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Estimation of Sunflower Seed Yield Using Partial Least Squares Regression and Artificial Neural Network Models

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Pedosphere 2018年第5期28卷 764-774页

作者： zeng wenzhi XU Chi Gang ZHAO WU Jingwei HUANG Jiesheng State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University (China) Crop Science Group Institute of Crop Science and Resource Conservation University of Bonn Katzenburgweg 5 Bonn 53115(Germany)

Statistical models can efficiently establish the relationships between crop growth and environmental conditions while explicitly quantifying uncertainties. This study aimed to test the efficiency of statistical models established using partial least squares regression(PLSR) and artificial neural network(ANN) in predicting seed yields of sunflower(Helianthus annuus). Two-year field trial data on sunflower growth under different salinity levels and nitrogen(N) application rates in the Yichang Experimental Station in Hetao Irrigation District, Inner Mongolia, China, were used to calibrate and validate the statistical models. The variable importance in projection score was calculated in order to select the sensitive crop indices for seed yield prediction. We found that when the most sensitive indices were used as inputs for seed yield estimation, the PLSR could attain a comparable accuracy(root mean square error(RMSE) = 0.93 t ha-1, coefficient of determination(R^2) = 0.69) to that when using all measured indices(RMSE = 0.81 t ha-1,R^2= 0.77). The ANN model outperformed the PLSR for yield prediction with different combinations of inputs of both microplots and field data. The results indicated that sunflower seed yield could be reasonably estimated by using a small number of crop characteristic indices under complex environmental conditions and management options(e.g., saline soils and N application). Since leaf area index and plant height were found to be the most sensitive crop indices for sunflower seed yield prediction, remotely sensed data and the ANN model may be joined for regional crop yield simulation.

关键词： leaf area index microplot experiment plant height remote sensing salinization variable importance in projection score

Sensitivity analysis of the SWAP(Soil-Water-Atmosphere-Plant)model under different nitrogen applications and root distributions in saline soils

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Pedosphere 2021年第5期31卷 807-821页

作者： Guoqing LEI wenzhi zeng Yonghua JIANG Chang AO Jingwei WU Jiesheng HUANG State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072(China) School of Remote Sensing and Information Engineering Wuhan UniversityWuhan 430079(China) State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079(China)

Sensitivity analysis is important for determining the parameters in the model calibration *** our study,a variance-based global sensitivity analysis(extended Fourier amplitude sensitivity test,EFAST)was applied to an agro-hydrological model(the SWAP(Soil-Water-Atmosphere-Plant model)model).The sensitivities of 20 parameters belonging to 4 categories(soil hydraulics,solute transport,root water uptake,and environmental stresses)for the simulated accumulated transpiration,dry matter(DM),and yield of sunflowers were analyzed under three nitrogen application rates(N1,N2,and N3),four salinity levels(S1,S2,S3,and S4),and three root distributions(R1,R2,and R3).The results indicated that for predominantly loamy soils,the high-impact parameters for accumulated transpiration,DM,and yield were the soil hydraulic parameters(αand n),critical stress index for compensatory root water uptake(ωc),the salt level at which salt stress starts(Pi),the decline of root water uptake above Pi(SSF),residual water content(θr),saturated water content(θs),and relative uptake of solutes by roots(TSCF).We also found that nitrogen application did not change the order of the parameter impacts on accumulated transpiration,DM,and ***,TSCF replacedαas the highest-impact parameter for the accumulated transpiration,DM,and yield at high salinity levels(S2 and S3).Furthermore,αwas also the highest-impact parameter for DM and yield under different root distributions,but the highest-impact parameters for transpiration wereωc,α,andθs under R1,R2,and R3,*** application could be neglected when considering the interactive effects of nitrogen application,salinity level,and root distribution on the transpiration,DM,and ***,the mean values and uncertainties of the transpiration,DM,and yield were similar in all scenarios,except S3,which showed a sharp decrease in the mean *** suggest determining the above eight parameters(α,n,ωc,Pi,SSF,θr,θs,and TSCF)and the sat

