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- Molluscicidal activity of tea saponin to Pomacea canaliculata and its safety evaluation against three aquatic organisms.
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作者：暂无
出版日期：2021-01-01
来源：关键词：植物源农药 水生生物 tea saponin botanical pesticide 茶皂素 safety evaluation 田间药效 field control efficacy aquatic organism 福寿螺 安全性评价 杀螺活性 molluscicidal activity Pomacea canaliculata
- 描述：Pomacea canaliculata, golden apple snail, has been listed as one of the 100 most destructive invasive alien species in the world by the International Union for Conservation of Nature. Recently, tea saponin, a botanical pesticide, has been reported to show effective molluscicidal activity. However, safety evaluation of tea saponin to environment is scarce. In this work, the toxicity of tea saponin to P. canaliculata was tested in the lab and the safety evaluation of tea saponin against three aquatic organisms was investigated. In addition, the field control efficacy of tea saponin to P. canaliculata was evaluated. The results showed that tea saponin was effective to P. canaliculata under the conditions of lab, and the LC50 values (all of the following values are shown in the form of active ingredients) against late adult, early adult and larvae snails were 2.61, 2.39 and 2.68 mg/L, respectively. Furthermore, tea saponin showed low toxicity to Daphnia magna (EC50 of 17.77 mg/L) and moderate toxicity to Barchydonio rerio (LC50 of 1.76 mg/L). Tea saponin could also promote the growth of Selenastrum capricornutum at the concentration of 100 mg/L. Application of tea saponin at dosages of 2.03, 2.25 and 2.48 kg/hm² resulted in a corrected control efficacy of higher than 90% to P. canaliculata in the field, which showed similar control effect to that of commercialized molluscicides, metaldehyde with 0.45 kg/hm² and niclosamide ethanolamine with 0.57 kg/hm². The present results will pave the way for the effective management of P. canaliculata with tea saponin in the field.
- Mechanism for the application of biochar in remediation of heavy metal contaminated farmland and its research advances.
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作者：暂无
出版日期：2020-01-01
来源：关键词：field application soil remediation heavy metals 土壤修复 生物炭 biochars 进展 田间应用 农田 farmland 重金属 advance
- 描述：Heavy metals contaminated soils pose a serious risk to human beings and animals via direct exposure and food chain. Biochar, a carbon-rich material, is used to remediate heavy metals contaminated farmland. This strategy provides an effective method for utilizing biomass resources and ensuring food safety. With increasing attention, the number of published articles concerning biochar has been increasing in the recent ten years, therefore providing researchers with a large amount of evidence and insights. In this study, the latest studies of biochar in the remediation of heavy metals contaminated farmland were reviewed, with the focus on possible mechanisms of biochar-heavy-metal interactions, related impact factors, and in-situ application of biochar at the field scale. Biochar showed a strong sorption ability, attributed to its physiochemical properties such as large specific surface area, abundant functional groups and high cation exchange capacity. The application effect of biochar was greatly influenced by its characteristics. After summarizing biochar’s physiochemical property data in recent years, the study discussed the changing law of biochar’s properties with the alteration of feedstocks and pyrolysis temperature, respectively. To modulate the properties of biochar for soil remediation, various modifiers with different concentrations were adopted, including acids, bases, oxidizing agents, organic solvents and metal salts or oxidizing agents. In general, the purposes of modification were to enlarge the surface area, to change the functional groups, and