Can harvest outsourcing services reduce field harvest losses of rice in China?

The purpose of this study is to quantify the rice harvest losses in China and to evaluate the impacts of machinery and harvest outsourcing services on these losses,given the background of high-speed mechanization and outsourcing services.Data were collected from a national survey conducted in 2016 by the research team in conjunction with the Research Center for the Rural Economy of the Ministry of Agriculture and Rural Affairs of China.A non-parametric method was used to test whether combine harvesting and outsourcing services could significantly reduce harvest losses.Next,quantile regression was used to estimate the real effects of machinery and outsourcing services on harvest losses.The analysis yielded four main study outcomes.First,the harvest loss rate of rice in China was 3.65%.Second,mechanical reaping and winnowing caused greater losses than manual methods,while the opposite was true of field transportation.Third,combine harvesting increased the losses.Fourth,the effects of an outsourcing service on losses differed among the different harvesting methods.Outsourcing services increased losses in segmented harvesting but they reduced losses in combine harvesting.

Assessment of BRRI Whole Feed Combine Harvester (Model BRRI WCH2021) for Mechanized Rice Harvesting in Bangladesh

Agricultural mechanization plays a pivotal role in the transition from subsistence to commercial agriculture, with a particular focus on labour-intensive activities like harvesting. This study assesses the operational characteristics of the BRRI Whole Feed Combine Harvester (Model BRRI WCH2021) at the field level. Developed under the SFMRA project, the harvester’s technical performance and loss assessment were conducted during the Boro 2022 and Aman 2022 seasons in farmer fields in Bangladesh’s Rangpur region. The field efficiency of the harvester was determined to be 62.5% and 57.9% in the Boro and Aman seasons, respectively. Fuel consumption rates were recorded at 2.77 l/ha and 2.31 l/ha for the Boro and Aman seasons. The total harvesting losses, encompassing cutter bar, shatter, cylinder, and separation loss, averaged 0.56% and 0.48% in the Boro and Aman seasons, respectively. Mechanized harvesting with the BRRI Whole Feed Combine Harvester significantly reduced paddy losses by 5.81% compared to manual methods. The field evaluation results indicate the combine harvester’s satisfactory performance, highlighting its potential to alleviate labour demands during peak harvesting. The development of the BRRI WCH offers a sustainable solution for rice harvesting mechanization among progressive farmers. It paves the way for the broader adoption of advanced agricultural technology in Bangladesh.

Experimental study on lodged corn harvest loss of small harvesters

The harvesting difficulty caused by corn lodging aggravated the loss of grain,especially in the regions where small harvesters were used as the main force for corn harvesting.An experimental study and analysis of harvest loss of small harvesters on the root lodged corn were made to get the laws of lodged corn harvest loss.The experiment was conducted in different harvesting directions and at a range of harvesting speeds.A 4-row self-propelled corn harvester(JM-4Y),a 2-row crawler type self-propelled corn harvester(JM-2C),and a 2-row crawler-type corn harvester equipped with a spiral auxiliary feeding device for lodged stalks(JM-2CAF)were taken as the research objects and the grain loss per square meter and the ear loss quantity per 30 square meters were taken as the experiment indices.The results showed that the average grain loss masses of the JM-4Y harvester,the JM-2C harvester and the JM-2CAF harvester in different harvesting directions were 101.88g,285.72 g and 110.20 g,while the average corn ear losses were 10.08,33.54 and 9.28 pieces.The lowest harvest loss of the JM-4Y harvester appeared when the harvesting was the same as the lodging direction,while the JM-2CAF harvester caused the lowest harvest loss when the harvesting direction was opposite to the lodging direction.The different feeding demands of the ordinary harvester head and the auxiliary feeding devices made the harvesters have different feeding conditions.At different harvesting speeds,the average grain loss mass of the JM-4Y harvester,the JM-2C harvester and the JM-2CAF harvester were 139.06 g,453.42 g and 236.64 g while the average corn ear loss quantities were 15.12,52.52 and 34.80 pieces.The JM-4Y harvester had the lowest harvest loss at almost every harvesting speed,and the JM-2CAF harvester only had lower harvest loss when the harvesting speed was lower than 0.8 m/s.The insufficient time to lift and deliver the lodged stalk and the impact between the spiral blades and the stalks were the causes of harvest loss when harvesting speed got higher.This study provides practical and theoretical references for the loss reduction of lodged corn harvesting.

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

Field harvest loss is a common problem of maize grain mechanical harvesting in China and abroad.From 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 China.The 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 ears.Meanwhile,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 content.Moreover,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 grain.Apart 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 grain.Therefore,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.

Mechanical Harvesting Effects on Seed Yield Loss,Quality Traits and Profitability of Winter Oilseed Rape (Brassica napus L.)