关键词： accumulated transpiration agro-hydrological model dry matter hydraulic parameter sunflower yield

Cotton flooding and drought analysis regarding growth stages in Hubei,China,using a daily agrometeorological index

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International Journal of Agricultural and Biological Engineering 2023年第4期16卷 173-183页

作者： Long Qian Cheng Chen Xiaohong Chen wenzhi zeng Yawen Gao Kenan Deng School of Civil Engineering Sun Yat-sen UniversityGuangzhou 510275China State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminatsy Shanghai 200233China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China

Cotton yield is restricted worldwide by flooding and drought that occur across various growth *** this study,cotton flooding and drought in Hubei(a major cotton-production province in China)from 1961 to 2019 were analyzed regarding growth stages through a daily index named the standardized antecedent precipitation evapotranspiration index(SAPEI).In addition,the impacts of flooding and drought on cotton climatic yield were quantified using multiple regression *** results showed that the temporal trends of cotton flooding and drought intensities were generally smooth,except for an obvious downward trend for cotton drought intensity at the flowering and boll-forming ***,cotton drought intensity varied more drastically than that of flooding over the ***-flooding proneness was much greater than cotton-drought proneness at all growth stages,and the most flooding-prone and drought-prone periods were identified as the flowering and boll-forming stage and the budding stage,*** terms of spatial distribution,northeastern Hubei and southwestern Hubei were most prone to flooding and drought,*** SAPEI-based regression model(R2=0.490,p<0.001),obviously outperforming the SPEI-based model(R2=0.278,p<0.05),revealed that both cotton flooding and drought exhibited negatively significant effects on cotton climatic yield and that the yield-reducing effect of cotton flooding was much greater than that of ***,when growth stages were further considered using regression analysis,only the flowering and boll-forming stage was detected with a significant yield-reducing effect of cotton *** conclusion,the SAPEI can effectively assist in monitoring cotton flooding and drought;cotton flooding,especially during the flowering and boll-forming stage and that occurring in northeastern Hubei,is the key issue for cotton field water management in Hubei.

关键词： irrigation drainage climatic yield waterlogging

Decline in tree-ring growth of Picea mongolica and its intra-annual eco-physiological responses to drought and CO_(2) enrichment in semi-arid China

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Journal of Forestry Research 2024年第4期35卷 89-101页

作者： Xiaomin zeng Ping Ni Xiaohong Liu wenzhi Wang Yao Li Wenchao Wang School of Geography and Tourism Shaanxi Normal UniversityXi’an 710119People’s Republic of China The Key Laboratory of Mountain Environment Evolution and Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041People’s Republic of China CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid ***,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains *** this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent *** results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since ***-ever,the decreasing trend of earlywood BAI_(res) was higher than that of *** response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,***_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly *** stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing *** study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.

关键词： Tree growth Drought Water-use efficiency Seasonal differences Stable isotopes

基于高光谱与协同克里金的土壤耕作层含水率反演

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农业工程学报 2014年第13期30卷 94-103页

作者：徐驰曾文治黄介生伍靖伟武汉大学水资源与水电工程科学国家重点实验室武汉430072

为研究土壤耕作层（0-40 cm）含水率的空间分布情况,利用EO-1的Hyperion传感器高光谱数据,对研究区域（106°20′-109°19′E,40°19′-41°18′N）的表层（0-10 cm）含水率进行定量反演,并利用表层含水率反演结果作为协同克里金插值的... 详细信息