to increase the adsorption performance and catalytic capacity. Furthermore, the immobilization mechanisms of heavy metals by biochar were illustrated. The direct immobilization could be achieved through physical absorption, electrostatic attraction, ion exchange, complexation, precipitation, and redox reaction. Besides, the indirect effects of biochar on heavy-metal mobility and bioavailability, which could be achieved via impacting soil characteristics and thus heavy-metal-soil complexation, were less understood and could be largely underestimated. Biochar addition could alter many soil properties including pH value, dissolved organic carbon, mineral composition, and cation exchange capacity. These changes would affect heavy-metal-soil interactions and thus heavy-metal mobility and bioavailability. Many laboratory studies had demonstrated biochar’s effectiveness in decreasing the bioavailability of heavy metals as well as improving soil quality. However, the value of biochar in the remediation of contaminated land had not been well tested in the field. In different field trials, distinct results (beneficial, neutral or adverse effects) had been reported due to wide variations in field conditions and biochar characteristics. To better understand whether biochar application could provide a promising direction for soil remediation, this review was undertaken to assess the published field trial. The results of most previous field trials indicated that biochar could potentially reduce heavy-metal bioavailability in the field. Meanwhile, a significant decrease in the heavy-metal enrichment of the crops was observed. It was found that the use of biochar may help increase crop yields on polluted farmland and reduce the amount of mineral fertilizer used in the field. The application of biochar could inactivate heavy metals through improving soil physicochemical properties (pH, cation exchange capacity, water retention capacity etc.). In addition, it also could be used to enhance the uptake of soil nutrients for plant growth. However, according to a majority of studies, biochar’s effectiveness in reducing the impacts of heavy metals depended on a myriad of factors in the field, including biochar applying process (variety and dosage rate of the biochar, mixing depth), agronomic measure (nitrogen-phosphorus-potassium fertilizer application) and climatic conditions (air temperature and precipitation). In the last part, future research on the perfection of the mechanisms of soil remediation using biochar, the expansion of the scale, and the long-term monitoring on soil was prospected.
- L型链耙残地膜回收机的设计
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作者：张峰
出版日期：2022-01-01
来源：关键词：田间试验 链耙弹齿 残膜回收机 仿真分析 起膜铲
- 描述：随着地膜覆盖面积的扩大和所覆地膜年数的增长,田间滞留的残地膜对环境造成了非常严重的污染。采用机械回收残地膜,可以克工克力。现有的残地膜回收机的除杂方式主要是利用弹齿或者气力式除杂。弹齿式残地膜回收机对边膜回收,脱膜困难,没有自动卸膜功能。气力式残地膜回收机在工作时灰尘较大,工作时风机口容易堵塞,需要定期清理,影响机器工作效率,机器不能连续工作。本文提出了将起膜铲、筛条、链耙弹齿、脱膜装置、自动卸膜装置相结合的办法设计了一款回收率高、杂物少、自动卸膜的残地膜回收机。文中主要对以下几点做了深入研究并且做出了结论:（1）对残地膜回收条件进行了测定,包括了地膜铺设情况,得出新疆喀什地区的棉花种植模式为（660+100）mm四行植株的种植模式,铺设的地膜宽度为1200mm,边膜覆土厚度为50 mm,确定了 L型链耙残地膜回收机的整体结构与设计要求,结合国内外机型的优缺点以及L型链耙残地膜回收机的整机结构确定了其工作原理。（2）对L型链耙残地膜回收机的关键零部件进行设计,包括传动系统、起膜装置、L型链耙弹齿。其动力输出轴的转速为337.5r/min,功率为32.70 kW,转矩为925.3 N·m。选取起膜铲作为起膜装置,起膜铲铲宽为1300 mm,铲面倾角取值为17.1°～22.7°,铲刃角度为25°。L型链耙输膜倾角为60°,弹齿与链耙之间的倾角为75°。其他部件包括机架、拨土辊、土膜输送分离装置、脱膜辊、集膜箱。对链耙弹齿进行了运动学分析,其x方向与y方向位移与理论位移的误差分别为3.1%、2.1%,此误差在可接受范围内。（3）对L型链耙残地膜回收机的起膜装置（起膜齿、起膜铲）进行了静力学有限元分析,并在两种起膜装置中进行了选择,通过分析得出起膜铲的最大应力为51.30 MPa,最大变形为0.28 mm,起膜齿的最大应力为43.58 MPa,最大变形为0.08 mm,均满足所选材料的设计要求。经过分析,选择起膜铲做为起膜装置。对弹齿也进行了静力学有限元分析,弹齿的最大应力为1109.5 MPa,最大变形量为13.67 mm,满足设计要求。（4）进行田间试验,试验结果显示,L型链耙残地膜回收机的作业速度为4～7km/h,作业深度为60～80 mm,五个测点的残膜回收率分别为:93.60%、92.86%、87.84%、95.50%、86.45%。五个测点的残膜回收率都大于85%,各项性能指标均符合《GB/T 25412-2010残地膜回收机》国家标准。该机具残膜回收率高、除杂率高、作业情况好,可进行长时间作业,满足了设计要求。
- Infield Corn Kernel Detection and Counting Based on Multiple Deep Learning Networks.
