting will differ greatly between varieties, so varieties with short growth periods and fast dehydration rates which are suitable for mechanical kernel harvesting should be selected to improve the quality and efficiency of mechanical kernel harvesting in the future.
    Ecological Suitability and Potential Distribution of Chuanminshen violaceum Sheh et Shan in Sichuan
    ZHAO Jin-peng, WANG Ming-tian, LUO Wei, LI Yu-rui, LI Chao, WANG Ru-lin
    2023, 44(08):  664-674.  doi:10.3969/j.issn.1000-6362.2023.08.002
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    Based on the distribution of Chuanminshen violaceum Sheh et Shan (C. violaceum) obtained from field investigation and literature, and the data of three future climate scenarios presented by CMIP6, a relationship model between potential distribution and environmental factors was established to analyze the key environmental factors affecting the distribution of C. violaceum in Sichuan, and to simulate and verify the distribution law and suitable range of C. violaceum in the background of climate change. The result showed that: the key environmental factors affecting the potential distribution of C. violaceum were annual precipitation, precipitation of the coldest quarter, the minimum temperature of the coldest month and temperature annual range. The thresholds for the moderately suitable and above regions were 874.0−1231.2mm, 22.1−83.9mm, −4.4−3.5℃ and 25.0−31.2℃. In the historical period (2000−2020) under the current climate scenario, the suitable regions of C. violaceum mainly concentrated in the bottom of Sichuan basin, the mountainous regions along the basin and the eastern of Panxi plateau, with a total area of 21.49×104km2. Compared with the historical period, the highly suitable areas of C. violaceum would decrease by 14.07% and 10.04% under SSP1−2.6 and SSP2−4.5 scenarios,while it would increase by 3.46% under SSP5−8.5 scenarios in the 2050s. The moderately suitable area of C. violaceum would increase by 27.36%, 10.94% and 30.66%. The highly suitable areas would decrease by 40.89%, 33.53% and 36.71% in the 2090s, while the moderately suitable area would increase by 4.85%, 20.05% and 8.9%. In order to cope with the adverse effects of climate change on the growth and development of C. violaceum in the future, the protection of wild germplasm resources of C. violaceum should be carried out based on the existing major producing areas, such as Chengdu, Bazhong, Guangyuan and Nanchong. At the same time, work such as seed selection, seedling breeding and good gene storage, should be carried out, also artificial cultivation should be vigorously promoted to develop characteristic industries and indirectly protect wild resources.
    Impact of Increasing Atmospheric Temperature and CO2 Concentration on Soil Nitrogen and Phosphorus Content in Winter Wheat Field
    YUAN Jia-cheng, CHEN Can, YU Kai-hao
    2023, 44(08):  675-684.  doi:10.3969/j.issn.1000-6362.2023.08.003
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    T-FACE (temperature-free air carbon dioxide enrichment)experimental platform was adopted. Four field treatments of winter wheat were set: field conventional temperature and CO2 concentration (CK), field conventional temperature and increase CO2 concentration to 575μmol·L−1 (C), field increase temperature (i.e., 2℃ above atmospheric temperature) and field conventional CO2 concentration (T), and field increase temperature (i.e., 2℃ above atmospheric temperature) and increase CO2 concentration to 575μmol·L−1 (CT) . Soil samples were collected at different soil layers (plough layer 0−14cm, plough bottom 14−33cm, pond layer 33−59cm and glebe layer 59−80cm) at sowing stage, overwintering stage, tillering stage and maturity stage of winter wheat, respectively, to analyze the effects of increasing atmospheric CO2 concentration and temperature on N and P content and availability in the soil. The results were as follows: (1)under the condition that CO2 concentration increased in the overwintering stage of winter wheat, the nitrate nitrogen content in pond layer of soil showed a tendency to decrease by increasing temperature. In the overwintering stage of winter wheat, except for T treatment, the nitrate nitrogen content of CK, C and CT treatment was lower than that of tilling layer during sowing stage. In the overwintering stage of winter wheat, the nitrate nitrogen content increased most obviously in CK treatment. (2) Under the condition of increasing CO2 concentration and temperature, the content of ammonium nitrogen in the soil at tillering stage and overwintering stage of winter wheat was significantly lower than that under normal CO2 concentration and temperature treatment. There was no obvious upward or downward trend in different soil layers. The content of ammonium nitrogen was relatively stable during the whole growing stage of winter wheat. However, under CT, C and T treatments, the content of ammonium nitrogen increased significantly at maturity stage of winter wheat, and the increasing trend of nitrate nitrogen was more significant under increasing temperature (P<0.05). During the whole growth stage of winter wheat, the ammonium nitrogen showed a trend of increasing first and then decreasing under C treatment, while CK, CT and T treatments showed a trend of increasing, decreasing and increasing. (3) The content of available P in CK treatment was significantly higher than other treatments in the whole growth stage of winter wheat. There was a significant difference in available P content between CK treatment and CT and T treatments at sowing stage, overwintering stage and tillering stage of winter wheat (P<0.05). The results can provide some scientific basis for rational application of N and P fertilizer, reducing unnecessary nutrient loss and preventing non-point source pollution under the condition of CO2 concentration and temperature increase caused by climate change in the future.
