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Deep neural network algorithm for estimating maize biomass based on simulated Sentinel 2A vegetation indices and leaf area index

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The Crop Journal 2020年第1期8卷 87-97页

作者： Xiuliang Jin Zhenhai li Haikuan Feng Zhibin Ren shaokun li Institute of Crop Sciences Chinese Academy of Agricultural SciencesKey Laboratory of Crop Physiology and EcologyMinistry of AgricultureBeijing 100081China Beijing Research Center for Information Technology in Agriculture Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102JilinChina

Accurate estimation of biomass is necessary for evaluating crop growth and predicting crop *** is also a key trait in increasing grain yield by crop *** aims of this study were(i)to identify the best vegetation indices for estimating maize biomass,(ii)to investigate the relationship between biomass and leaf area index(LAI)at several growth stages,and(iii)to evaluate a biomass model using measured vegetation indices or simulated vegetation indices of Sentinel 2A and LAI using a deep neural network(DNN)*** results showed that biomass was associated with all vegetation *** three-band water index(TBWI)was the best vegetation index for estimating biomass and the corresponding R2,RMSE,and RRMSE were 0.76,2.84 t ha−1,and 38.22%*** was highly correlated with biomass(R2=0.89,RMSE=2.27 t ha−1,and RRMSE=30.55%).Estimated biomass based on 15 hyperspectral vegetation indices was in a high agreement with measured biomass using the DNN algorithm(R2=0.83,RMSE=1.96 t ha−1,and RRMSE=26.43%).Biomass estimation accuracy was further increased when LAI was combined with the 15 vegetation indices(R2=0.91,RMSE=1.49 t ha−1,and RRMSE=20.05%).Relationships between the hyperspectral vegetation indices and biomass differed from relationships between simulated Sentinel 2A vegetation indices and *** estimation from the hyperspectral vegetation indices was more accurate than that from the simulated Sentinel 2A vegetation indices(R2=0.87,RMSE=1.84 t ha−1,and RRMSE=24.76%).The DNN algorithm was effective in improving the estimation accuracy of *** provides a guideline for estimating biomass of maize using remote sensing technology and the DNN algorithm in this region.

关键词： Biomass estimation Maize Vegetation indices Deep neural network algorithm LAI

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Comparison and analysis of maize grain commodity quality and mechanical harvest quality between China and the United States

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International Journal of Agricultural and Biological Engineering 2022年第1期15卷 55-61页

作者： Keru Wang Ruizhi Xie Jun Xue lirong Sun shaokun li Institute of Crop Sciences Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of AgricultureBeijing 100081China Tongliao Agricultural and livestock Product Quality and Safety Center Tongliao 028000Inner MongoliaChina

Maize is a bulk commodity in international agricultural product trading,and unified and standardized quality inspection standards are the basis of purchase and sales and other trading *** and the United States are the largest maize producers and consumers in the world,jointly accounting for more than 60%of the world's total *** this research,the used data were from annual maize harvest quality reports released by the *** Council in 2011-2019 and 2987 groups of mechanical grain harvest sample data collected by the Crop Cultivation and Physiology Innovation Team of the Chinese Academy of Agricultural Sciences in 2012-2019,this study compares the quality standards of commercial maize grain in China and the United States,the mechanical harvest quality(which affects the quality of the maize grain commodity),and the status quo of harvesting and storage processes in the two ***,this study analyzes the differences in the formulation of mechanical harvest quality standards between China and the United States,as well as the reasons behind these differences,and recommends requirements for the formulation of quality standards for maize production technology and commodities that are in line with the economic conditions and maize-production conditions in China and in line with international standards in order to provide support for the industrialization of modern maize production in China.

关键词： maize quality standard mechanical grain harvesting test method

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In-field harvest loss of mechanically-harvested maize grain and affecting factors in China

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International Journal of Agricultural and Biological Engineering 2021年第1期14卷 29-37页

作者： liangyu Hou Keru Wang Yizhou Wang Lulu li Bo Ming Ruizhi Xie shaokun li The Key Laboratory of Oasis Eco-Agriculture Xinjiang Production and Construction Corps/Agricultural CollegeShihezi UniversityShihezi 832000XinjiangChina Institute of Crop Sciences Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081China