China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 （Brassica napus L.） was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C （CHA, CHB, and CHC） were designed and manual harvesting （MH） as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting （MS/CH） showed an input/output ratio of 1：1.6, and it was 1：1.2 in mechanical sowing/manual harvesting （MS/MH）. Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.

Effects of harvesting method and date on yield loss and seed quality of rapeseed

China is one of the major rapeseed production countries in the world,but harvesting mechanization was still backward,and high harvest loss was a key inhibiting factor for rapeseed production.To obtain optimum harvesting date for winter rape in the Yangtze River Valley of China,artificial simulated combine harvesting and artificial two-stage harvesting were adopted to find correlations between harvesting date,rape variety,seed oil content,protein content,grain moisture rate,rapeseed straw moisture content,rapeseed unthreshing rate,grain drop loss rate,thousand seeds weight(TSW),and harvesting economic coefficient(HEC).Analysis of variance showed that rapeseed oil content,protein content and TSW were correlated with rape variety;HEC was correlated with harvesting method and rape variety.Rape variety was the dominant factor of rapeseed oil content,protein content,TSW and HEC.Grain moisture rate,un-threshing rate,grain drop loss rate and straw moisture content were correlated with harvesting method and date.Harvesting date was the dominant factor of rapeseed moisture rate,un-threshing rate,grain drop loss rate and straw moisture rate.Single factor tests further proved that harvesting date had less impact on rapeseed oil content,protein content,TSW and HEC.It showed little correlation with rapeseed quality except grain moisture rate.The optimum harvesting date could be known by change in straw moisture content.The combined harvesting should be carried out during the grain moisture content of 15%-20%with TSW stabilized in the highest level.The twostage harvesting cutting should be carried out at the grain moisture content of 35%-40%.This research offered a reference to harvesting method and date for rape cultivated in the Yangtze River Valley.

Soil nutrient loss due to tuber crop harvesting and its environmental impact in the North China Plain

Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environmental impacts. In the North China Plain area, we measured the losses of soil organic carbon （SOC） and nitrogen as wel as phosphorus due to SLCH and assessed their relationship with soil particle size composition, agronomic practices and soil moisture content. Our results show that the losses by harvesting potato of SOC, total nitrogen （TN）, available nitrogen （AN）, available phosphorus （AP） and total phosphorus （TP） were 1.7, 1.8, 1.8, 15.9 and 14.1 times compared by harvesting sweet potato, respectively. The variation of SOC, N and P loss by SLCH are mainly explained by the variation of plant density （PD） （17–50%）, net mass of an individual tuber （Mcrop/p） （16–74%）, soil clay content （34–70%） and water content （19–46%）. Taking into account the current sewage treatment system and the ratio of the nutrients adhering to the tubers during transportation from the ifeld （NTRP/SP）, the loss of TN and TP by harvesting of potato and sweet potato in the North China Plain area amounts to 3% N and 20% P loads in the water bodies of this region. The fate of the exported N and P in the sewage treatment system ultimately controls the contribution of N and P to the polution of lakes and rivers. Our results suggest that a large amount of SLCH-induced soil nutrient export during transportation from the ifeld is a potential polutant source for agricultural water for vast planting areas of tuber crops in China, and should not be overlooked.

Influence of Post-Harvest Storage Technologies on Weight and Rate Losses and Sensory Profile of Cola Nuts (<i>Cola nitida</i>) Produced in Côte d’Ivoire

The conservation of cola nuts (Cola nitida) poses a real problem in C&ocirc;te d’Ivoire because of the post-harvest losses. The objective of this study was to evaluate the impact of post-harvest technologies on organoleptic and physical properties of cola nut during storage. A biopesticide, glucose syrup and biopesticide + glucose syrup were applied to fresh cola nuts before conditioning and kept at 28&deg;C for 6 weeks. Physicochemical and sensory analyses were performed to check the quality of the nuts during storage. The results showed that the biopesticide keep cola nuts better than the others methods with only 11.66% ± 3.04% and 13.66% ± 3.95% of loss rates for white and red cola nuts respectively. Cola nuts treated with bio-pesticide retain significantly their freshness with 62.00% ± 1.15% of moisture for white nuts and 64.00% ± 2.00% of moisture for red nuts compared to those treated with glucose syrup and bio-pesticide + glucose syrup (56.66% ± 1.15%). Cola nuts treated with biopesticide have a better acceptability compared to those subjected to others treatments. The use of biopesticide for the storage of cola nuts minimizes the losses and maintains the quality whatever the type of cola.