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作者：MM Fogler
出版日期：2022-01-01
来源：关键词：CNN YOLOv5 深度学习 harvest loss L 田间玉米籽粒 Mask R 收获损失 D5 deep learning Det YOLOX infield corn kernel Efficient kernel count 籽粒计数
- 描述：Machine vision has been increasingly used for agricultural sensing tasks. The detection method based on deep learning for infield corn kernels can improve the detection accuracy. In order to obtain the number of lost corn kernels quickly and accurately after the corn harvest, and evaluate the corn harvest combine performance on grain loss, the method of directly using deep learning technology to count corn kernels in the field was developed and evaluated. Firstly, an RGB camera was used to collect image with different backgrounds and illuminations, and the datasets were generated. Secondly, different target detection net‐ works for kernel recognition were constructed, including Mask R-CNN, EfficientDet-D5, YOLOv5-L and YOLOX-L, and the collected 420 effective images were used to train, verify and test each model. The number of images in train, verify and test datasets were 200, 40 and 180, respectively. Finally, the counting performances of different models were evaluated and compared according to the recognition results of test set images. The experimental results showed that among the four models, YOLOv5-L had overall the best performance, and could reliably identify corn kernels under different scenes and light conditions. The aver‐ age precision (AP) value of the model for the image detection of the test set was 78.3%, and the size of the model was 89.3 MB. The correct rate of kernel count detection in four scenes of non-occlusion, surface mid-level-occlusion, surface severe-occlusion and aggregation were 98.2%, 95.5%, 76.1% and 83.3%, respectively, and F1 values were 94.7%, 93.8%, 82.8% and 87%, respectively. The overall detection correct rate and F1 value of the test set were 90.7% and 91.1%, respectively. The frame rate was 55.55 f/s, and the detection and counting performance were better than Mask R-CNN, EfficientDet-D5 and YOLOX-L net‐ works. The detection accuracy was improved by about 5% compared with the second best performance of Mask R-CNN. With good precision, high throughput, and proven generalization, YOLOv5-L can realize real-time monitoring of corn harvest loss in practical operation.
- Indoor screening of biofungicides for strawberry root rot and verification of field control efficacy.
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作者：JE Regan
出版日期：2022-01-01
来源：关键词：biopesticide 田间防治效果 pathogen isolation and identification field control efficacy 草莓根腐病 生物源农药 病原菌分离鉴定 strawberry root rot inhibitory activity 抑菌活性
- 描述：Strawberry root rot is one of the main diseases of strawberry in Guanzhong, Shaanxi Province. In this report, the pathogen strains of strawberry root rot were isolated through tissue isolation method. And they were identified as Fusarium solani and Fusarium oxysporum through morphological and molecular biological methods. The inhibitory activity of four plant derived fungicides against two Fusarium species was determined by mycelial growth rate test. Matrine + osthol 1.5% AS had the strongest inhibitory activity to F. oxysporum with EC50 value of 2.7 μg/mL, while matrine 0.3% EC had the strongest inhibitory activity to F. solani with EC50 value of 4.5 μg/mL. Three plant derived fungicides and three microbial fungicides (Bacillus subtilis, Bacillus polymyxa and Trichoderma harzianum) were selected for field test against strawberry root rot. The 600 times dilution of B. subtilis 100 billion spores/g WP had the best control efficacy against strawberry root rot, up to 69.25%. The control efficacy of 800 times dilution of B. polymyxa 1 billion spores/g WP, 700 times dilution of matrine + osthol 1.5% AS and 200 times dilution of T. harzianum 200 million spores/g WP were 63.14%, 62.84% and 59.74%, respectively. Therefore, B. subtilis WP, B. polymyxa WP, matrine + osthol AS and T. harzianum WP are recommended as field control agents for strawberry root rot.