Field harvest loss is a common problem of maize grain mechanical harvesting in China and *** 2012 to 2019,2987 groups of samples for the quality of mechanical grain harvesting in field were obtained in 21 major maize-producing provinces,cities,and regions of *** analysis performed in this study showed that the average harvest loss of fallen ears was equivalent to 76.5%of the total harvest loss,indicating that the harvest loss in the mechanical harvesting of maize grain mainly came from the loss of fallen ***,statistical analysis of the harvest loss in different ranges of grain moisture contents showed that,when the grain moisture content fell below 20%,the harvest loss rate of fallen ears and the total harvest loss rate both increased sharply,and the harvest loss of fallen ears increased faster than the harvest loss of fallen grain with a decreasing grain moisture ***,the results of multi-point experiments and harvest experiments in different periods showed that,during harvesting time,the harvest loss of fallen ears caused by lodging was the main reason for in-field harvest losses in the mechanical harvesting of maize *** from the above mentioned,the test results of 35 groups of harvesters for the in-field mechanical harvesting of maize grain showed that the harvester types and their operating parameters were important factors affecting the harvest loss in the mechanical harvesting of maize ***,the principal paths to reduce harvest loss in the mechanical harvesting of maize grain are to breed lodging-resistant maize varieties,adopt reasonable planting densities,cultivate healthy plants,develop harvesters with low harvesting loss,intensify the training of operators,and harvest at an appropriate time.

关键词： maize grain mechanical harvest harvest losses affecting factors fallen ears fallen grain

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Review of combine harvester losses for maize and influencing factors

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International Journal of Agricultural and Biological Engineering 2021年第1期14卷 1-10页

作者： Keru Wang Ruizhi Xie Bo Ming Peng Hou Jun Xue shaokun li Institute of Crop Sciences Chinese Academy of Agricultural SciencesKey Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081China

The high harvest losses associated with the mechanical harvesting of maize in China are currently a major barrier to the adoption of this *** paper summarizes works of literature regarding harvest losses from the combine harvesting of maize in China and *** main findings are as follows:(1)In 2012-2019,2987 samples data obtained from the major maize production areas of China showed that the average harvest loss was 345.2 kg/hm2(3.5%of the average yield),with losses ranging from 0 to 9288.5 kg/hm2;(2)The harvest losses from combine harvesting are mainly caused by the dropping of *** ear losses include the pre-harvest loss caused by ear abscission,damage caused by maize borer,lodging,and the ear loss during combine harvesting,and the main pre-harvest loss is caused by lodging;(3)Harvest losses are affected by maize variety,planting mode,cultivation management,pests and diseases,weather conditions during harvesting,harvest date,combine harvester type,harvester adjustment,operator proficiency,and the terrain conditions of the maize field;(4)The harvest losses from combine harvesting are also related to the type of header,feeding and threshing methods,the adjustment of header stripping clearance,feeding amount,forward speed,cylinder or rotor speed,and the clearance between the cylinder and the concave of the ***,the combine losses mainly come from header *** order to reduce the harvest losses,the following solutions were proposed:(1)Breed and select maize varieties which are resistant to lodging,especially during the field drying of mature grains,as well as those resistant to maize borer and stalk rot;(2)Select varieties suitable for grain harvest-which requires matching the accumulated-temperature demand of the maize hybrids,optimal plant density,row spacing,and irrigation and fertilizer management with the light and heat conditions of the production area while cultivating uniform populations and healthy plants-as well as preve

关键词： maize grain combine harvest ear dropping kernel dropping harvest loss influence factors

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Device for determining critical wind speed of stalk breaking to evaluate maize lodging resistance

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International Journal of Agricultural and Biological Engineering 2020年第5期13卷 1-7页

作者： Jun Xue Bo Ming Keru Wang Ruizhi Xie Peng Hou shaokun li Institute of Crop Sciences Chinese Academy of Agricultural SciencesKey Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081China

The accurate evaluation of the lodging resistance of maize plants can provide a basis for the breeding of lodging-resistant cultivars and the regulation of cultivation ***,the traditional methods for evaluating maize lodging resistance in terms of plant morphology and stalk mechanical strength have certain *** objective of this research was to develop a device for determining the critical wind speed of maize stalk *** device was equipped with a centrifugal fan to supply airflow and was powered by a frequency conversion *** frequency converter adjusted the motor speed and thus adjusted the wind *** wind speed decreased first and then increased with increasing height above the outlet of the device,and maximum wind speed can reach 40 m/*** device was convenient for transportation in the field,has a low cost,and can quickly,accurately,and objectively determine the lodging *** tests showed that the device ran stably for a long *** coefficient of variation of three repeated measurements was between 1.5%and 4.8%for four maize *** new device can measure the critical wind speed of maize lodging and identify the lodging resistance for different maize cultivars,cultivation practices,and plant health conditions,and can thus overcome barriers to measuring the maize lodging resistance under natural wind conditions.