粮食产后服务体系建设的国际经验与启示

减少粮食损耗是实现可持续发展和保障粮食安全的重要途径,粮食产后服务体系建设是减少粮食损耗的关键环节。本文在分析中国粮食产后服务发展现状与问题的基础上,梳理了美国、加拿大、日本三个典型国家在发展粮食产后服务方面的一些经验和做法,并结合中国实际情况,探讨了其对中国粮食产后服务体系建设启示和镜鉴。研究结果表明,粮食产业链全商业化运作是美国和加拿大建设完备粮食产后服务体系的基石,先进的全产业链节粮减损技术及政府、企业与农户的合作协调机制是其粮食产后服务体系运行的关键;日本则在引进先进技术的同时,构建了政府、农协、农户三方合力建设的层次分明、规范运作的粮食产后服务体系,有效保障了农民种粮收益。本文据此进一步提出了完善中国粮食产后服务体系建设的对策思路。

基于PLC技术的联合收割机电气控制系统设计

以联合收割机电气控制系统为研究对象,利用可编程控制器(PLC)对联合收割机电气控制系统进行改进,以提高联合收割机运行效率和可靠性。通过对联合收割机的工作原理和液压作动系统进行分析,基于可编程控制器(PLC)进行联合收割机电气系统整体设计,并对电气系统的运行效果进行测试分析。试验结果表明:系统运行可靠,能够获得良好的收割效果,可将收割损失率控制在2%以内,验证了系统运行过程稳定性。

玉米联合收获机清选控制系统设计与试验

玉米联合收获机清选系统工况复杂,存在收获质量差、效率不高等问题。基于此,设计一套清选损失率控制为主同时兼顾含杂率的自动控制系统。首先分析以风机转速、振动筛转速和喂入量为影响因素,损失率、含杂率为评价指标的正交试验数据,获取影响损失率和含杂率的主次因素,提出清选系统自动控制策略;其次,为开展控制策略和算法的研究,建立清选系统中的风机转速、振动筛转速调节装置以及收获机纵向运动的数学模型,设计离散化PID控制算法。最后,基于MATLAB/dSPACE软硬件环境,搭建清选控制系统的硬件在环仿真平台,并进行控制器在环测试。试验证明:本文设定的双目标联合控制策略和控制算法,能够有效降低清选损失率、含杂率,其中清选损失率降到2.7%左右,含杂率为2.8%左右。

鲜食玉米收获机械发展阶段判定研究——基于收获效率与果穗损失视角

为促进鲜食玉米的高效低损收获,对鲜食玉米收获机械的发展进行阶段划分,并结合收获效率与果穗损失2个方面构建特征模式,基于模糊数学理论提出一种阶段划分方法,并结合4YZ-6型鲜食玉米收获机田间试验对该方法进行检验与可行性分析。结果表明该收获机收获效率与果穗损失率均低于2470型收获机,与判定的低效低损阶段相符。该阶段划即判定方法的提出,有助于加快我国鲜食玉米收获机械的高效低损发展,补全国内鲜食玉米机械化收获的短板问题。

丘陵山地小型窄幅分段式大豆收获机设计与试验

针对丘陵山地大豆收获小型宜机机具缺乏、损失率和破损率高等问题,设计一种丘陵山地小型窄幅分段式大豆收获机,该装置主要由拨禾轮、往复式割刀、输送链板等部件组成,主要围绕丘陵山地地貌特征、大豆植物生理学特性、收获及作业过程装备的动力学行为,优化拨禾轮的转速、安装高度、割刀往复速度、割刀和输送链板结构等参数。基于响应面单因素试验研究各因素对损失率、破损率影响的显著性大小顺序为:拨禾轮转速>割刀切割速度>拨禾轮高度。通过参数优化分析,确定大豆收获的最优作业参数组合为:拨禾轮转速51 r·min^(-1)、拨禾轮高度78 cm、割刀切割速度1.5 m·s^(-1),预测损失率为1.57%,破损率为1.4%。在最优工况下进行田间试验,结果表明收获机损失率由最高2.21%降为1.60%,破损率由最高2.03%降为1.35%,各指标实测值与模型优化值的相对误差均小于3%,满足国家相关标准要求。

大豆收获机割台关键技术及损失研究现状分析

割台作为大豆收获机的核心部件,其技术性能直接关系到大豆的收获质量和收获损失率。针对割台仿形设计、割台高度控制技术、影响割台损失率的关键技术展开研究和分析。首先,综述割台仿形机构与割台高度控制的结构、工作原理及关键技术,对比分析国内外的研究差距。其次,针对大豆炸荚、割台关键技术与割台损失的相关性进行深入分析,探讨割台损失产生的主要原因和影响因素,提出关键技术的改进建议。最后,展望我国大豆收获机割台在多元化、智能化与自动化方向的发展趋势,大豆炸荚生物特性及大豆收获机收获损失研究方面的发展趋势。研究发现,我国现有大豆收获机存在割台仿形性能差、割台自适应控制技术滞后、割台损失率偏高等问题。同时有效揭示国内大豆收机割台仿形机构、割台升降装置、割台的自适应性及割刀等关键技术存在的问题,割台振动、割台位置与仿形及撞击力导致割台损失率高的原因,为我国大豆收获机割台关键技术的突破创新及降低收获损失的进一步研究提供重要参考。