为研究土壤耕作层（0-40 cm）含水率的空间分布情况,利用EO-1的Hyperion传感器高光谱数据,对研究区域（106°20′-109°19′E,40°19′-41°18′N）的表层（0-10 cm）含水率进行定量反演,并利用表层含水率反演结果作为协同克里金插值的协变量,同时利用103个采样点实测的耕作层含水率作为主变量,进行协同克里金插值。结果表明：通过特征指数法提取水分反演的敏感波段集中在1 295-2 224 nm波长区间,特征指数法模型校正的相关系数r〉0.5但模型验证的精度较低（r〈0.2）;通过偏最小二乘法建模,模型校正的r〉0.8,模型验证的r〉0.5,效果较好;运用协同克里金插值时,将反演的表层含水率作为协变量,可以弥补主变量耕作层含水率样本点少,变异函数欠稳定的缺点,同时,所提取理论模型的块金值（C0）与基台值（C0＋C）的比值均〈25%,随机因素比例小,模型稳健。此外,协同克里金插值方法与利用表层与耕作层含水率线性拟合进行预测相比,能够有效提高预测精度,决定系数r2和Nash效率系数（nash-sutcliffe modelling efficiency,NSE）分别提高72.6%和89.9%,因此,将高光谱反演与协同克里金方法相结合,可以综合两者优势,节约采样成本,提高预测效率。

关键词：土壤含水率遥感高光谱定量反演协同克里金插值

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概率2-赋范线性空间

贵州大学学报(自然科学版) 1985年第1期 13-21页

作者：曾文智

§1 引言概率度量空间(PM 空间)是1942年 Menger[1]首先提出,它是用一个分布函数表示任意两点间距离的空间,由于在许多情况下,集合中两元间距离具有随机性,这时用概率度量(即用一个分布函数表示距离)更符合客观实际,因此研究 PM 空间具... 详细信息

§1 引言概率度量空间(PM 空间)是1942年 Menger[1]首先提出,它是用一个分布函数表示任意两点间距离的空间,由于在许多情况下,集合中两元间距离具有随机性,这时用概率度量(即用一个分布函数表示距离)更符合客观实际,因此研究 PM 空间具有重要

关键词：赋范线性空间定义定理有界赋范向量空间概率不动点固定点点(数学)

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土壤盐分与施氮量交互作用对葵花生长的影响

农业工程学报 2014年第3期30卷 86-94页

作者：曾文治徐驰黄介生伍靖伟高真武汉大学水资源与水电工程科学国家重点实验室武汉430072

为了研究盐分和氮素交互作用对葵花生长的影响，采用双因素随机区组设计在内蒙古河套灌区义长试验站开展微区试验，观测指标包括葵花的出苗率、成熟期株高、叶面积、地上部分干物质量、吸氮量和产量等。试验结果表明土壤0～20cm初始盐... 详细信息

为了研究盐分和氮素交互作用对葵花生长的影响，采用双因素随机区组设计在内蒙古河套灌区义长试验站开展微区试验，观测指标包括葵花的出苗率、成熟期株高、叶面积、地上部分干物质量、吸氮量和产量等。试验结果表明土壤0～20cm初始盐分质量分数是影响葵花生长的主要限制因素，将土壤0～20cm初始盐分质量分数由〈0．25％（S）增加至1％以上（S4）能够使不同施氮水平下葵花出苗率、株高、叶面积、干物质量和产量的均值分别降低72．O％、40．0％、58．5％、41．7％和76．41％，并且在不同的施氮量水平下，葵花的出苗率均与土壤0～20cm初始盐分质量分数呈线性下降的关系。当土壤盐分水平为〉0．5％～1．0％（S3）时，将施氮量水平由Ⅳ1（90kg／hm2）增加至N3（180kg／hm^2）能够使葵花出苗率、株高、叶面积、干物质量和产量分别增加16．7％、35．6％、39．1％、69．9％和80．0％；当土壤盐分水平大于1．0％（＆）时，将施氮量水平由Ⅳ1增加至M能够使上述5项指标分别增加45．4％、20．5％、47．4％、42．7％和76．2％。但是当土壤初始盐分质量分数小于0．5％时，增施氮肥对上述5项指标的影响效果降低。此外，尽管葵花的吸氮量随氮肥施入量的增加而增加，但是葵花对氮肥的利用效率还与受到土壤盐分水平的影响，当土壤0～20cm初始盐分质量分数小于0．5％时，葵花对氮肥的利用率随施氮量的增加而降低，而当土壤0～20cm初始盐分质量分数大于0．5％时，增施氮肥有助于提高葵花对氮肥的利用率。综合考虑收益、环境影响以及农业灌溉措施的等因素，建议适合河套灌区的合理施氮水平为135kg／hm2。