    Effect of Regulated Deficit Irrigation on Greenhouse Tomato Production under High Temperature and High Humidity Environment in Meiyu Season
    JIANG Xiao-dong, ZHANG Jian-qu, LEI Hu
    2023, 44(08):  685-694.  doi:10.3969/j.issn.1000-6362.2023.08.004
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    In order to study the effects of regulated deficit irrigation (RDI) on the yield and quality of tomato under high temperature and high humidity environment in the Meiyu season, a field experiment was conducted in the solar greenhouse of Nanjing University of Information Technology during the Meiyu season from June to July in 2021. Using adequate irrigation (100% ET0) as the control (CK), three levels of RDI treatments were set up from flowering to fruiting stage of tomato, which were T1 (90% ET0), T2 (75% ET0) and T3 (50% ET0) respectively. The growth indices, nutritional quality, sensory quality and yield of tomato under different irrigation treatments were measured. The results showed that the plant height, leaf area, dry matter accumulation of root, stem and leaf of tomato increased first and then decreased with the decrease of irrigation amount. The plant height, leaf area, dry matter accumulation of root, stem and leaf of tomato in T1 treatment were the highest, followed by T2 treatment, and which were significantly higher than CK and T3 treatment. The yield of each treatment was T1>T2>CK>T3. The yield of T1 and T2 treatments were 23.21% and 9.33% higher than that of CK respectively, while that of T3 treatment was 19.36% lower than that of CK. The content of soluble protein, soluble solids, soluble sugar, titratable acid, the ratio of sugar to acid and the sensory quality such as color, luster, smell, peel thickness and sweetness all increased first and then decreased with the decrease of irrigation amount. Nutritional quality indicators such as soluble protein content, soluble solids content, soluble sugar content, titratable acid content, sugar-acid ratio, and sensory quality indicators such as fruit color, luster, aroma, pericarp thickness, sweetness also increased first and then decreased with the decrease of irrigation amount. The soluble solid content, soluble sugar content, sugar-acid ratio, fruit color, fruit smell, fruit sweetness and pericarp thickness of T2 treatment were the highest, followed by T1 treatment. The nutritional quality and sensory quality of fruits were evaluated by membership function method, and the results were T2>T1>T3>CK. According to the growth status of tomato plants, the nutritional quality, sensory quality and yield of tomato fruits, T1 treatment could significantly promote the growth of tomato plants, increase fruit yield and improve fruit quality under the environmental conditions of high temperature and high relative humidity in Meiyu season. Therefore, T1 treatment is the recommended irrigation amount for greenhouse tomato from flowering to fruiting stage under the high temperature and high humidity environment in Meiyu season of Nanjing.
    Analysis of Annual Compound Events of Heat and Drought in North China Based on Copula Function
    YU Xin, ZHANG Qi, YANG Zai-qiang
    2023, 44(08):  695-706.  doi:10.3969/j.issn.1000-6362.2023.08.005
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    The Copula function was used to analyze the annual compound events of heat and drought in North China, which can provide reference for agricultural water management and disaster prevention and mitigation in North China. Based on the daily maximum temperature and precipitation data of 36 meteorological stations in North China from 1960 to 2019, the year-by-year heat intensity and drought intensity were identified, the Copula function was introduced to construct a two-dimensional joint cumulative probability distribution function of heat intensity and drought intensity, and the return period of compound events of heat and drought in different grades were analyzed to assess the occurrence characteristics of the compound events. The results showed that when fitting the marginal distributions of annual number of heat days and drought intensity, the GEV function worked best at more stations; the most applied Copula function was the Symmetrised Joe-Clayton function when combining annual number of heat days and drought intensity in two dimensions; compared with high temperature intensity, drought intensity had a greater effect on the magnitude of the joint return period of compound events. North China is more prone to compound events with high heat intensity in the southwest and drought intensity in the south-central part of the country. The leading factors of compound events in North China vary from region to region, and different measures need to be taken to mitigate the damage caused by compound events in different regions.