关键词： maize stalk lodging critical wind speed turbofan measuring device wind pressure

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Analysis of factors affecting the impurity rate of mechanically-harvested maize grain in China

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International Journal of Agricultural and Biological Engineering 2020年第5期13卷 17-22页

作者： Zhaofu Huang Jun Xue Bo Ming Keru Wang Ruizhi Xie Peng Hou shaokun li Institute of Crop Sciences Chinese Academy of Agricultural SciencesKey Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing100081China

The grain impurity rate is an important index for assessing the quality of mechanical maize ***,it is of great significance to clarify the current situation of maize impurity rate and study the factors that affect the impurity rate in order to promote the development of mechanical maize harvesting *** 2012 to 2019,a total of 2504 maize impurity rate measurements were *** results showed that the average impurity rate at maize harvest was 1.18%in China,in which the Huang-Huai-Hai summer maize area was 1.68%,which was significantly higher than the 0.65%in the Northwest spring maize area and 0.77%in the North China spring maize *** was a significant positive correlation between the impurity rate and the moisture content of the maize *** average moisture content of maize at harvest in Huang-Huai-Hai summer maize area was the highest at 27.55%,which was the main reason for the high impurity rate in this *** harvesting different varieties with the same moisture content,there were significant differences in the impurity rate between different *** cob hardness of the variety may also affect the impurity rate of *** harvesters and weather conditions during harvesting are also important factors affecting the impurity ***,by breeding fast dehydrated varieties and harvesting maize in time,the impurity rate of maize during mechanical harvesting can be effectively reduced.

关键词： mechanically-harvested maize grain impurity rate factors analysis

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Influence of plastic film mulching and planting density on yield,leaf anatomy,and root characteristics of maize on the Loess Plateau

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The Crop Journal 2020年第4期8卷 548-564页

作者： li Niu Yanyan Yan Peng Hou Wenbo Bai Rulang Zhao Yonghong Wang shaokun li Taisheng Du Ming Zhao Jiqing Song Wenbin Zhou Key Laboratory of Prevention and Control of Residual Pollution in Agricultural Film Ministry of Agriculture and Rural AffairsInstitute of Environment and Sustainable Development in AgricultureChinese Academy of Agricultural SciencesBeijing 100081China College of Water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081China Ningxia Academy of Agriculture and Forestry Sciences Crops Research InstituteYongning 750105NingxiaChina

In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth *** film mulching is commonly used to increase maize yield in this area,because it increases topsoil temperature and moisture content as well as water use ***,the physiological and anatomical bases of maize yield improvement with plastic film mulching are not well *** effects of plastic film mulching and planting density on maize yield,photosynthetic characteristics,respiration,leaf anatomy,and root growth were studied in a two-year field experiment conducted on the Loess Plateau of China in 2017 and *** experiment used a split-split plot design with two mulching treatments(plastic film mulching and no mulching),two planting densities(7.5×104 and10.5×104 plants ha-1),and two maize cultivars,Zhengdan 958 and Xianyu *** with no mulching,plastic film mulching increased maize yields by 31.1%–46.4%in 2017 and3.6%–34.7%in *** with low planting density,high planting density significantly increased and slightly reduced yields of both cultivars in the dry year 2017 and the rainy year 2018,*** film mulching increased photosynthesis and respiration as well as leaf stomatal density and *** rate,dark respiration,and stomatal conductance and aperture were lower at high planting than at low planting *** yield was positively correlated with photosynthesis,dark respiration,and stomatal *** increased root dry weight and length in the 0–20 cm soil layer and root activity at ***,the changes in root growth and leaf anatomy resulted in increased photosynthesis and dark respiration,and the increased photosynthesis contributed to the increase in grain yield and biomass production under plastic film mulching *** results increase understanding of the physiological mechanisms by which plas

关键词： planting cultivar anatomy

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Improving harvest efficiency of maize varieties via accumulated temperature in a certain planting area

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International Journal of Agricultural and Biological Engineering 2021年第4期14卷 175-181页

作者： Zhaofu Huang liangyu Hou Jun Xue Keru Wang Ruizhi Xie Peng Hou Bo Ming shaokun li Institute of Crop Sciences Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081China

The ripening and drying of maize(Zea mays L.)grain are closely related to *** accordance with maize grain drying characteristics,regional accumulated temperature(AT0≥0℃)distribution is of great significance for a rational allocation of maize varieties,thus reducing grain moisture content(MC)to improve maize harvest *** 2016 to 2018,a multi-site trial was carried out in the spring maize production area of Northeastern *** this study,under a guaranteed rate of 80%for AT0,this area was divided into 15 accumulated temperature zones(ATZs)with an interval of 100℃ based on climatic data of 78 local weather *** the AT0 demand of different maize varieties during different growth stages was calculated by combining experimental records with the established prediction model of MC,and then,the spatial partition for different types of maize varieties under different MCs was *** results showed that all the tested varieties could not reach physiological maturity(PM)at ATZs 13-15,hence,where maize planting is *** the increasing accumulated temperature demand of different types of maize varieties from planting to PM,to the MC of 25%and to the MC of 20%,the unplantable areas were gradually expanded from south to north while the region where the maize varieties could be harvested under different MCs was also moved ***,at 1-2 ATZs,it is entirely possible to achieve mechanical kernel harvesting under the MC of 20%,even though the AT0 requirements of the varieties are relatively ***,on the grounds of AT0 demand law of maize varieties and heat resource distribution in Northeastern China,the layout optimization for achieving different harvesting scenarios is conducive to providing a basis not only for selecting suitable varieties but also for promoting mechanical kernel harvesting in the spring maize production area of this region.