关键词：土壤盐分灌溉交互作用施氮量

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外包土工布暗管排盐条件下水盐运移规律

农业工程学报 2020年第2期36卷 130-139页

作者：陈名媛黄介生曾文治敖畅刘丹刘义武汉大学水利水电学院武汉430072

为揭示外包土工布暗管埋设在非饱和带时淋洗后水分和盐分的运移规律,该文设计了模拟暗管排水的室内试验,研究2种土壤初始状态下(非饱和状态和田持状态),排水初期暗管与地下水位的相对位置及其排水排盐情况,从开始淋洗至暗管停止排水全... 详细信息

为揭示外包土工布暗管埋设在非饱和带时淋洗后水分和盐分的运移规律,该文设计了模拟暗管排水的室内试验,研究2种土壤初始状态下(非饱和状态和田持状态),排水初期暗管与地下水位的相对位置及其排水排盐情况,从开始淋洗至暗管停止排水全过程中地下水埋深及含盐量变化规律、暗管的排水排盐效果及土壤剖面的水盐动态运移规律。结果表明:在暗管周围包裹土工布的情况下,土壤初始状态无论是非饱和还是田持,当暗管开始排水时地下水均已完全淹没暗管,此时的排盐量最大,流量呈先增大后减小的变化趋势,且地下水位先升高后降低,地下水含盐量随着淋洗水量的增加由累积转变为脱盐。对比淋洗非饱和土壤(试验1)和淋洗田持土壤(试验2)的试验结果,试验2中暗管的排水、排盐效果优于试验1,在试验1中淋洗非饱和土壤时,土壤脱盐率在垂直方向上随土壤深度的增加逐渐降低,0~20 cm土层的脱盐率(>85%)最大,降至无盐水平,暗管周围土壤脱盐率相对较小(60%)。此外,试验1中淋洗脱盐效果大于暗管排盐效果,暗管主要排出暗管以上土壤盐分;试验2中暗管排盐效果增强,暗管不仅排出暗管周围土壤盐分,而且排出暗管以下土层及地下水中盐分,随着淋洗水量的增加,土壤由脱盐型转变为排盐型。研究结果表明外包土工布暗管的应用效果受地下水与暗管相对位置的影响,合理提高淋洗水量可以增强暗管排水排盐效果及土壤脱盐效果,有效改善土壤盐渍化。研究结果可为西北内陆干旱地区不同地下水埋深条件下暗管排盐技术的推广和应用提供理论支撑和科学指导。

关键词：暗管排水盐分脱盐率排水率排盐率地下水埋深

波导层介质对二维光子晶体反射光谱的影响(英文)

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红外与激光工程 2014年第6期43卷 1873-1877页

作者：童凯谷朝聪曾文智王会波卢建如燕山大学电气工程学院 92635部队

构建了基底介质为SiO2、表面覆层介质为TiO2的二维光子晶体,采用严格耦合波法分析了二维光子晶体的窄带光学传输特性。分析了二维光子晶体的晶格周期、波导层的折射率及厚度对其反射光谱的影响。分析结果表明:当光子晶体的晶格周期和波... 详细信息

构建了基底介质为SiO2、表面覆层介质为TiO2的二维光子晶体,采用严格耦合波法分析了二维光子晶体的窄带光学传输特性。分析了二维光子晶体的晶格周期、波导层的折射率及厚度对其反射光谱的影响。分析结果表明:当光子晶体的晶格周期和波导层介质厚度为常数时,随着波导层介质折射率的增大,光子晶体的反射峰值波长红移,且波导层折射率与反射峰值波长呈线性关系。当光子晶体波导层介质折射率为常数时,波导层厚度增大或光子晶体晶格周期的增大都会引起光子晶体反射峰值波长增大,但这两个参数与反射峰值波长只是在一定的变化范围内为线性关系。此种结构的二维光子晶体覆层表面吸附分布不均匀的介质时,通过分析光子晶体的呈现光谱可获得其表面吸附介质的不均匀特性。

关键词：光子晶体严格耦合波峰值波长波导层