- Formula selection of Phoma herbarum SYAU-06 water dispersible granule againgst day flower.
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作者：
出版日期：2020-01-01
来源：关键词：配方筛选 formula selection 鸭跖草 真菌 微生物源除草剂 dayflower mycoherbicide 田间防效 water dispersible granule fungi field control efficacy Phoma herbarum 水分散粒剂 草茎点霉
- 描述：Phoma herbarum SYAU-06 isolated from diseased leaves of dayflower was expected to be a candidate of mycoherbicide, which could cause the death of dayflower by effective infection and was safe to most crops. In this study, the biocompatibility of different carriers and adjuvants with P. herbarum was explored. Under the conditions safe to SYAU-06, the physicochemical properties of different carriers and adjuvants were compared. The optimum formula for P. herbarum SYAU-06 water dispersible granules (WG) was determined as follows (by mass fraction): SYAU-06 fermentation mycelial cultures 15%, wetting agent BX 6%, dispersant NNO 4%, disintegrating agent ammonium sulfate 6%, binder polyethylene glycol (PEG 4000) 4%, stabilizer calcium carbon 5%, carrier silica 60%. The properties of P. herbarum SYAU-06 WG prepared in accordance with this formula were measured. The results showed that the content of SYAU-06 living mycelium was 2.55 × 108 cfu/g, the wetting time was 28.16 s, the disintegration time was 70.50 s, the suspension percentage was 88.90%, the pH value was 6.97, and the moisture content was 1.47%. All of the indicators of the sample were up to the standard. The field control efficacy of P. herbarum SYAU-06 WG on dayflowers in soybean field was determined by the foliage spraying method. The fresh weight control effect against dayflower 21 days after the application was 50.89%, 55.97%, 60.67% and 69.88% respectively at the formula dosage of 1 305, 1 740, 2 175 and 3 480 g/hm².
- Finite Element Analysis of Rice Film Mulching Direct Seeding Machine Frame Based on ANSYS.
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作者：暂无
出版日期：2020-01-01
来源：关键词：田间试验 水稻覆膜直播机 Rice mulching direct seeding machine static analysis 模态分析 modal analysis field trial 静力学分析
- 描述：In order to make the frame of the rice mulching direct seeding machine meet the load-bearing requirements of the mulching direct seeding work, avoid excessive deformation of the frame and affect the flatness of the cover, and to avoid resonance between the frame and the excitation source such as the engine, ANSYS is used to perform static analysis and modal analysis on the rice mulching direct seeding machine frame. Through static analysis of three material frames and comprehensive evaluation based on the analysis results, the frame of material Q235 is the best. In the modal analysis of the Q235 rack, the first six natural frequencies of the rack are obtained. The excitation frequency of the main excitation source is compared with the first six natural frequencies of the rack, and the comparison results show that the resonance phenomenon does not occur in the work of the rack. Finally, field tests verify that the designed frame can meet the requirements of the mulching direct seeding operation.
- Field Efficacy Test of Five Different Pesticides against Spodoptera exigua
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作者：马丽颖
出版日期：2020-01-01
来源：关键词：Field Efficacy Test 杀虫剂 Pesticide 甜菜夜蛾 田间药效试验 Spodoptera exigua
- 描述：In this experiment, five insecticides with different insecticidal mechanisms with high efficiency and low toxicity were selected for the field efficacy test of Spodoptera exigua on lettuce. The results showed that the five insecticides used in the experiment had certain control effect on Spodoptera exigua on lettuce. One day after the treatment, the control effect of the five pesticides reached the highest level, meaning that they all can kill pests quickly. Seven days after the treatment, three of them, 200 g/L chlorantraniliprole SC, 10.5% trifluoromethane EC and 30 billion PIB/g Spodoptera exigua Nucleopolyhedrosis virus WG, were still doing well with more than 89% control effect, and even had no adverse effect on lettuce.