    Hyperspectral Estimation Model for SPAD Value of Tomato Leaf under Virus Disease Infection
    XIANG Qian, YANG Zai-qiang, WU Lei, ZHANG Jian-Jian, WEI Wei
    2023, 44(08):  707-720.  doi:10.3969/j.issn.1000-6362.2023.08.006
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    Tomato 'Kaisa' was used as test material for pot trials in the artificial climate chamber of Nanjing University of Information Science and Technology from June to August 2022. Using whiteflies as media, through stinging and sucking for virus transmission to tomato plants. The maximum/ minimum air temperature was set at 28℃/18℃ and the relative air humidity at 70% (±5 percentage points) in the artificial climate chamber. The spectral reflectance and relative chlorophyll content (SPAD value) of tomato seedling leaves at different levels of the infection were measured by the SOC710 spectrometer and the SPAD-502 chlorophyll meter. The original spectra was first-order derivative transformed to analyze the relationship between each of the hyperspectral parameters and SPAD value of tomato leaves at different infection levels. In turn, the sensitive bands and characteristic parameters of tomato were screened in order to construct the best model for the estimation of the SPAD value. The results show that different infection levels of tomato leaves had different positions of the red edges. The leftward shift in the position of the spectral curve peak occurred at 710nm, with the maximum peak wavelengths occurring at 711nm, 700 nm, 695 nm, and 690 nm for healthy, slight, moderate, and severe infested tomato leaves, respectively. The elements R531, R816 (positive), R'500, and R'721 (positive) with the maximum highly significant correlation (P<0.01) were selected as spectral feature parameters by correlation analysis of spectral parameters with SPAD value. Spectral indexes were constructed using spectral feature parameters and the elements that were highly significantly correlated with SPAD values were Dy, λb, λr, Rg, RVI, DVI, PRI, GNDVI, NDVI, mNDI and SAVI. The hyperspectral estimation model of SPAD value of tomato leaves under virus disease infection was constructed by screening mNDI, GNDVI, R816, Rg, and R'500 by stepwise regression method, and the R2 of the validated model was 0.835. This study showed that the use of spectral technology was feasible for the measurement of SPAD value in tomato leaves affected by virus diseases, which provided a reference for early non-destructive diagnosis of plant diseases.
    Interpolation Method of Satellite-ground Collaborative Precipitation and Its Applicability
    XU Yong, GUO Zhen-dong, PAN Yu-chun, ZHENG Zhi-wei
    2023, 44(08):  721-734.  doi:10.3969/j.issn.1000-6362.2023.08.007
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    Changes in precipitation have great impacts on regional terrestrial ecosystems and water cycles. In this study, the middle and lower reaches of the Yangtze River Basin is considered to be the study area. The satellite-ground collaborative precipitation derived from in situ meteorological station, TRMM and GPM from 2001 to 2019 were collected. The interpolation results of satellite-ground collaborative precipitation against six Anusplin interpolation models were compared with the TRMM and GPM precipitation, TRMM and GPM downscaling precipitation, and interpolation precipitation based on the measured precipitation of verification stations. The research result can provide theoretical support for obtaining the precipitation with high accuracy, high resolution and excellent spatial details in the areas with sparse meteorological station. The results show that:(1)both the multi-year average accuracy of the results of the TRMM (R2=0.81, BIAS=0.06, RMSE=171.1mm)and GPM satellite-ground collaborative interpolation models(R2=0.81, BIAS=0.07, RMSE=172.8mm) in the middle and lower reaches of the Yangtze River Basin from 2001 to 2019 were superior to the multi-year average accuracy of interpolation precipitation of in situ meteorological stations(R2=0.66, BIAS=0.02, RMSE=198.66mm), TRMM downscaling precipitation(R2=0.79, BIAS=0.06, RMSE=174.8mm), and GPM downscaling precipitation(R2=0.81, BIAS=0.09, RMSE=192.4mm).(2)The satellite-ground collaborative interpolation precipitation has obvious advantages in the spatial detail expression, image integrity, and model stability. The interpolation result of TRMM satellite-ground collaborative interpolation model 5 has the best accuracy.(3)The variable and spline number of Anusplin interpolation model have a stronger impact on the accuracy of the interpolation result based on in situ meteorological station, but a weaker impact on the interpolation result based on satellite-ground collaborative interpolation precipitation.(4)The result of the downscaling model is closely related to auxiliary variables, which may cause a certain loss of accuracy and image deformity to downscaling precipitation data.