节粮减损背景下国内鲜食玉米低损收获现状及路径探究

减少鲜食玉米收获机收获作业时果穗的损失是推动鲜食玉米收获机械优化发展的重要研究方向。该文结合当前国内机收鲜食玉米低损收获现状,针对鲜食玉米收获机田间收获作业果穗损失较大的问题,阐述了鲜食玉米果穗的多种损失形式及产生原因,并结合多种果穗损失形式提出了一系列鲜食玉米低损机收的实现路径,为推动鲜食玉米收获机械的发展提供参考依据,有助于提高鲜食玉米产业经济效益。

基于电磁超材料的射频能量收集器设计及性能验证

设计了一种用于2.45GHz射频(RF)能量收集的超材料能量收集器,为典型的三明治结构,超材料谐振结构为互补开口谐振环(CSRR),介质层选用具有低损耗角正切特性的F4B材质。通过在CSRR的开口处打孔并加载负载电阻,实现了WiFi频段电磁(EM)能量的完美吸收。通过对收集器输入阻抗及多物理场分布的仿真,从不同方面分析了超材料能量收集器的吸波机理。样品的测试结果表明:所设计的超材料能量收集器能够在2.5 GHz达到89.3%的能量收集效率。验证了所设计的超材料谐振结构用于WiFi能量收集的可行性,可用于低功耗消费电子、医疗植入设备、物联网传感器节点等的主要或供电辅助来源。

自走式制种玉米联合收获机设计与试验

大田玉米收获机收获制种玉米时容易产生伤穗落籽、杂物堵塞等现象,本文针对适收期制种玉米生物特性,设计了一种大型制种玉米联合收获机,采用小行距对行柔性板式摘穗割台和可替换组合式剥皮装置,确保低损摘穗、输送、剥皮作业,降低籽粒损失与损伤;其中割台上方配备钢质覆胶弧形摘穗板,“橡胶+钢质”夹持输送链和六棱低速拉茎辊,可替换组合式剥皮装置采用柔性破皮+揉搓+降速组合形式。通过Plackett-Burman试验设计筛选提取影响机具指标的主要因素,采用Box-Behnken试验设计原理,以机具前进速度、拉茎辊转速和剥皮辊转速为试验因素,以总损失率与含杂率为性能指标,通过田间试验对机具进行检验,优化得出机具最佳作业参数。试验结果表明,优化后,当机具前进速度为4.87 km/h、拉茎辊转速为877.27 r/min、剥皮辊转速为442.52 r/min时,果穗总损失率为1.61%,含杂率为0.55%。田间试验结果表明,当收获机前进速度为4.9 km/h、拉茎辊转速为880 r/min、剥皮辊转速为450 r/min时,果穗总损失率为1.64%,含杂率为0.57%,满足制种玉米机械化联合收获的作业要求,可为制种玉米联合收获机设计与试验提供参考。

分布式光伏发电对电能采集及线损的影响分析

阐述分布式光伏发电对电能采集和线损的影响,包括电源接入对线损的影响、电源容量对线损的影响、电源位置对线损的影响、电源接入电压等级对线损的影响、窃电现象对台区线损的影响。

分布式光伏发电对电能采集及线损的影响分析

阐述分布式光伏发电对电能采集及线损的影响,包括电能存储和调节挑战、增加线路调节难度,从提升储能系统效率、优化电网调控机制方面,提出降低电能采集及线损影响的对策。

高粱机械化收获效果影响因素分析研究

针对高粱收获过程中的籽粒损失、破碎和含杂等问题,研究成熟时期和机收速率等因素对联合收获作业效果的影响规律。以晋杂22号高粱为研究对象,采用小区作业试验方案,分别在乳熟期、蜡熟期和完熟期设置3个机收速率水平进行高粱联合收获作业,机收速率设置为0.5 m/s,1.0 m/s,1.5 m/s,并测定破碎率、含杂率、总损失率与含水率等指标,获得成熟时期与机收速率对收获效果的影响规律。结果表明:成熟时期和机收速率对高粱籽粒含杂率、破碎率、总损失率等收获指标影响均极显著,对3项收获指标影响最大的因素均为成熟时期;在蜡熟期和机收速率为1.0 m/s时进行高粱联合收获作业能取得最佳效果,此时籽粒含水率为14.756%~15.746%,含杂率为0.14%,破碎率为0.29%,总损失率为5.48%。该研究获得了成熟时期和机收速率对高粱收获效果的影响规律,可为高粱机械化收获成熟时期合理选择与收获技术推广提供理论依据。