- Field Drainage Strategies to Adapt Climate Change and Crop Production in the Lower Reaches of the Yangtze River Basin,China
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作者：Ahmed Awad Hag Abdelnabi
出版日期：2022-01-01
来源：关键词：田间水平衡 气候变化适应 CROPWAT DRAINMOD 农业排水
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描述：中国是世界上最大的煤炭生产国和消费国,由于人口众多,其人均温室气体排放量虽然远低于其他发达国家,但是总排放量无论从生产还是消费来看都非常大。目前,中国政府正在积极实施减碳政策,走绿色发展之路。不过,与世界各国一样,中国正在受到全球变暖对水资源、农业和林业的负面影响,预计未来的影响还会继续加剧。作为一个农业大国,探索气候变化等不利条件对农业生产和水资源利用的不利影响,并提出相应的应对措施是保障国家粮食生产和保护生态环境工作中迫切需要解决的实际问题。作为粮食生产的一个主产区,长江流域贡献了中国近一半的粮食生产量,其中包括超过三分之二的水稻总产量。该区域种植的其他作物包括棉花、小麦、大麦、玉米、和各种豆类。因此,这一地区作为当地和国际需求的大多数作物的主要供应地具有极大的战略重要性。长江下游区常被称为中国的“鱼米之乡”,其自然条件非常有利于农业生产。区内有许多湖泊和连接水道,是中国土地最肥沃的区域之一。尽管这些地区气象条件适合农业生产,已有研究报告指出,这些地区中有可能存在不少气候变化的“热点”。这将是对未来农业生产的一个主要威胁,同时还可能由于气候变化而对周围环境造成其他严重灾害。考虑到上述问题以及区域的经济和战略重要性,针对农业生产发展和水土环境保护,有必要回答以下问题:●这些农业区的气候是否会发生变化,如何发生变化?●这些气候变化是否会影响未来农田的水分平衡和农业生产力?●如何使这些区域的农田适应未来的气候变化,减轻其不利影响,确保更好的农业和环境条件?因此,本文的第一组研究目标是:1)基于典型浓度路径（RCP45）和RCP85的长江下游人工排涝农田未来2021-2050年气候变化评估;2)应用DRAINMOD模型评估这些气候变化如何影响未来的农田水文状况;3)应用CROPWAT模型评估这些气候变化如何影响研究区未来的灌溉需求;4)应用DRAINMOD模型评估一些建议的农业排水条件的有效性,应用CROPWAT模型评估适应方法如何有助于缓解气候变化对未来灌溉需求的不利影响。本文的第二部分重点讨论了农田水文和作物模型的一些局限性和不恰当的假设,因为这可能是削弱气候变化对未来农田水分平衡和农业生产力影响评估的原因。研究人员总是依靠实地或实验室实验作为一种方法,以帮助评估水资源或作物产量对某些农业或人类活动的明显反应。简单的农业活动和人类活动,可以很容易地被模仿;研究人员可以进行这样的实验,并记录他们的发现。但当工作涉及到气候变化时,数字就不同了。如果我们想要评估未来气候变化对水资源或作物产量的影响（如本文的第一组目标）,这是非常困难的,有时是不可能在物理上实现的。换句话说,我们无法改变全球气温或降水模式,然后检查作物产量或农田水分平衡对这些新天气条件的响应。此外,这将花费大量的预算来实现小规模的实验。因此,水文和作物模型是一种更有效的方法,以此我们可以评估未来的农田或流域水文和作物产量将如何受到气候变化的影响。与实地或实验室实验（我们可以通过检查使用设备的设置以及它们在多大程度上遵循参考方法来直观地判断它们的准确性）相反,水文和作物模型的准确性可以通过不同的检查来判断,例如:●模型的输入模块:模型的输入模块在多大程度上覆盖了所有对模型输出有直接或间接影响的参数。