    Development Status, Problems and Prospects of Agrometeorological Observation Operation in China
    ZHANG Quan-jun, HONG Guan, WU Dong-li, HOU Ying-yu, ZHUANG Li-wei, ZHU Yong-chao, YANG Da-sheng, LIU Cong, SHI Yao-hui, HOU Biao, ZHANG Jing, LING Cong-jing, LI Yan
    2023, 44(08):  735-749.  doi:10.3969/j.issn.1000-6362.2023.08.008
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    Agrometeorological observation is an important cornerstone of agricultural modernization development. This study comprehensively sorted out the development process, business status and existing problems of agricultural meteorological observation in China, and discussed the development prospects of agrometeorological observation in the future, in order to provide a reference for escorting the sustainable development of modern agriculture and national food security. The development of China's agrometeorological observation operation has roughly experienced six stages: theoretical exploration, organization establishment, pilots construction, scale formation, optimization and adjustment, and stable and rapid development. At present, China has established a network of observation stations based on 653 agrometeorological observation stations (including 70 agrometeorological experimental stations) to carry out observation and research on crops, soil moisture, natural phenology, animal husbandry, fruit trees, trees, vegetables and agricultural microclimate. Based on the development of observation business, a national, provincial, municipal and county agrometeorological operational service system with scientific structure and advanced functions has been established. The national agrometeorological monitoring and evaluation, crop yield forecast, agrometeorological disaster monitoring and evaluation and impact forecast, agricultural weather forecast, meteorological grade forecast of occurrence and development of agricultural and forestry diseases and insect pests, agricultural soil moisture, drought relief, and ecological meteorological monitoring and prediction have been relatively mature and service results remarkable. In the past ten years, China's agricultural industry layout, planting structure and planting methods have undergone tremendous changes, and automatic observation technique such as automatic crop meteorological observation and automatic phenology observation have also developed rapidly. The agrometeorological observation operation also gradually shows a series of questions, such as the layout of the network of observation station and the observation tasks needs to be adjusted and optimized, the observation specifications need to be revised and supplemented, the modern technology and automatic observation equipment need to speed up the application and the operational service capacity needs to be improved and strengthened. From the perspective of the strategic deployment of the Party Central Committee of the CPC, the State Council and the China Meteorological Administration for the development of agrometeorological observation operation, the goal of high-quality development of agrometeorological observation, and the demand of modern agricultural development for agrometeorological operation, the future agrometeorological observation operation in China will gradually form a network of observation stations with reasonable layout, perfect specifications, advanced technical equipment, diversified and sophisticated service products, a modern agrometeorological observation and operational service system that can be in line with international standards.
    Impacts Report of Spring Weather Condition on Agricultural Production in 2023
    LIU Tao, LI Yi-jun, ZHAO Xiao-feng, HAN Li-juan
    2023, 44(08):  750-752.  doi:10.3969/j.issn.1000-6362.2023.08.009
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    Based on the daily national meteorological data in spring of 2023, relationships between meteorological factors and agricultural production in China were analyzed using statistical methods. The results showed that the national average air temperature in spring of 2023 was 11.3℃, which was 0.6℃ higher than the same period from 1991 to 2020, but with significant fluctuations. The national average precipitation was 127.2mm, which was 7.4% lower than the same period from 1991 to 2020 and the lowest since 2012. The spatial distribution of precipitation was uneven, with an overall distribution characteristic of more in the middle and less in the north and south of China. The national average sunshine duration was 634.6h, which was close to the same period from 1991 to 2020. The most summer-harvesting areas had sufficient light and heat during the yield formation stage, which was conducive for increasing the number of grains per ear and forming large ears. However, strong temperature drops and snowfall in mid-March and late-April caused varying degrees of freezing damage to winter wheat and rapeseed in Shaanxi, Shanxi, Henan and other regions. Wheat of Shaanxi and Henan experienced severe continuous rain in late-May, with the rainy period highly overlapping the wheat maturity period, resulting in moldy grains and sprouting of mature wheat. The soil moisture of spring sowing area in the northeast China was generally suitable, and the progress of spring sowing was relatively smooth. During the sowing and seedling raising period, there was no significant low temperature and low light weather in early rice regions, but there was a periodic low temperature in late-April and mid-May, which delayed the turning green and tillering process of early rice. Moderate to severe agricultural drought has occurred in southern of Sichuan and central and northern of Yunnan, affecting the sowing and emergence of maize, as well as the transplanting of one season rice and tobacco.