关键词： grain moisture content accumulated temperature zone cultivars’layout Northeastern China

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Evaluation of grain breakage sensitivity of maize varieties mechanically-harvested by combine harvester

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International Journal of Agricultural and Biological Engineering 2020年第5期13卷 8-16页

作者： Yizhou Wang Lulu li Shang Gao Yanan Guo Guoqiang Zhang Bo Ming Ruizhi Xie Jun Xue Peng Hou Keru Wang shaokun li Institute of Crop Sciences Chinese Academy of Agricultural SciencesKey Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081China

A high grain breakage rate is the main problem that occurs during mechanical maize harvest in *** breakage sensitivity of different varieties was significantly different,and the breakage resistance is ***,breakage resistant variety screening can help improve the field production efficiency and provide references for breeding *** this study,42 varieties of maize were harvested with the same mechanical parameters and the same manipulator on a range of harvest dates at experimental stations in Xinxiang,Henan Province,in 2017 and Changji,Xinjiang Province,in 2018 to determine the sensitivity of grain moisture content on grain breakage rate during machine harvest for different *** integral value of the grain breakage rate curve corresponding to the range of 15%to 30%grain moisture content was used as an index that expressed the sensitivity of maize grains to breakage depending on grain moisture content(BSW).Forty-two varieties were categorized as having weak,intermediate,or strong *** the same four varieties in the two stations,lianchuang 825 and lianchuang 808 were classified as sensitive and fragile varieties,Shandan 650 was classified as an intermediate variety,Zeyu 8911 was divided into weak sensitive and breakage-resistance varieties in Xinxiang and intermediate varieties in *** BSW classification results at the two experimental sites were generally consistent,indicating that breakage sensitivity due to moisture content may be a relatively stable genetic *** study suggested that the integral method for determining BSW can be used to assess the resistance of different maize varieties to grain breakage during mechanical *** integral method was used to identify twelve breakage-resistant varieties in Xinxiang Station,and six breakage-resistant varieties in Changji *** study provides a method for screening maize varieties that are suited to mechanical grain harvesting and for studying t

关键词： maize mechanical grain harvest breakage resistance integral method varieties classification

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Allocation of maize varieties according to temperature for use in mechanical kernel harvesting in Ningxia, China

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International Journal of Agricultural and Biological Engineering 2021年第1期14卷 20-28页

作者： Hongyan li Yonghong Wang Jun Xue Ruizhi Xie Keru Wang Rulang Zhao Wanmao liu Bo Ming Peng Hou Zhentao Zhang Wenjie Zhang shaokun li Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081China Key Laboratory of Crop Physiology and Ecology Ministry of Agriculture and Rural AffairsBeijing 100081China Crop Research Institute of Ningxia Academy of Agriculture and Forestry Sciences Yinchuan 750105China

The reasonable assessment of maize varieties in different ecological regions can allow temperature resources to be fully exploited and reach the goal of high yield and efficiency and is thus an important direction of modern maize development in *** this study,a logistic power nonlinear growth model was used to simulate the accumulated temperature required for kernel dehydration to moisture contents of 25%,20%,and 16%for various maize cultivar,which were divided into six types based on the accumulated temperature required for kernel dehydration to a moisture content of 25%.The relationship between the yield of maize cultivars and the accumulated temperature required for kernel dehydration to a moisture content of 25%was found to follow a unary function *** the planted maize variety was found to increase economic returns by more than 7000 RMB/hm2 in Ningxia,Northwest *** the conditions of mechanical grain harvesting,economic benefits can be further increased by means of selecting high yields and fast-dehydrating varieties,selling when the grain dehydration is below 16%.A better way to achieve grain dehydration to a moisture content below 16%is to postpone the harvest date as much as possible rather than drying after the harvest at physiological *** areas of various types of maize varieties can be dehydrated to moisture contents of 25%,20%,and 16%were *** on the distribution of heat resources in different regions of Ningxia from the normal sowing date to October 31 before winter irrigation,the appropriate cultivars for various regions in the province were determined based on production ***,in different areas of Ningxia,selecting suitable maize varieties according to temperature resources can reach a high yield and mechanical kernel harvesting,and ultimately obtain higher economic benefits.

关键词： maize dehydration grain yield economic return mechanical kernel harvesting

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