最好的模型是有一个输入模块,其中包括整个参数和字段条件,可以影响任何模型的输出;●模型采用的计算顺序:模型采用的计算顺序是否基于详细报告的模型应用领域的方法和关系?或者计算序列非常简单,只依赖于可能考虑（以一种不恰当的方式）一些影响模型输出的参数的经验方法?毫无疑问;从模型（不太依赖经验方法）得出的结果一般比那些基于经验模型得出的结果更灵活可靠。基于上述,“绝对最佳”一词不能描述某一特定模型,因为某一特定模型在一定的田间条件下可以完美的调参,而在不同的田间条件下则不能。所以,当研究人员决定使用一个模型为特定的研究领域,需要检查这个模型考虑整个/大部分的参数会影响模型的输出,然后检查模型的计算顺序,以确保所有的假设是一致的。如果忽视某些现场条件或田间管理,大多会导致模型产生不适当的输出,不能反映真实情况,从而导致决策者采取不适当的应对措施。在这篇论文中,我们的目标是讨论在DRAINMOD模型（作为水文模型）和CROPWAT模型（作为作物模型）中的两个限制条件如何对模型的输出产生不利影响。接下来,我们的目标是克服这些模型的局限性,以提高它们的性能,从而确保更好地评估农田的水分平衡和生产过程。DRAINMOD模型在描述农田地表蓄水能力时变性中的局限性。DRAINMOD模型是一个基于过程的田间水平衡模型,可以模拟不同的农业排水策略对农田水平衡的影响。该模型已被许多研究人员在全球范围内应用,以实现广泛的目标,包括:●评估不同排水系统参数（如排水暗管安装深度、排水管间距）对田间水量平衡的影响;●评估不同的排水战略和管理做法（例如,常规、控制排水和灌溉）对作物生产力和农田水分平衡的影响;●评估现有排水系统在未来气候变化下的适宜性,并提出适当的排水布局,以确保在预计的气候变化下理想的未来农田水分平衡。DRAINMOD模型考虑到影响农田水分运动的大多数田间条件和管理实践,在每小时和每天的时间尺度上进行水量平衡计算,输出可以清楚地反映研究的农田水分分布规律。不过,DRAINMOD模型不能考虑地表存储水量（SSC）值的变化情况。农田地表蓄水量可以表示为径流开始前土壤表面坑洼能够保留的水量。与坑坑洼洼的土地相比,较为平坦的土地具有较低的蓄存能力,无法在径流开始前保留大量水分。当降雨或灌溉事件发生时,水在洼地的地表积聚;然后这些水开始渗透到土壤中,但如果土壤渗透性低或饱和,水就会在地表积聚更多。当这些水的总量超过地表坑洼存储能力时,就会发生径流。因此,地表蓄水能力在水循环中的作用至关重要,因为它是径流开始的主要决定因素之一。基于地表蓄水能力对农田水分平衡形成的重要作用,有必要考虑地表坑洼在模拟期间的不同时段的变化情况。由于DRAINMOD模型中地表蓄水深度的输入值固定,在应用于时变地表积水特征农田的水分动态预测时,很有可能导致模型输出不合理。在此基础上,本文研究了如下内容:1)考虑模拟过程中地表蓄水量的变化,提高DRAINMOD模型的性能。这通过开发一种人工神经网络（ANN）模型来实现,该模型可以（ⅰ）克隆在DRAINMOD中用于预测田间水分平衡的计算序列,并（ⅱ）考虑模拟期间（SSC）的变化;2)在CROPWAT模型中对雨水利用率的经验预测误差导致模型产生不适当的灌溉需求估计。农业用水在全球用水总量中占主导地位。平均而言,灌溉农业生产每年在世界主要水域消耗1230立方千米的淡水。由于对现有水的不公平和未经管理的使用,导致许多地区缺水;例如,一些农田的供水量超过了作物的需水量。拥有适当的管理工具,使我们能够在保证作物产量不受损失的情况下减少农业部门的用水,从而有很大的机会缓解农田的缺水问题。因此,研究人员开发了许多模型,可以估计实际作物的用水需求,从而减少灌溉用水浪费,提高用水效率,并更好地共享有限的淡水资源。在这些模型中,CROPWAT是一个基于WINDOWS的决策支持系统,由世界粮食及农业组织（FAO）开发,以帮助农业气象学家、农学家和灌溉工程师进行作物用水研究,特别是灌溉计划的设计和管理。此外,该模型还允许:提出若干改进灌溉实践的建议,在各种不同的供水条件下规划灌溉计划,以及在缺粮或雨养条件下的作物产量评估。该模型已经应用在全球范围内作为一个简单的和值得信赖的工具,有助于决策者了解多少水需要一些作物,如水稻、玉米、大豆和番茄,土豆,生长最佳如果有天气变化,日益增长的日期、现场条件,管理实践等。CROPWAT利用供水和灌溉管理条件的各种选项进行每日土壤-水分平衡,以估计实际的作物水分需求。该模型根据气象和作物数据的输入计算蒸散发。到目前为止,该模型可预测向作物提供的精确水量,以补偿在蒸散过程中损失的水量。在雨养农田,雨水在满足作物的部分用水需求方面起着重要作用。然而,有些雨水总是通过径流和深层渗透流失的。因此,只有一部分的雨水（称为“有效降雨”）留在土地上,并补偿了在蒸散过程中损失的一部分水。因此,“有效降雨”减少了最终应供应给土地的水量,以补偿蒸散造成的水分损失)。准确地预测这种“有效降雨”,可正确估计灌溉需求。而CROPWAT采用了一些经验方法来预测雨水损失从而预测有效降雨量。这些方法包括:美国农业部水保署（USDA-SCS）方法、可靠的降雨（FAO/AGLW公式）、经验公式法、以及固定百分比法。问题是这些经验方法能否预测农田中真实的雨水利用或损失?。因此,我们考虑并关注其中一种方法,即美国农业部水保署（USDA-SCS）计算方法。该方法对有效降雨量的估算是根据美国境内22个站点50年来的天气数据,进行水量平衡计算而开发的。根据文献报道,该方法没有明确说明影响雨水利用的直接/间接因素,如地理位置、场地拓扑、土壤类型、降雨频率等。因此,这种经验方法（即 CROPWAT模型所采用的预测雨水利用的方法,没有适当考虑实际的田间条件和管理实践,很可能导致对雨水损失的预测不准确,从而产生“有效降雨”误差,最终导致CROPWAT对灌溉需求的估计不准确。考虑到上述因素,本文提出了改进灌溉需水量估算过程的方法,从而保证较高的农业生产率和更好地利用有效的农业用水,研究内容包括:1）评估CROPWAT模型中用于预测雨水利用的经验方法在多大程度上影响模型对雨水损失的预测（即“有效降雨”）,进而影响灌溉需求的估计?2)提出一种新的方法,根据详细的基于水文的雨水利用预测（使用DRAINMOD模型产生）来估计灌溉需求,而不是在CROPWAT模型中采用的经验方法,这在多大程度上可以改善灌溉需求的估计。本文选择江苏省扬州市沿运灌区作为研究区,区域内海拔高度为5-8米+平均海平面,年降水量约1000 mm,年平均最高和最低气温分别为21℃和12.3℃。作物轮作是水稻和小麦,水稻生长期为每年6月底到11月初,小麦则是从11月中旬到次年6月初。研究区虽然雨量充沛,但水稻生长季节仍需进行灌溉,灌溉水来自附近的运河。试验站具有自动气象站记录不同的天气参数,包括降水、气温、风速、相对湿度等。研究方法可以简单描述如下:1)关于气候变化及其对研究区域未来水平衡的不利影响以及应变措施,内容包括:●根据研究区2018-2019年水文监测数据对田间水文模型DRAINMOD进行了验证●利用区域气候降尺度实验“CORDEX”预测研究区未来（2021-2050年）的最高和最低气温和降水;●利用未来的气象数据,应用DRAINMOD模型预测研究区域未来的水量平衡,以评估气候变化对研究地区未来的田间水文过程产生的不利影响;●应用DRAINMOD模型评估一些建议的做法（与改善地表排水条件有关）的效率,以适应预测的气候变化,并减轻其对研究区域未来水平衡的不利影响。2)气候变化对研究区域未来灌溉需求的不利影响:●利用未来天气数据,将CROPWAT模型用于估计研究区域未来的灌溉需求（IRs）,目的是评估与2018-2019生长季相比,预计的气候变化将如何对研究区域未来的IRs产生不利影响;●重新应用CROPWAT模型,评估提出的地表排水条件改善将如何缓解气候变化对未来灌溉需求的不利影响,从而更好地保护农业用水。3)关于DRAINMOD模型和CROPWAT模型性能的改进●开发、校准和验证模拟DRAINMOD模型性能的人工神经网络模型,具有考虑地表存储能力（SSC）多个值的优势。这样做是为了克服DRAINMOD在模拟过程中考虑SSC的固定值的限制。●为了准确估算灌溉需求,我们提出了一种新方法,采用了详细的雨水命运水文预测（由DRAINMOD模型产生）,而不是在估算灌溉需求时采用的CROPWAT模型的经验预测。这样做是为了克服CROPWAT在雨水命运预测不准确方面所体现的局限性,即“有效降雨”,这是由于模型中采用的经验方法忽略了许多对雨水命运有直接/间接影响的实地条件和管理做法。本文取得的主要研究成果如下:1)研究区未来气候变化预测及其对农田水分平衡和灌溉需求的不利影响;研究区域将受到未来气候变暖的影响:RCP45情景下年最高气温和最低气温分别升高1.09℃和1.15℃,RCP85情景下最低气温和最高气温分别升高1.34℃和1.39℃。此外,将出现更频繁的一日暴雨峰值事件。DRAINMOD模拟结果表明,气候变化将使未来农田径流增加33%（RCP45）和36.9%（RCP85）,同时减少入渗水量;因此,农田地下水位将下降6%（RCP45）和14.5%（RCP85）,这可能会增加区域出现干旱的风险,不利于水稻生产。2)CROPWAT模型模拟结果表明,预计的气候变化将增加研究地区未来的灌溉需求（高达15%和65%）。关于改善研究区未来地表排水条件的效率（作为一种适应方法,有助于减轻对未来水平衡和灌溉需求的预期不利影响）。DRAINMOD模拟显示,加强研究区域未来地表水储存条件将有助于缓解气候变化对农田水平衡的不利影响（通过缓解未来径流的增加和GWT未来的下降）。CROPWAT模拟结果显示,在地表排水条件下采用这种增强方法将有助于缓解研究区域未来IR增加的16%。3)针对DRAINMOD模型在整个模拟周期内缺乏考虑SSC固定值的不足,开发、训练和测试了一个人工神经网络模型（称为“DRAINMOD-ANN模型”）,以模拟DRAINMOD模型在预测农田水分平衡方面的性能。然后,为了克服上述限制,建立了考虑多个SSC值的开发模型（而不是像在DRAINMOD模型中那样只考虑一个）。通过对比GWT预测和DRAINMOD预测,验证了所开发的模型在研究区域的有效性。两个模型的GWT预测之间有很好的一致性,决定系数（R2）=（0.97-0.99）,平均绝对误差（MAE）=（2.4cm-4.6cm）,纳什-萨克利夫效率（NSE）=0.99,均方根误差（RMSE）=（5.1cm-7.5cm）。4)为了克服CROPWAT模型与模型中采用的经验方法（经验预测雨水命运）有关的局限性,提出了一种估算IR的新方法,利用DRAINMOD对雨水归宿的详细模拟（而不是CROPWAT模型中采用的经验方法）。与CROPWAT相比,该方法大大提高了IRs的估计。这是因为采用了基于水文的方法（在DRAINMOD模型中采用了这种方法）来预测雨水利用,同时考虑了影响雨水利用的大多数田间条件和管理实践。（在适当考虑到许多对雨水流动有直接/间接影响的现场条件和管理实践的情况下,这些方法的不足;从而导致CROPWAT产生不正确的IRs估计）:本文的研究结果表明,由于预测的长江流域下游水稻种植区气候变化,未来农业生产力和水资源保护都将面临严重威胁。利用水文模型分析农田水文过程变化时,必须确保水文模型和作物模型（无论是在其输入模块还是计算序列中）考虑到研究地区普遍存在的田间条件和管理做法。模拟模型的局限性,如对部分参数确定的方法误差,将导致不准确的模拟结果,从而削弱农业、环境和水资源管理的效果。因此,本文对于模型在模拟农田水分平衡和灌溉需求方面的改进将有助于更好地了解农田水文,更好地利用现有水资源,从而提高农业生产效率。